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Papers by Paola GONZALEZ

Journal of Basic Microbiology

Journal of hazardous materials, Jan 27, 2018

Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediat... more Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediate phenol and Cr(VI). To further understand the molecular mechanisms triggered in this strain during the bioremediation process, variations in the proteomic profile after treatment with phenol and phenol plus Cr(VI) were evaluated. The proteomic analysis revealed the induction of the β-ketoadipate pathway for phenol oxidation and the assimilation of degradation products through TCA cycle and glyoxylate shunt. Phenol exposure increased the abundance of proteins associated to energetic processes and ATP synthesis, but it also triggered cellular stress. The lipid bilayer was suggested as a target of phenol toxicity, and changing fatty acids composition seemed to be the bacterial response to protect the membrane integrity. The involvement of two flavoproteins in Cr(VI) reduction to Cr(III) was also proposed. The results suggested the important role of chaperones, antioxidant response and SOS-...

Environmental science and pollution research international, Jan 13, 2017

Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, i... more Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, is able to simultaneously remove high concentrations of Cr(VI) and phenol. In this complementary study, high-resolution microscopy techniques, such as atomic force microscopy (AFM) and transmission electron microscopy (TEM), were used to improve our understanding of some bacterial adaptive mechanisms that enhance their ability to survive. AFM contributed in gaining insight into changes in bacterial size and morphology. It allowed the unambiguous identification of pollutant-induced cellular disturbances and the visualization of bacterial cells with depth sensitivity. TEM analysis revealed that Cr(VI) produced changes mainly at the intracellular level, whereas phenol produced alterations at the membrane level. This strain tended to form more extensive biofilms after phenol treatment, which was consistent with microscopy images and the production of exopolysaccharides (EPSs). In addition, ot...

New biotechnology, Jan 16, 2017

Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore pollut... more Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore polluted sites. Traditionally, the search for microorganisms suitable for bioremediation has been based on the selection of isolated strains able to remove a specific type of pollutant. However, this strategy has now become obsolete, since co-pollution is a global reality. Thus, current studies attempt to find bacterial cultures capable of coping with a mixture of organic and inorganic compounds. In this sense, the bacterial consortium SFC 500-1 has demonstrated efficiency for Cr(VI) and phenol removal, both of which are found in many industrial wastewaters. In the present study, the ability of SFC 500-1 for simultaneous removal was improved through its entrapment in a Ca-alginate matrix. This strategy led to an increased removal of Cr(VI), which was partially reduced to Cr(III). Immobilised cells were able to tolerate and degrade phenol up to 1,500mg/l at high rates, forming catechol and cis,...

Environmental technology, Jan 27, 2016

The presence of chromium in soils not only affects the physiological processes of plants but also... more The presence of chromium in soils not only affects the physiological processes of plants but also the microbial rhizosphere composition and metabolic activities of microorganisms. Hence, the inoculation of plants with Cr(VI)-tolerant rhizospheric microorganisms as an alternative to reduce Cr phytotoxicity was studied. In this work, chickpea germination was reduced by Cr(VI) concentrations of 150 and 250 mg/L (6 and 33%, respectively); however lower Cr(VI) concentrations negatively affected the biomass. On the other hand, its symbiont, Mesorhizobium ciceri, was able to grow and remove different Cr(VI) concentrations (5-20 mg/L). The inoculation of chickpea plants with this strain exposed to Cr(VI) showed a significantly enhanced plant growth. In addition, inoculated plants accumulated higher Cr concentration in roots than those noninoculated. It is important to note that Cr was not translocated to shoots independently of inoculation. These results suggest that Mesorhizobium's cap...

Enzyme and Microbial Technology, 2006

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Here, we describe the removal of phenol from water using tomato hairy root cultures as source of enzymes, particularly peroxidases, which were capable to oxidise these compounds. Roots were able to remove phenol in the presence of H 2 O 2 5 mM, from solutions containing 100 mg/l of pollutant. Removal reached high values within 1 h and over a wide range of pH (4.0-9.0) and temperatures (20-60 • C). After phenol treatment, peroxidase activity of hairy root extracts decreased and isoenzyme patterns were affected. Neutral and basic peroxidases isoenzymes were slightly inactivated while the activities of acidic peroxidase isoenzymes remained without changes. Removal assays and kinetic studies performed using root extracts and purified peroxidases suggest that basic peroxidase isoenzymes would be the main peroxidases implicated in removal processes and they could be inactivated during the treatment. However, acidic peroxidase isoenzymes seemed to have little participation and retained their activities. These findings contribute to a better understanding of the enzymatic processes involved in phytoremediation of phenol and might have important implications in the use of these roots or their enzymes as inexpensive systems for decontamination of polluted environments.

Environmental Science and Pollution Research, Jan 11, 2012

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. Th... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Conventional treatments for phenol removal from industrial wastewaters have several limitations so, there is a need to look for alternative and environmental friendly technologies to complement or substitute the conventional ones. In recent years, phytoremediation has been recognized as a cheap and eco-friendly alternative technology which could be used for the remediation of organic contaminants, such as phenolics. Despite most phytoremediation studies were performed with soil-grown or hydroponically grown plants; more recently some results were obtained with the help of in vitro cell and tissue cultures, such as hairy roots. They have been used as tools for screening the potencialities of different plant species to tolerate, accumulate and remove high concentrations of phenols with high efficiency. In addition, using different plant model syst...

Environmental Science and Pollution Research, 2015

Bioremediation has emerged as an environmental friendly strategy to deal with environmental pollu... more Bioremediation has emerged as an environmental friendly strategy to deal with environmental pollution. Since the majority of polluted sites contain complex mixtures of inorganic and organic pollutants, it is important to find bacterial strains that can cope with multiple contaminants. In this work, a bacterial strain isolated from tannery sediments was identified as Acinetobacter guillouiae SFC 500-1A. This strain was able to simultaneously remove high phenol and Cr(VI) concentrations, and the mechanisms involved in such process were evaluated. The phenol biodegradation was catalized by a phenol-induced catechol 1,2-dioxygenase through an ortho-cleavage pathway. Also, NADH-dependent chromate reductase activity was measured in the cytosolic fraction. The ability of this strain to reduce Cr(VI) to Cr(III) was corroborated by detection of Cr(III) in cellular biomass after the removal process. While phenol did not affect significantly the chromate reductase activity, Cr(VI) was a major disruptor of catechol dioxygenase activity. Nevertheless, this activity was high even in presence of high Cr(VI) concentrations. Our results suggest the potential application of A. guillouiae SFC 500-1A for wastewaters treatment, and the obtained data provide the insights into the removal mechanisms, dynamics, and possible limitations of the bioremediation.

Recent Patents on Biotechnology, 2012

In the last years, hairy root (HR) cultures are gaining attention in the biotechnology industry. ... more In the last years, hairy root (HR) cultures are gaining attention in the biotechnology industry. This particular plant cell culture derives from explants infected with Agrobacterium rhizogenes. They constitute a relatively new approach to in vitro plant biotechnology and modern HR cultures are far away from the valuables findings performed by Philip R. White in the 1930's, who obtained indefinite growth of excised root tips. HR cultures are characterized by genetic and biochemical stability and high growth rate without expensive exogenous hormones source. HR cultures have allowed a deep study of plant metabolic pathways and the production of valuable secondary metabolites and enzymes, with therapeutic or industrial application. Furthermore, the potential of HR cultures is increasing continuously since different biotechnological strategies such as genetic engineering, elicitation and metabolic traps are currently being explored for discovery of new metabolites and pathways, as well as for increasing metabolites biosynthesis and/or secretion. Advances in design of proper bioreactors for HR growth are being of great interest, since scale up of metabolite production will allow the integration of this technology to industrial processes. Another application of HR cultures is related to their capabilities to biotransform and to degrade different xenobiotics. In this context, removal assays using this plant model system are useful tools for phytoremediation assays, previous to the application in the field. This review highlights the more recent application of HRs and those new patents which show their multiple utilities.

Environmental science and pollution research international, 2014

A native bacterial strain with high capability for Cr (VI) removal was isolated from tannery sedi... more A native bacterial strain with high capability for Cr (VI) removal was isolated from tannery sediments located in Elena (Córdoba Province, Argentina). The strain was characterized by amplification of 16S rRNA gene and identified as Serratia sp. C8. It was able to efficiently remove different Cr (VI) concentrations in a wide range of pHs and temperatures. The addition of different carbon sources as well as initial inoculum concentration were analyzed, demonstrating that Serratia sp. C8 could reduce 80 % of 20 mg/L Cr (VI) in a medium containing glucose 1 g/L, at pH 6-7 and 28 °C as optimal conditions, using 5 % inoculum concentration. The mechanisms involved in Cr (VI) removal were also evaluated. The strain was capable of biosorpting around 7.5-8.5 % of 20 mg/L Cr on its cell surface and to reduce Cr (VI). In addition, approximately a 54 and 46 % of total Cr was detected in the biomass and in the culture medium, respectively, and in the culture medium, Cr (III) was the predominant s...

Symbiosis, 2009

The effects of saline and osmotic stress on four peanut rhizobia, plant growth and symbiotic Nz-f... more The effects of saline and osmotic stress on four peanut rhizobia, plant growth and symbiotic Nz-fixation in Arachis hypogaea were studied. Abiotic stress was applied by adding either 100 mM NaCI or 20 mM PEG6000. At the rhizobial level, Bradyrhizobium ATCClO317 and TALlOOO showed stronger tolerance to stress than TALl371 and SEM1A6144. The effect of salinity on the bacterium-plant association was studied by using the variety Blanco Manfredi M68. In the absence of stresses, all the strains induced a significantly higher number of nodules on the roots, although TAL1371 and SEMIA6144 were more effective. Both stresses affected the interactionprocess, while TAL1371 was the best partner.

Plant Physiology and Biochemistry, 2013

Soybean (Glycine max) is often being cultivated in soils with moderate to high arsenic (As) conce... more Soybean (Glycine max) is often being cultivated in soils with moderate to high arsenic (As) concentrations or under irrigation with As contaminated groundwater. The purpose of this study was to determine the effect of As on soybean germination, development and nodulation in soybean-Bradyrhizobium japonicum E109 symbiosis, as a first-step approach to evaluate the impact of As on soybean production. Semi-hydroponic assays were conducted using soybean seedlings inoculated and non-inoculated with B. japonicum E109 and treated with arsenate or arsenite. Soybean germination and development, at early stage of growth, were significantly reduced from 10 μM arsenate or arsenite. This also was seen for soybean seedlings inoculated with B. japonicum mainly with arsenite where, in addition, the number of effective nodules was reduced, despite that the microorganism tolerated the metalloid. This minor nodulation could be due to a reduced motility (swarming and swimming) of the microorganism in presence of As. Arsenic concentration in roots was about 250-times higher than in shoots. Transference coefficient values indicated that As translocation to aerial parts was low and As accumulated mainly in roots, without significant differences between inoculated and non-inoculated plants. The presence of As restricted soybean-B. japonicum symbiosis and hence, the efficiency of most used commercial inoculants for soybean. Thus, water and/or soils containing As would negatively impact on soybean production, even in plants inoculated with B. japonicum E109.

Journal of Hazardous Materials, 2010

2,4-Dichlorophenol (2,4-DCP) is harmful for aquatic life and human health, so many attempts have ... more 2,4-Dichlorophenol (2,4-DCP) is harmful for aquatic life and human health, so many attempts have focused on removing it through innocuous technologies. Hairy roots (HR) represent an interesting plant system to study the process and to remove efficiently this compound. In the present work, tobacco HR clones were obtained and one of them was selected for 2,4-DCP phytoremediation assays. These cultures removed 2,4-DCP in short time and with high efficiency (98%, 88% and 83%) for solutions initially containing 250, 500 and 1000 mg/L, respectively. Removal process was mainly associated with peroxidase activity. The highest efficiency for 2,4-DCP (500 mg/L) removal was reached at 60 min and using 10 mM H 2 O 2. Moreover, HR could be re-used, almost for three consecutive cycles. The diminution of pH and the increase of chloride ions in post-removal solutions suggested that 2,4-DCP dehalogenation was mediated by peroxidases. Moreover, changes in deposition pattern of lignin in HR exposed to 2,4-DCP suggested that cell walls of xylem and phloem elements would be the site of deposition of some products formed and they would be a lignin-type polymer. These findings contribute to understand 2,4-DCP removal process with tobacco HR and it might have implications in the use of this system for decontamination of polluted waters.

Journal of Hazardous Materials, 2009

Phenol and their derivatives are used in several industries and they have a high potential toxici... more Phenol and their derivatives are used in several industries and they have a high potential toxicity for animal and plant species. They were found in variable concentrations, as high as 1000 mg/L, in industrial wastewater and, they are often discharged into the environment. Amphibian embryos are useful indicators of environmental pollution. However, to our knowledge, there are not studies focussed on the toxic effects of phenol on Bufo arenarum, which is an anuran widely distributed in South America. Therefore, the effect of phenol on the survival and morphogenesis of these amphibian embryos was evaluated by means of AMPHITOX test. Embryos at 25 stage of development (acute test) and embryos at 2-4 blastomers stage (early life stage test), were exposed to phenol solutions in concentrations ranging from 25 to 250 mg/L, which were frequently found in the environment. Mortality and malformations were registered each 24 h. LC 50 , LC 99 , NOEC, TC 50 and TI 50 values were 183.70, 250, 60, 113 mg/L and 1.62, respectively, at 96 h of treatment. Mortality and the percentage of malformations increased with increasing phenol concentrations. Teratogenic effects more frequently produced by phenol were: axial flexure, persistent yolk plug and different abnormalities which caused death of blastulaes. Moreover, other malformations were registered, such as irregular form, acephalism, edema, axial shortening and underdevelopment of gills, among others. Larvae of B. arenarum, at early embryonic stages (blastulae), showed higher sensitivity to phenol than tadpoles at stage 25. Results confirm high susceptibility of amphibians to phenol and that environmental concentrations of this pollutant might be harmful to these populations.

Journal of Basic Microbiology, 2000

We examined and compared the activities of synthetic and hydrolytic enzymes involved in trehalose... more We examined and compared the activities of synthetic and hydrolytic enzymes involved in trehalose metabolism, in three peanut rhizobia strains grown in control, hypersaline, and non-ionic hyperosmotic media. Results indicated that the effects of hyperosmolarity on the synthesis and the degradation of the disaccharide were diverse. In the salt-tolerant slow-growing strain Bradyrhizobium sp. ATCC 10317, we observed increased synthesis and accumulation of trehalose under hyperosmolarity imposed by either NaCl or PEG-8000. In the other two peanut rhizobia strains, the disaccharide level did not change under hypersalinity. In the salt-sensitive slow-growing strain Bradyrhizobium sp. USDA 3187, intracellular trehalose diminished in late stationary phase-cells grown with PEG, this reduction was accompanied by both an increased activity of synthetic enzymes and a decreased activity of trehalase. In the salt-tolerant fast-growing strain Rhizobium sp. TAL 1000, we also observed a reduction of intracellular trehalose under PEG-mediated growth, this decrease was early and transiently accompanied by an enhancement of trehalase activity, afterwards, the activity of synthetic enzymes augmented.

International Biodeterioration & Biodegradation, 2014

A bacterial strain resistant to phenol and Cr (VI) was isolated from an industrial polluted soil ... more A bacterial strain resistant to phenol and Cr (VI) was isolated from an industrial polluted soil of Córdoba province (Argentina), which was identified as Pantoea sp. FC 1. This microorganism was able to use phenol as sole carbon source. In addition it was capable of reducing Cr (VI) to Cr (III) in mineral and nutrient media. The isolated strain exhibited some properties as plant-growth promoting bacterium (PGPB), such as production of Indole Acetic Acid (IAA) and synthesis of siderophores, as well as being capable of solubilizing inorganic phosphates. A rhizoremediation system using the association Pantoea sp. FC 1-Brassica napus hairy roots (HRs) was tested for phenol and Cr (VI) removal in a hydroponic system. Microbial inoculation improved both phenol removal and chromium accumulation efficiency by HRs, showing a significant increase in Cr (III) accumulation compared to non-inoculated HRs, exceeding 1000 mg kg À1. Cr (III) was detected in HR biomass and supernatants, suggesting a possible Cr (VI) reducing activity of B. napus HRs. Basic studies in plant model systems, such as HRs, provide additional useful information that could facilitate the transition of this technology into plants suitable for practical rhizoremediation applications.

Enzyme and Microbial Technology, 2006

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Here, we describe the removal of phenol from water using tomato hairy root cultures as source of enzymes, particularly peroxidases, which were capable to oxidise these compounds. Roots were able to remove phenol in the presence of H 2 O 2 5 mM, from solutions containing 100 mg/l of pollutant. Removal reached high values within 1 h and over a wide range of pH (4.0-9.0) and temperatures (20-60 • C). After phenol treatment, peroxidase activity of hairy root extracts decreased and isoenzyme patterns were affected. Neutral and basic peroxidases isoenzymes were slightly inactivated while the activities of acidic peroxidase isoenzymes remained without changes. Removal assays and kinetic studies performed using root extracts and purified peroxidases suggest that basic peroxidase isoenzymes would be the main peroxidases implicated in removal processes and they could be inactivated during the treatment. However, acidic peroxidase isoenzymes seemed to have little participation and retained their activities. These findings contribute to a better understanding of the enzymatic processes involved in phytoremediation of phenol and might have important implications in the use of these roots or their enzymes as inexpensive systems for decontamination of polluted environments.

Journal of Basic Microbiology

Journal of hazardous materials, Jan 27, 2018

Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediat... more Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediate phenol and Cr(VI). To further understand the molecular mechanisms triggered in this strain during the bioremediation process, variations in the proteomic profile after treatment with phenol and phenol plus Cr(VI) were evaluated. The proteomic analysis revealed the induction of the β-ketoadipate pathway for phenol oxidation and the assimilation of degradation products through TCA cycle and glyoxylate shunt. Phenol exposure increased the abundance of proteins associated to energetic processes and ATP synthesis, but it also triggered cellular stress. The lipid bilayer was suggested as a target of phenol toxicity, and changing fatty acids composition seemed to be the bacterial response to protect the membrane integrity. The involvement of two flavoproteins in Cr(VI) reduction to Cr(III) was also proposed. The results suggested the important role of chaperones, antioxidant response and SOS-...

Environmental science and pollution research international, Jan 13, 2017

Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, i... more Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, is able to simultaneously remove high concentrations of Cr(VI) and phenol. In this complementary study, high-resolution microscopy techniques, such as atomic force microscopy (AFM) and transmission electron microscopy (TEM), were used to improve our understanding of some bacterial adaptive mechanisms that enhance their ability to survive. AFM contributed in gaining insight into changes in bacterial size and morphology. It allowed the unambiguous identification of pollutant-induced cellular disturbances and the visualization of bacterial cells with depth sensitivity. TEM analysis revealed that Cr(VI) produced changes mainly at the intracellular level, whereas phenol produced alterations at the membrane level. This strain tended to form more extensive biofilms after phenol treatment, which was consistent with microscopy images and the production of exopolysaccharides (EPSs). In addition, ot...

New biotechnology, Jan 16, 2017

Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore pollut... more Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore polluted sites. Traditionally, the search for microorganisms suitable for bioremediation has been based on the selection of isolated strains able to remove a specific type of pollutant. However, this strategy has now become obsolete, since co-pollution is a global reality. Thus, current studies attempt to find bacterial cultures capable of coping with a mixture of organic and inorganic compounds. In this sense, the bacterial consortium SFC 500-1 has demonstrated efficiency for Cr(VI) and phenol removal, both of which are found in many industrial wastewaters. In the present study, the ability of SFC 500-1 for simultaneous removal was improved through its entrapment in a Ca-alginate matrix. This strategy led to an increased removal of Cr(VI), which was partially reduced to Cr(III). Immobilised cells were able to tolerate and degrade phenol up to 1,500mg/l at high rates, forming catechol and cis,...

Environmental technology, Jan 27, 2016

The presence of chromium in soils not only affects the physiological processes of plants but also... more The presence of chromium in soils not only affects the physiological processes of plants but also the microbial rhizosphere composition and metabolic activities of microorganisms. Hence, the inoculation of plants with Cr(VI)-tolerant rhizospheric microorganisms as an alternative to reduce Cr phytotoxicity was studied. In this work, chickpea germination was reduced by Cr(VI) concentrations of 150 and 250 mg/L (6 and 33%, respectively); however lower Cr(VI) concentrations negatively affected the biomass. On the other hand, its symbiont, Mesorhizobium ciceri, was able to grow and remove different Cr(VI) concentrations (5-20 mg/L). The inoculation of chickpea plants with this strain exposed to Cr(VI) showed a significantly enhanced plant growth. In addition, inoculated plants accumulated higher Cr concentration in roots than those noninoculated. It is important to note that Cr was not translocated to shoots independently of inoculation. These results suggest that Mesorhizobium's cap...

Enzyme and Microbial Technology, 2006

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Here, we describe the removal of phenol from water using tomato hairy root cultures as source of enzymes, particularly peroxidases, which were capable to oxidise these compounds. Roots were able to remove phenol in the presence of H 2 O 2 5 mM, from solutions containing 100 mg/l of pollutant. Removal reached high values within 1 h and over a wide range of pH (4.0-9.0) and temperatures (20-60 • C). After phenol treatment, peroxidase activity of hairy root extracts decreased and isoenzyme patterns were affected. Neutral and basic peroxidases isoenzymes were slightly inactivated while the activities of acidic peroxidase isoenzymes remained without changes. Removal assays and kinetic studies performed using root extracts and purified peroxidases suggest that basic peroxidase isoenzymes would be the main peroxidases implicated in removal processes and they could be inactivated during the treatment. However, acidic peroxidase isoenzymes seemed to have little participation and retained their activities. These findings contribute to a better understanding of the enzymatic processes involved in phytoremediation of phenol and might have important implications in the use of these roots or their enzymes as inexpensive systems for decontamination of polluted environments.

Environmental Science and Pollution Research, Jan 11, 2012

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. Th... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Conventional treatments for phenol removal from industrial wastewaters have several limitations so, there is a need to look for alternative and environmental friendly technologies to complement or substitute the conventional ones. In recent years, phytoremediation has been recognized as a cheap and eco-friendly alternative technology which could be used for the remediation of organic contaminants, such as phenolics. Despite most phytoremediation studies were performed with soil-grown or hydroponically grown plants; more recently some results were obtained with the help of in vitro cell and tissue cultures, such as hairy roots. They have been used as tools for screening the potencialities of different plant species to tolerate, accumulate and remove high concentrations of phenols with high efficiency. In addition, using different plant model syst...

Environmental Science and Pollution Research, 2015

Bioremediation has emerged as an environmental friendly strategy to deal with environmental pollu... more Bioremediation has emerged as an environmental friendly strategy to deal with environmental pollution. Since the majority of polluted sites contain complex mixtures of inorganic and organic pollutants, it is important to find bacterial strains that can cope with multiple contaminants. In this work, a bacterial strain isolated from tannery sediments was identified as Acinetobacter guillouiae SFC 500-1A. This strain was able to simultaneously remove high phenol and Cr(VI) concentrations, and the mechanisms involved in such process were evaluated. The phenol biodegradation was catalized by a phenol-induced catechol 1,2-dioxygenase through an ortho-cleavage pathway. Also, NADH-dependent chromate reductase activity was measured in the cytosolic fraction. The ability of this strain to reduce Cr(VI) to Cr(III) was corroborated by detection of Cr(III) in cellular biomass after the removal process. While phenol did not affect significantly the chromate reductase activity, Cr(VI) was a major disruptor of catechol dioxygenase activity. Nevertheless, this activity was high even in presence of high Cr(VI) concentrations. Our results suggest the potential application of A. guillouiae SFC 500-1A for wastewaters treatment, and the obtained data provide the insights into the removal mechanisms, dynamics, and possible limitations of the bioremediation.

Recent Patents on Biotechnology, 2012

In the last years, hairy root (HR) cultures are gaining attention in the biotechnology industry. ... more In the last years, hairy root (HR) cultures are gaining attention in the biotechnology industry. This particular plant cell culture derives from explants infected with Agrobacterium rhizogenes. They constitute a relatively new approach to in vitro plant biotechnology and modern HR cultures are far away from the valuables findings performed by Philip R. White in the 1930's, who obtained indefinite growth of excised root tips. HR cultures are characterized by genetic and biochemical stability and high growth rate without expensive exogenous hormones source. HR cultures have allowed a deep study of plant metabolic pathways and the production of valuable secondary metabolites and enzymes, with therapeutic or industrial application. Furthermore, the potential of HR cultures is increasing continuously since different biotechnological strategies such as genetic engineering, elicitation and metabolic traps are currently being explored for discovery of new metabolites and pathways, as well as for increasing metabolites biosynthesis and/or secretion. Advances in design of proper bioreactors for HR growth are being of great interest, since scale up of metabolite production will allow the integration of this technology to industrial processes. Another application of HR cultures is related to their capabilities to biotransform and to degrade different xenobiotics. In this context, removal assays using this plant model system are useful tools for phytoremediation assays, previous to the application in the field. This review highlights the more recent application of HRs and those new patents which show their multiple utilities.

Environmental science and pollution research international, 2014

A native bacterial strain with high capability for Cr (VI) removal was isolated from tannery sedi... more A native bacterial strain with high capability for Cr (VI) removal was isolated from tannery sediments located in Elena (Córdoba Province, Argentina). The strain was characterized by amplification of 16S rRNA gene and identified as Serratia sp. C8. It was able to efficiently remove different Cr (VI) concentrations in a wide range of pHs and temperatures. The addition of different carbon sources as well as initial inoculum concentration were analyzed, demonstrating that Serratia sp. C8 could reduce 80 % of 20 mg/L Cr (VI) in a medium containing glucose 1 g/L, at pH 6-7 and 28 °C as optimal conditions, using 5 % inoculum concentration. The mechanisms involved in Cr (VI) removal were also evaluated. The strain was capable of biosorpting around 7.5-8.5 % of 20 mg/L Cr on its cell surface and to reduce Cr (VI). In addition, approximately a 54 and 46 % of total Cr was detected in the biomass and in the culture medium, respectively, and in the culture medium, Cr (III) was the predominant s...

Symbiosis, 2009

The effects of saline and osmotic stress on four peanut rhizobia, plant growth and symbiotic Nz-f... more The effects of saline and osmotic stress on four peanut rhizobia, plant growth and symbiotic Nz-fixation in Arachis hypogaea were studied. Abiotic stress was applied by adding either 100 mM NaCI or 20 mM PEG6000. At the rhizobial level, Bradyrhizobium ATCClO317 and TALlOOO showed stronger tolerance to stress than TALl371 and SEM1A6144. The effect of salinity on the bacterium-plant association was studied by using the variety Blanco Manfredi M68. In the absence of stresses, all the strains induced a significantly higher number of nodules on the roots, although TAL1371 and SEMIA6144 were more effective. Both stresses affected the interactionprocess, while TAL1371 was the best partner.

Plant Physiology and Biochemistry, 2013

Soybean (Glycine max) is often being cultivated in soils with moderate to high arsenic (As) conce... more Soybean (Glycine max) is often being cultivated in soils with moderate to high arsenic (As) concentrations or under irrigation with As contaminated groundwater. The purpose of this study was to determine the effect of As on soybean germination, development and nodulation in soybean-Bradyrhizobium japonicum E109 symbiosis, as a first-step approach to evaluate the impact of As on soybean production. Semi-hydroponic assays were conducted using soybean seedlings inoculated and non-inoculated with B. japonicum E109 and treated with arsenate or arsenite. Soybean germination and development, at early stage of growth, were significantly reduced from 10 μM arsenate or arsenite. This also was seen for soybean seedlings inoculated with B. japonicum mainly with arsenite where, in addition, the number of effective nodules was reduced, despite that the microorganism tolerated the metalloid. This minor nodulation could be due to a reduced motility (swarming and swimming) of the microorganism in presence of As. Arsenic concentration in roots was about 250-times higher than in shoots. Transference coefficient values indicated that As translocation to aerial parts was low and As accumulated mainly in roots, without significant differences between inoculated and non-inoculated plants. The presence of As restricted soybean-B. japonicum symbiosis and hence, the efficiency of most used commercial inoculants for soybean. Thus, water and/or soils containing As would negatively impact on soybean production, even in plants inoculated with B. japonicum E109.

Journal of Hazardous Materials, 2010

2,4-Dichlorophenol (2,4-DCP) is harmful for aquatic life and human health, so many attempts have ... more 2,4-Dichlorophenol (2,4-DCP) is harmful for aquatic life and human health, so many attempts have focused on removing it through innocuous technologies. Hairy roots (HR) represent an interesting plant system to study the process and to remove efficiently this compound. In the present work, tobacco HR clones were obtained and one of them was selected for 2,4-DCP phytoremediation assays. These cultures removed 2,4-DCP in short time and with high efficiency (98%, 88% and 83%) for solutions initially containing 250, 500 and 1000 mg/L, respectively. Removal process was mainly associated with peroxidase activity. The highest efficiency for 2,4-DCP (500 mg/L) removal was reached at 60 min and using 10 mM H 2 O 2. Moreover, HR could be re-used, almost for three consecutive cycles. The diminution of pH and the increase of chloride ions in post-removal solutions suggested that 2,4-DCP dehalogenation was mediated by peroxidases. Moreover, changes in deposition pattern of lignin in HR exposed to 2,4-DCP suggested that cell walls of xylem and phloem elements would be the site of deposition of some products formed and they would be a lignin-type polymer. These findings contribute to understand 2,4-DCP removal process with tobacco HR and it might have implications in the use of this system for decontamination of polluted waters.

Journal of Hazardous Materials, 2009

Phenol and their derivatives are used in several industries and they have a high potential toxici... more Phenol and their derivatives are used in several industries and they have a high potential toxicity for animal and plant species. They were found in variable concentrations, as high as 1000 mg/L, in industrial wastewater and, they are often discharged into the environment. Amphibian embryos are useful indicators of environmental pollution. However, to our knowledge, there are not studies focussed on the toxic effects of phenol on Bufo arenarum, which is an anuran widely distributed in South America. Therefore, the effect of phenol on the survival and morphogenesis of these amphibian embryos was evaluated by means of AMPHITOX test. Embryos at 25 stage of development (acute test) and embryos at 2-4 blastomers stage (early life stage test), were exposed to phenol solutions in concentrations ranging from 25 to 250 mg/L, which were frequently found in the environment. Mortality and malformations were registered each 24 h. LC 50 , LC 99 , NOEC, TC 50 and TI 50 values were 183.70, 250, 60, 113 mg/L and 1.62, respectively, at 96 h of treatment. Mortality and the percentage of malformations increased with increasing phenol concentrations. Teratogenic effects more frequently produced by phenol were: axial flexure, persistent yolk plug and different abnormalities which caused death of blastulaes. Moreover, other malformations were registered, such as irregular form, acephalism, edema, axial shortening and underdevelopment of gills, among others. Larvae of B. arenarum, at early embryonic stages (blastulae), showed higher sensitivity to phenol than tadpoles at stage 25. Results confirm high susceptibility of amphibians to phenol and that environmental concentrations of this pollutant might be harmful to these populations.

Journal of Basic Microbiology, 2000

We examined and compared the activities of synthetic and hydrolytic enzymes involved in trehalose... more We examined and compared the activities of synthetic and hydrolytic enzymes involved in trehalose metabolism, in three peanut rhizobia strains grown in control, hypersaline, and non-ionic hyperosmotic media. Results indicated that the effects of hyperosmolarity on the synthesis and the degradation of the disaccharide were diverse. In the salt-tolerant slow-growing strain Bradyrhizobium sp. ATCC 10317, we observed increased synthesis and accumulation of trehalose under hyperosmolarity imposed by either NaCl or PEG-8000. In the other two peanut rhizobia strains, the disaccharide level did not change under hypersalinity. In the salt-sensitive slow-growing strain Bradyrhizobium sp. USDA 3187, intracellular trehalose diminished in late stationary phase-cells grown with PEG, this reduction was accompanied by both an increased activity of synthetic enzymes and a decreased activity of trehalase. In the salt-tolerant fast-growing strain Rhizobium sp. TAL 1000, we also observed a reduction of intracellular trehalose under PEG-mediated growth, this decrease was early and transiently accompanied by an enhancement of trehalase activity, afterwards, the activity of synthetic enzymes augmented.

International Biodeterioration & Biodegradation, 2014

A bacterial strain resistant to phenol and Cr (VI) was isolated from an industrial polluted soil ... more A bacterial strain resistant to phenol and Cr (VI) was isolated from an industrial polluted soil of Córdoba province (Argentina), which was identified as Pantoea sp. FC 1. This microorganism was able to use phenol as sole carbon source. In addition it was capable of reducing Cr (VI) to Cr (III) in mineral and nutrient media. The isolated strain exhibited some properties as plant-growth promoting bacterium (PGPB), such as production of Indole Acetic Acid (IAA) and synthesis of siderophores, as well as being capable of solubilizing inorganic phosphates. A rhizoremediation system using the association Pantoea sp. FC 1-Brassica napus hairy roots (HRs) was tested for phenol and Cr (VI) removal in a hydroponic system. Microbial inoculation improved both phenol removal and chromium accumulation efficiency by HRs, showing a significant increase in Cr (III) accumulation compared to non-inoculated HRs, exceeding 1000 mg kg À1. Cr (III) was detected in HR biomass and supernatants, suggesting a possible Cr (VI) reducing activity of B. napus HRs. Basic studies in plant model systems, such as HRs, provide additional useful information that could facilitate the transition of this technology into plants suitable for practical rhizoremediation applications.

Enzyme and Microbial Technology, 2006

Phenolic compounds present in the drainage from several industries are harmful pollutants and rep... more Phenolic compounds present in the drainage from several industries are harmful pollutants and represent a potential danger to human health. Here, we describe the removal of phenol from water using tomato hairy root cultures as source of enzymes, particularly peroxidases, which were capable to oxidise these compounds. Roots were able to remove phenol in the presence of H 2 O 2 5 mM, from solutions containing 100 mg/l of pollutant. Removal reached high values within 1 h and over a wide range of pH (4.0-9.0) and temperatures (20-60 • C). After phenol treatment, peroxidase activity of hairy root extracts decreased and isoenzyme patterns were affected. Neutral and basic peroxidases isoenzymes were slightly inactivated while the activities of acidic peroxidase isoenzymes remained without changes. Removal assays and kinetic studies performed using root extracts and purified peroxidases suggest that basic peroxidase isoenzymes would be the main peroxidases implicated in removal processes and they could be inactivated during the treatment. However, acidic peroxidase isoenzymes seemed to have little participation and retained their activities. These findings contribute to a better understanding of the enzymatic processes involved in phytoremediation of phenol and might have important implications in the use of these roots or their enzymes as inexpensive systems for decontamination of polluted environments.