Screening of PHA-Producing Bacteria Using Biodiesel-Derived Waste Glycerol as a Sole Carbon Source (original) (raw)
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Biopolymer production by Bacterial Species using Glycerol, a byproduct of biodiesel
Biopolymer producing bacterial species (Bacillus and Pseudomonas )were isolated from rhizosphere soil of Jatropha curcas by using standard morphological, cultural and biochemical characteristics.PHB production by bacterial sps were screened by Sudan black B staining method. The main aim of the present study to production of biopolymers using crude glycerol is a byproduct of biodiesel, act as a sole carbon source for PHB producing microorganisms, under the limitation of nitrogen and phosphate . Ammonium molybdate and ammonium sulphate were used in nitrogen deficient medium instead of ammonium chloride. Maximum biopolymer production were noted in Bacillus spp13.3 gm/100ml.Pseudomonas spp yielded 11.2 gm/100 ml.
Engineering in Life Sciences, 2012
The ability of bacterial strains to assimilate glycerol derived from biodiesel facilities to produce metabolic compounds of importance for the food, textile and chemical industry, such as 1,3-propanediol (PD), 2,3-butanediol (BD) and ethanol (EtOH), was assessed. The screening of 84 bacterial strains was performed using glycerol as carbon source. After initial trials, 12 strains were identified capable of consuming raw glycerol under anaerobic conditions, whereas 5 strains consumed glycerol under aerobiosis. A plethora of metabolic compounds was synthesized; in anaerobic batch-bioreactor cultures PD in quantities up to 11.3 g/L was produced by Clostridium butyricum NRRL B-23495, while the respective value was 10.1 g/L for a newly isolated Citrobacter freundii. Adaptation of Cl. butyricum at higher initial glycerol concentration resulted in a PD max concentration of 32g/L.BDwasproducedbyanewEnterobacteraerogenesisolateinshake−flaskexperiments,underfullyaerobicconditions,withamaximumconcentrationof32 g/L. BD was produced by a new Enterobacter aerogenes isolate in shake-flask experiments, under fully aerobic conditions, with a maximum concentration of 32g/L.BDwasproducedbyanewEnterobacteraerogenesisolateinshake−flaskexperiments,underfullyaerobicconditions,withamaximumconcentrationof22 g/L which was achieved at an initial glycerol quantity of 55 g/L. A new Klebsiella oxytoca isolate converted waste glycerol into mixtures of PD, BD and EtOH at various ratios. Finally, another new C. freundii isolate converted waste glycerol into EtOH in anaerobic batch-bioreactor cultures with constant pH, achieving a final EtOH concentration of 14.5 g/L, a conversion yield of 0.45 g/g and a volumetric productivity of $0.7 g/L/h. As a conclusion, the current study confirmed the utilization of biodiesel-derived raw glycerol as an appropriate substrate for the production of PD, BD and EtOH by several newly isolated bacterial strains under different experimental conditions.
Annals of Microbiology, 2014
Increasing global concerns over plastic waste disposal and environmental awareness has already highlighted Polyhydroxyalkanoates (PHA's) as an increasingly attractive bioplastic option. In this regard, the present investigation aims to highlight the production of polyhydroxyalkanoate by Pseudomonas aeruginosa BPC2 (GeneBank entry: JQ866912) using a glycerol by-product as an inexpensive carbon source. The glycerol by-product was generated via the production of biodiesel from kitchen chimney dump lard (KCDL). The strain was also cultured in media comprising other carbon sources like glycerol (commercial), sugar cane molasses and glucose for comparative PHA yield. An appreciable PHA accumulation up to 22.5 % of cell dry weight was found when the bacterium was cultured in media comprised of glycerol by-product. The extracted bacterial biopolymer was further characterized by FTIR, GC-MS, GPC and TGA. The experimental results of the study warrant the feasibility of bacterial biopolymer production using glycerol byproduct as an inexpensive carbon source.
Isolated Microorganisms for Bioconversion of Biodiesel-Derived Glycerol Into 1,3-Propanediol
During biodiesel production, massive amounts of raw glycerol are created generating an environmental issue and the same time an increase of biodiesel production cost at the same time. This raw glycerol could be converted by specific strains into value-added products, like 1,3-propanediol (1,3-PD), an important monomer used in the synthesis of biodegradable polyesters. The present work is based on recent scientific articles and experimental studies on the targeted topic, namely on the use of bacterial strains for bioconversion of biodiesel-derived glycerol into valuable products, like 1,3-PD. Concentrations, yields and productivity of 1,3-PD are presented for various bacterial strains. Important results as respects the microbial bioconversion of biodiesel-derived glycerol into 1,3-PD were registered for strains like Klebsiella pneumoniae, Citrobacter freundii, Escherichia coli and Lactobacillus diolivorans. From this study can be concluded that waste glycerol may be used as a nutrient source for microbial development and the production of 1,3-propanediol with high concentrations and yields.
Trends in Sciences
Polyhydroxyalkanoates (PHAs) are a group of biopolymers used as an alternative to petroleum-based synthetic plastics. Their industrial application is not widely available due to production cost constraints, mainly from raw materials used for carbon sources. This research focuses on selecting a Bacillus strain from lipid-containing wastewater that can produce PHAs from crude glycerol and investigating the optimum conditions for producing PHAs from crude glycerol. The Bacillus strain was isolated from the wastewater storage pond at a fermented pork sausage manufacturing plant in Thailand for PHAs production utilizing Mineral Salt Medium (MSM) with 1 % w/v glucose as a carbon source. PHAs synthesis was preliminarily investigated by staining cells with Sudan Black B. The isolated FMI3 produced the highest PHAs at 43 % of the dry cell weight (DCW). It was identified as Bacillus pumilus FMI3. Crude glycerol was obtained from a by-product of the transesterification of waste cooking oil cat...
Biotechnology and Bioengineering, 2013
PHA, a naturally occurring biopolymer produced by a wide range of microorganisms, is known for its applications as bioplastic. In recent years the use of agroindustrial wastewater as substrate for PHA production by bacterial enrichments has attracted considerable research attention. Crude glycerol as generated during biodiesel production is a waste stream that due to its high organic matter content and low price could be an interesting substrate for PHA production. Previously we have demonstrated that when glycerol is used as substrate in a feast-famine regime, PHA and polyglucose are simultaneously produced as storage polymers. The work described in this paper aimed at understanding the effect of the cycle length on the bacterial enrichment process with emphasis on the distribution of glycerol towards PHA and polyglucose. Two sequencing batch reactors where operated with the same hydraulic and biomass retention time. A short cycle length (6 h) favored polyglucose production over PHA, whereas at long cycle length (24 h) PHA was more favored. In both communities the same microorganism appeared dominating, suggesting a metabolic rather than a microbial competition response. Moreover, the presence of ammonium during polymer accumulation did not influence the maximum amount of PHA that was attained.
Rapid screening method for isolation of glycerol-consuming bacteria for ethanol production
Sains Malaysiana, 2016
Large numbers of glycerol-consuming bacteria are present in nature; hence bioconversion of glycerol into biofuel which is bioethanol is one of the interests. The effective screening procedure is needed to screen and isolate broad ranges of bacteria from environment. The screening method was modified based on enzymatic oxidation of ethanol, which is correlated to reduction of 2,6-dichlorophenol-indophenol dye that resulted in the formation of yellow zone. Approximately 300 colonies were able to grow on minimal media using glycerol as sole carbon. Only about 70 isolates showed positive result when using the modified ethanol production assay after pre-screening stage. The formation of decolourized zone was apparent using modified assay containing 5 mL/L of 0.05M 2,6-dichlorophenol-indophenol, 10 mL of reaction mixture and 500 µl/L of enzyme, respectively. The ethanol production capability of the isolates was further proven by anaerobic fermentation as a quantitative method. This modified method is applicable in screening for ethanol producer from glycerol as carbon source allows rapid and more bacteria can be screened.
Biodiesel production by transesterification of vegetable oils and animal fats is continuously growing, as well the production of crude glycerol raising the problem on how to dispose it in an economic and eco-friendly way. On the parallel, the demand of green chemicals, such as polyhydroxyalkanoa-tes (PHAs) and biosurfactants (BSs), is raising being a valuable economic perspective for new industrial process-es. Some bacteria are able to synthesize PHAs and BSs by different carbon sources, therefore crude glycerol may be a suitable source for green chemicals high-value added compounds. In this work biodiesl glycerol from Brassica carinata oil was converted into PHAs and BS by. Pseudomo-nas mediterranea 9.1.After a preliminar evaluation of its capability to use the main components of crude glycerol the growth efficiency was optimized by addition of either meat or yeast extracts. Then, by apply-ing a mathematical mechanistic model, nutritional requirements were defined and the influence...
Biocatalysis and Agricultural Biotechnology, 2019
Burkholderia glumae MA13 was isolated from soil samples of Atlantic rain forest ecosystem as a new bacterial strain for polyhydroxyalkanoate (PHA) production from crude glycerol as sole carbon source. Among 107 glycerol consuming bacterial isolates, B. glumae MA13 was cultivated in shake flask experiments in order to verify its PHA production capability from crude glycerol besides waste cooking oil and sugarcane molasses free of pretreatment, showing intracellular poly(3-hydroxybutyrate) [P(3HB)] accumulation values of 51.3, 51.4 and 49% of cell dry weight (CDW), respectively. The addition of propionic or hexanoic acids to the media containing crude glycerol resulted in the copolymers poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] comprised of up to 32.1 mol% of 3HV monomer or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] with a maximum of 0.3 mol% of 3HHx, respectively. Fed-batch cultivation performed in a 10 L-scale bioreactor showed a maximum P(3HB-co-3HV) production of 9.9 g/L, which was 65.1% of total biomass and consisted of 21.8 mol% of 3HV monomer, with a maximum volumetric productivity of 0.22 g/(L h). The 3HV conversion yield achieved 1.04 g/g after 48 h cultivation, which was 76.7% of the maximum theoretical yield. B. glumae MA13 has showed to be an adapted bacterial strain to the synthesis of bioplastics from biofuel byproducts, and so from here it has been revealed as a promising PHA producer for an associated production set which has been considered as a prominent and ecologically friendly alternative to petrochemical plastics and fuels.
International Journal of Hydrogen Energy, 2016
One of the major challenges for the coming years is to develop alternative forms of producing sustainable energy. Biodiesel has shown to be an option in substituting fossil fuels. It is produced by transesterification of a fat and a monoalcohol, thus releasing glycerol, which corresponds to 10% of the reaction volume. Large increments in biodiesel production will result in proportional volumes of crude glycerol. Studies have shown that strict anaerobic bacteria and fermentative bacteria are able to produce biohydrogen, a highenergy fuel, which does not generate gaseous pollutants during its combustion. Given the importance of increasing the added value of crude glycerol, the purpose of this study was to isolate and characterize bacteria found in reactors of wastewater and activated sludge treatment able to produce biohydrogen from glycerol. Fifteen bacterial species able to grow in medium with glycerol were identified by sequencing of the 16S rRNA gene, of which nine species were found to be able to produce biohydrogen: Enterobacter ludwigii, Shigella sonnei, Bacillus licheniformis, Bacillus amyloliquefaciens, Staphylococcus warneri, Alcaligenes faecalis, Bacillus subtilis, Bacillus atrophaeus, and Citrobacter freundii. The isolates of Bacillus amyloliquefaciens showed higher yield in biohydrogen production with values of 0.50 ± 0.20 mol H 2 /mol of glycerol. The results indicate that there is a great potential for selecting biohydrogen-producing bacteria in the wastewater evaluated.