Trevor Stevenson - Academia.edu (original) (raw)

Papers by Trevor Stevenson

Research paper thumbnail of Bacterial Form II Rubisco can support wild-type growth and productivity in Solanum tuberosum cv. Desiree (potato) under elevated CO2

PNAS Nexus

The last decade has seen significant advances in the development of approaches for improving both... more The last decade has seen significant advances in the development of approaches for improving both the light harvesting and carbon fixation pathways of photosynthesis by nuclear transformation, many involving multigene synthetic biology approaches. As efforts to replicate these accomplishments from tobacco into crops gather momentum, similar diversification is needed in the range of transgenic options available, including capabilities to modify crop photosynthesis by chloroplast transformation. To address this need, here we describe the first transplastomic modification of photosynthesis in a crop by replacing the native Rubisco in potato with the faster, but lower CO2-affinity and poorer CO2/O2 specificity Rubisco from the bacterium Rhodospirillum rubrum. High level production of R. rubrum Rubisco in the potRr genotype (8 to 10 µmol catalytic sites m2) allowed it to attain wild-type levels of productivity, including tuber yield, in air containing 0.5% (v/v) CO2. Under controlled env...

Research paper thumbnail of Expression of Brassica oleracea FtsZ1-1 and MinD alters chloroplast division in Nicotiana tabacum generating macro- and mini-chloroplasts

Plant Cell Reports, 2011

FtsZ1-1 and MinD plastid division-related genes were identified and cloned from Brassica oleracea... more FtsZ1-1 and MinD plastid division-related genes were identified and cloned from Brassica oleracea var. botrytis. Transgenic tobacco plants expressing BoFtsZ1-1 or BoMinD exhibited cells with either fewer but abnormally large chloroplasts or more but smaller chloroplasts relative to wild-type tobacco plants. An abnormal chloroplast phenotype in guard cells was found in BoMinD transgenic tobacco plants but not in BoFtsZ1-1 transgenic tobacco plants. Transgenic tobacco plants bearing the macro-chloroplast phenotype had 10 to 20-fold increased levels of total FtsZ1-1 or MinD, whilst the transgenic tobacco plants bearing the mini-chloroplast phenotype had lower increased FtsZ1-1 or absence of detectable MinD. We also described for the first time, plastid transformation of macro-chloroplast bearing tobacco shoots with a gene cassette allowing for expression of green fluorescent protein (GFP). Homoplasmic plastid transformants from normal chloroplast and macro-chloroplast tobacco plants expressing GFP were obtained. Both types of transformants accumulated GFP at ~6% of total soluble protein, thus indicating that cells containing macro-chloroplasts can regenerate shoots in tissue culture and can stably integrate and express a foreign gene to similar levels as plant cells containing a normal chloroplast size and number.

Research paper thumbnail of Co-expression of microbial cellulases in transgenic wheat as a potential source for cellulosic ethanol production

Plant Biotechnology, 2015

Research paper thumbnail of LC-MS untargeted metabolomics assesses the delayed response of glufosinate treatment of transgenic glufosinate resistant (GR) buffalo grasses (Stenotaphrum secundatum L.)

Metabolomics : Official journal of the Metabolomic Society, 2021

INTRODUCTION Glufosinate resistant (GR) buffalo grasses were genetically modified to resist the b... more INTRODUCTION Glufosinate resistant (GR) buffalo grasses were genetically modified to resist the broad-spectrum herbicide, glufosinate by inserting a novel pat gene into its genome. This modification results in a production of additional phosphinothricin acetyltransferase (PAT) to detoxify the deleterious effects of glufosinate. The GR grasses and its associated herbicide form a modern, weeding program, to eradicate obnoxious weeds in turf lawn without damaging the grasses at relatively low costs and labor. As with several principal crops which are genetically modified to improve agricultural traits, biosafety of the GR buffalo grasses is inevitably expected to become a public concern. For the first time, we had previously examined the metabolome of glufosinate-resistant buffalo grasses, using a GC-MS untargeted approach to assess the risk of GR as well as identify any pleotropic effects arising from the genetically modification process. In this paper, an untargeted high-resolution L...

Research paper thumbnail of Algae: an essential link between our past and future

Microbiology Australia

Interest in the replacement of imported fossil-based fuels with home-grown, renewable and cheap s... more Interest in the replacement of imported fossil-based fuels with home-grown, renewable and cheap sources of energy spikes each time we are paying over $1.50/litre for petrol. This time, however, the danger of an energy shortage coincides with an increasing level of atmospheric CO2 and an approaching global food shortage. This all dictates an urgency for the development of a new generation of feedstocks that will not only produce biofuels or their various components, but that can also be used for feeding animals and humans and at the same time will reduce a level of atmospheric CO2. These feedstock organisms have to be grown on marginal lands not used for food crops and require low inputs of fresh water and fertiliser. Further adding to this wish list is that these feedstocks could also grow in sea water, can utilise animal and human waste and be used as fertilisers for crops. All of this will finish a portrait of algae, a group of aquatic, photosynthetic, organisms ranging in size fr...

Research paper thumbnail of Utilization of GC–MS untargeted metabolomics to assess the delayed response of glufosinate treatment of transgenic herbicide resistant (HR) buffalo grasses (Stenotaphrum secundatum L.)

Research paper thumbnail of Mutations in humans and animals which affect copper metabolism

Journal of Inherited Metabolic Disease, Feb 1, 1983

Research paper thumbnail of Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells

Biotechnology for biofuels, 2015

Numerous strategies have evolved recently for the generation of genetically modified or synthetic... more Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive. This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its geneticall...

Research paper thumbnail of Molecular Biology of Flavonoid Pigment Biosynthesis in Flowers

Plant Gene Research, 1991

Go to AGRIS search. Molecular biology of flavonoid pigment biosynthesis in flowers. Stevenson, TW... more Go to AGRIS search. Molecular biology of flavonoid pigment biosynthesis in flowers. Stevenson, TW (Calgene Pacific Pty Ltd., Victoria, Australia). ... Source, Molecular approaches to crop improvement, Dennis, ESLlewellyn, DJ (eds.), [nd].- ISBN 03-878-22305. p. 127-148. ...

Research paper thumbnail of Gene Flow and Risk Assessment in Genetically Modified Crops

Alien Gene Transfer in Crop Plants, Volume 1, 2013

Research paper thumbnail of Production and characterisation of transgenic cauliflower plants containing abnormal chloroplasts

Scientia Horticulturae, 2013

Research paper thumbnail of Isolation and characterisation of a cDNA clone encoding cinnamyl alcohol dehydrogenase in Eucalyptus globulus Labill

Plant Science, 1999

Cinnamyl alcohol dehydrogenase (CAD) (EC 1.1.1.195) catalyses the final step in lignin precursor ... more Cinnamyl alcohol dehydrogenase (CAD) (EC 1.1.1.195) catalyses the final step in lignin precursor synthesis reducing the cinnamyl aldehydes (para-coumaryl, coniferyl and sinapyl aldehydes) to the corresponding alcohols in the presence of NADPH. In this paper, we report the molecular cloning and characterisation of a Eucalyptus globulus genomic fragment encoding CAD2, and the corresponding full-length cDNA isolated from young stem material. This was achieved using the polymerase chain reaction-based method known as rapid amplification of cDNA ends, with oligonucleotide primers corresponding to regions of homology between CAD-encoding sequences from other eucalypt species. The identity of the clones was inferred by sequence data comparison and the cDNA sequence (1423 bp) was found to encode a protein of 356 amino acid residues. The CAD2 transcript was most abundant in stem, followed by root and midrib tissues, which corresponds with the role of lignin in water retention in plants and in providing mechanical support. Low level expression was also observed in leaf tissue. Southern blot analysis revealed a single CAD gene in this species with the presence of possibly different allelic representations.

Research paper thumbnail of Mutations in humans and animals which affect copper metabolism

Journal of Inherited Metabolic Disease, 1983

Research paper thumbnail of Dual application of duckweed and azolla plants for wastewater treatment and renewable fuels and petrochemicals production

Biotechnology for Biofuels, 2014

Background: Shortages in fresh water supplies today affects more than 1 billion people worldwide.... more Background: Shortages in fresh water supplies today affects more than 1 billion people worldwide. Phytoremediation strategies, based on the abilities of aquatic plants to recycle nutrients offer an attractive solution for the bioremediation of water pollution and represents one of the most globally researched issues. The subsequent application of the biomass from the remediation for the production of fuels and petrochemicals offers an ecologically friendly and cost-effective solution for water pollution problems and production of value-added products. Results: In this paper, the feasibility of the dual application of duckweed and azolla aquatic plants for wastewater treatment and production of renewable fuels and petrochemicals is explored. The differences in absorption rates of the key wastewater nutrients, ammonium and phosphorus by these aquatic macrophytes were used as the basis for optimization of the composition of wastewater effluents. Analysis of pyrolysis products showed that azolla and algae produce a similar range of bio-oils that contain a large spectrum of petrochemicals including straight-chain C10-C21 alkanes, which can be directly used as diesel fuel supplement, or a glycerin-free component of biodiesel. Pyrolysis of duckweed produces a different range of bio-oil components that can potentially be used for the production of "green" gasoline and diesel fuel using existing techniques, such as catalytic hydrodeoxygenation. Conclusions: Differences in absorption rates of the key wastewater nutrients, ammonium and phosphorus by different aquatic macrophytes can be used for optimization of composition of wastewater effluents. The generated data suggest that the composition of the petrochemicals can be modified in a targeted fashion, not only by using different species, but also by changing the source plants' metabolic profile, by exposing them to different abiotic or biotic stresses. This study presents an attractive, ecologically friendly and cost-effective solution for efficient bio-filtration of swine wastewater and petrochemicals production from generated biomass.

Research paper thumbnail of Copper induction of translatable metallothionein messenger RNA

Bioscience Reports, 1981

Copper chloride injection of rats resulted in a 4.5- to 9-fold increase in translatable metalloth... more Copper chloride injection of rats resulted in a 4.5- to 9-fold increase in translatable metallothionein messenger RNA in the liver. Metallothionein in the translation products was identified on the basis of high cysteine and serine incorporation and absence of leucine incorporation as well as comigration with authentic zinc-induced rat-liver metallothionein on SDS-polyacrylamide gels.

Research paper thumbnail of Co-expression of microbial cellulases in transgenic wheat as a potential source for cellulosic ethanol production

Crop residues are produced in abundance in agriculture and forestry and are a potential source of... more Crop residues are produced in abundance in agriculture and forestry and are a potential source of lignocellulosic biomass for ethanol production. Recent research has included the heterologous expression in transgenic plants of genes encoding cellulases to produce fermentable sugars from plant biomass. In this study, transgenic wheat lines were generated co-expressing the genes for an endoglucanase 1 (E1) of Acidothermus cellulolyticus and cellobiohydrolase 1 (CBH1) of Trichoderma reesei. Both genes were under the control of a wheat Rubisco small subunit promoter (RbcS). Transgenic wheat leaves accumulated apoplast targeted E1 and CBH1 proteins at levels up to 1 and 0.5% respectively of total soluble protein as determined by immunoblotting. Transgenic plants co-expressing E1 and CBH1 were analysed by a 4-methylumbelliferyl-β-D-cellobioside (MUC) assay and enzymatic activity was detected up to 92 nmol 4-MU/mg tsp/min.

Research paper thumbnail of Characterization of Flavonoid 3',5'Hydroxylase in Microsomal Membrane Fraction of Petunia hybrida Flowers

We have detected a flavonoid 3',5'-hydroxylase (F3',5'H) in the microsomal fracti... more We have detected a flavonoid 3',5'-hydroxylase (F3',5'H) in the microsomal fraction of Petunia hybrida flowers. Activity varied with the development of flowers, peaking immediately prior to and during anthesis, but was absent in mature flowers. F3',5'H activity in flower extracts from genetically defined floral color mutants correlated strictly with the genotypes Hfl and Hf2. No activity was detected in flowers

Research paper thumbnail of Developmental variation in copper, zinc and metallothionein mRNA in brindled mutant and nutritionally copper deficient mice

Biochimica Et Biophysica Acta-molecular Basis of Disease, 1991

The concentrations of copper, zinc and metallothionein-I (MT-I) mRNA were determined in the liver... more The concentrations of copper, zinc and metallothionein-I (MT-I) mRNA were determined in the liver, kidney and brain of the brindled mutant mouse from birth until the time of death. Despite accumulation of copper in the kidney of the mutant, MT-I mRNA concentrations were normal. There was no difference between the MT-I mRNA in the brain of mutant and normal in the first 10 days of life, but after day 10 metallothionein mRNA levels were increased in the mutant. The concentration of copper was very low in the liver of the mutant, and on day 6 after birth the metallothionein mRNA was also reduced by about 50%. This reduction was not seen in copper-deficient 6-day-old pups, despite very low hepatic copper levels. This suggests that the lower hepatic MT-I mRNA in the day 6 brindled mouse was not simply due to the reduction in hepatic copper and also that hepatic copper is not regulating metallothionein gene expression the liver of neonatal mice. After day 12 hepatic MT-I mRNA levels were elevated in mutant and in copper deficient mice, both of which die at 14 to 16 days. These increases and the increase in brain MT-I mRNA in older mutant mice are likely to be caused by stress. Overall the results support the conclusions that the brindled mutation does not cause a constitutive activation of the metallothionein genes, and that the differences in metallothionein mRNA between mutant and normal are most probably secondary consequences of the mutation.

Research paper thumbnail of Fungal-assisted algal flocculation: application in wastewater treatment and biofuel production

Biotechnology for Biofuels, 2015

Background: The microalgal-based industries are facing a number of important challenges that in t... more Background: The microalgal-based industries are facing a number of important challenges that in turn affect their economic viability. Arguably the most important of these are associated with the high costs of harvesting and dewatering of the microalgal cells, the costs and sustainability of nutrient supplies and costly methods for large scale oil extraction. Existing harvesting technologies, which can account for up to 50% of the total cost, are not economically feasible because of either requiring too much energy or the addition of chemicals. Fungal-assisted flocculation is currently receiving increased attention because of its high harvesting efficiency. Moreover, some of fungal and microalgal strains are well known for their ability to treat wastewater, generating biomass which represents a renewable and sustainable feedstock for bioenergy production.

Research paper thumbnail of Application of Aquatic Plants for the Treatment of Selenium-Rich Mining Wastewater and Production of Renewable Fuels and Petrochemicals

Journal of Sustainable Bioenergy Systems, 2014

Aquatic plants aggressively colonising wetlands are widely used for the biosorption of the solubl... more Aquatic plants aggressively colonising wetlands are widely used for the biosorption of the soluble contaminants from wastewater and represent an attractive feedstock for biofuel production. Three common Australian aquatic plants, duckweed (Landoltia punctata), elodea, (Elodea canadensis) and water clover (Marsilea quadrifolia), colonizing different depths of wetlands were tested for their ability to treat the selenium-rich mining wastewater and for their potential for production of petrochemicals. The results showed that these plants could be effective at biofiltration of selenium and heavy metals from mining wastewater accumulating them in their fast growing biomass. Along with production of bio-gas and bio-solid components, pyrolysis of these plants produced a range of liquid petrochemicals including straight-chain C14-C20 alkanes, which can be directly used as a diesel fuel supplement or as a glycerine-free component of biodiesel. Other identified bio-oil components can be converted into petrochemicals using existing techniques such as catalytic hydrodeoxygenation. A dual application of aquatic plants for wastewater treatment and production of value-added chemicals offers an ecologically friendly and cost-effective solution for water pollution problems and renewable energy production.

Research paper thumbnail of Bacterial Form II Rubisco can support wild-type growth and productivity in Solanum tuberosum cv. Desiree (potato) under elevated CO2

PNAS Nexus

The last decade has seen significant advances in the development of approaches for improving both... more The last decade has seen significant advances in the development of approaches for improving both the light harvesting and carbon fixation pathways of photosynthesis by nuclear transformation, many involving multigene synthetic biology approaches. As efforts to replicate these accomplishments from tobacco into crops gather momentum, similar diversification is needed in the range of transgenic options available, including capabilities to modify crop photosynthesis by chloroplast transformation. To address this need, here we describe the first transplastomic modification of photosynthesis in a crop by replacing the native Rubisco in potato with the faster, but lower CO2-affinity and poorer CO2/O2 specificity Rubisco from the bacterium Rhodospirillum rubrum. High level production of R. rubrum Rubisco in the potRr genotype (8 to 10 µmol catalytic sites m2) allowed it to attain wild-type levels of productivity, including tuber yield, in air containing 0.5% (v/v) CO2. Under controlled env...

Research paper thumbnail of Expression of Brassica oleracea FtsZ1-1 and MinD alters chloroplast division in Nicotiana tabacum generating macro- and mini-chloroplasts

Plant Cell Reports, 2011

FtsZ1-1 and MinD plastid division-related genes were identified and cloned from Brassica oleracea... more FtsZ1-1 and MinD plastid division-related genes were identified and cloned from Brassica oleracea var. botrytis. Transgenic tobacco plants expressing BoFtsZ1-1 or BoMinD exhibited cells with either fewer but abnormally large chloroplasts or more but smaller chloroplasts relative to wild-type tobacco plants. An abnormal chloroplast phenotype in guard cells was found in BoMinD transgenic tobacco plants but not in BoFtsZ1-1 transgenic tobacco plants. Transgenic tobacco plants bearing the macro-chloroplast phenotype had 10 to 20-fold increased levels of total FtsZ1-1 or MinD, whilst the transgenic tobacco plants bearing the mini-chloroplast phenotype had lower increased FtsZ1-1 or absence of detectable MinD. We also described for the first time, plastid transformation of macro-chloroplast bearing tobacco shoots with a gene cassette allowing for expression of green fluorescent protein (GFP). Homoplasmic plastid transformants from normal chloroplast and macro-chloroplast tobacco plants expressing GFP were obtained. Both types of transformants accumulated GFP at ~6% of total soluble protein, thus indicating that cells containing macro-chloroplasts can regenerate shoots in tissue culture and can stably integrate and express a foreign gene to similar levels as plant cells containing a normal chloroplast size and number.

Research paper thumbnail of Co-expression of microbial cellulases in transgenic wheat as a potential source for cellulosic ethanol production

Plant Biotechnology, 2015

Research paper thumbnail of LC-MS untargeted metabolomics assesses the delayed response of glufosinate treatment of transgenic glufosinate resistant (GR) buffalo grasses (Stenotaphrum secundatum L.)

Metabolomics : Official journal of the Metabolomic Society, 2021

INTRODUCTION Glufosinate resistant (GR) buffalo grasses were genetically modified to resist the b... more INTRODUCTION Glufosinate resistant (GR) buffalo grasses were genetically modified to resist the broad-spectrum herbicide, glufosinate by inserting a novel pat gene into its genome. This modification results in a production of additional phosphinothricin acetyltransferase (PAT) to detoxify the deleterious effects of glufosinate. The GR grasses and its associated herbicide form a modern, weeding program, to eradicate obnoxious weeds in turf lawn without damaging the grasses at relatively low costs and labor. As with several principal crops which are genetically modified to improve agricultural traits, biosafety of the GR buffalo grasses is inevitably expected to become a public concern. For the first time, we had previously examined the metabolome of glufosinate-resistant buffalo grasses, using a GC-MS untargeted approach to assess the risk of GR as well as identify any pleotropic effects arising from the genetically modification process. In this paper, an untargeted high-resolution L...

Research paper thumbnail of Algae: an essential link between our past and future

Microbiology Australia

Interest in the replacement of imported fossil-based fuels with home-grown, renewable and cheap s... more Interest in the replacement of imported fossil-based fuels with home-grown, renewable and cheap sources of energy spikes each time we are paying over $1.50/litre for petrol. This time, however, the danger of an energy shortage coincides with an increasing level of atmospheric CO2 and an approaching global food shortage. This all dictates an urgency for the development of a new generation of feedstocks that will not only produce biofuels or their various components, but that can also be used for feeding animals and humans and at the same time will reduce a level of atmospheric CO2. These feedstock organisms have to be grown on marginal lands not used for food crops and require low inputs of fresh water and fertiliser. Further adding to this wish list is that these feedstocks could also grow in sea water, can utilise animal and human waste and be used as fertilisers for crops. All of this will finish a portrait of algae, a group of aquatic, photosynthetic, organisms ranging in size fr...

Research paper thumbnail of Utilization of GC–MS untargeted metabolomics to assess the delayed response of glufosinate treatment of transgenic herbicide resistant (HR) buffalo grasses (Stenotaphrum secundatum L.)

Research paper thumbnail of Mutations in humans and animals which affect copper metabolism

Journal of Inherited Metabolic Disease, Feb 1, 1983

Research paper thumbnail of Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells

Biotechnology for biofuels, 2015

Numerous strategies have evolved recently for the generation of genetically modified or synthetic... more Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive. This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its geneticall...

Research paper thumbnail of Molecular Biology of Flavonoid Pigment Biosynthesis in Flowers

Plant Gene Research, 1991

Go to AGRIS search. Molecular biology of flavonoid pigment biosynthesis in flowers. Stevenson, TW... more Go to AGRIS search. Molecular biology of flavonoid pigment biosynthesis in flowers. Stevenson, TW (Calgene Pacific Pty Ltd., Victoria, Australia). ... Source, Molecular approaches to crop improvement, Dennis, ESLlewellyn, DJ (eds.), [nd].- ISBN 03-878-22305. p. 127-148. ...

Research paper thumbnail of Gene Flow and Risk Assessment in Genetically Modified Crops

Alien Gene Transfer in Crop Plants, Volume 1, 2013

Research paper thumbnail of Production and characterisation of transgenic cauliflower plants containing abnormal chloroplasts

Scientia Horticulturae, 2013

Research paper thumbnail of Isolation and characterisation of a cDNA clone encoding cinnamyl alcohol dehydrogenase in Eucalyptus globulus Labill

Plant Science, 1999

Cinnamyl alcohol dehydrogenase (CAD) (EC 1.1.1.195) catalyses the final step in lignin precursor ... more Cinnamyl alcohol dehydrogenase (CAD) (EC 1.1.1.195) catalyses the final step in lignin precursor synthesis reducing the cinnamyl aldehydes (para-coumaryl, coniferyl and sinapyl aldehydes) to the corresponding alcohols in the presence of NADPH. In this paper, we report the molecular cloning and characterisation of a Eucalyptus globulus genomic fragment encoding CAD2, and the corresponding full-length cDNA isolated from young stem material. This was achieved using the polymerase chain reaction-based method known as rapid amplification of cDNA ends, with oligonucleotide primers corresponding to regions of homology between CAD-encoding sequences from other eucalypt species. The identity of the clones was inferred by sequence data comparison and the cDNA sequence (1423 bp) was found to encode a protein of 356 amino acid residues. The CAD2 transcript was most abundant in stem, followed by root and midrib tissues, which corresponds with the role of lignin in water retention in plants and in providing mechanical support. Low level expression was also observed in leaf tissue. Southern blot analysis revealed a single CAD gene in this species with the presence of possibly different allelic representations.

Research paper thumbnail of Mutations in humans and animals which affect copper metabolism

Journal of Inherited Metabolic Disease, 1983

Research paper thumbnail of Dual application of duckweed and azolla plants for wastewater treatment and renewable fuels and petrochemicals production

Biotechnology for Biofuels, 2014

Background: Shortages in fresh water supplies today affects more than 1 billion people worldwide.... more Background: Shortages in fresh water supplies today affects more than 1 billion people worldwide. Phytoremediation strategies, based on the abilities of aquatic plants to recycle nutrients offer an attractive solution for the bioremediation of water pollution and represents one of the most globally researched issues. The subsequent application of the biomass from the remediation for the production of fuels and petrochemicals offers an ecologically friendly and cost-effective solution for water pollution problems and production of value-added products. Results: In this paper, the feasibility of the dual application of duckweed and azolla aquatic plants for wastewater treatment and production of renewable fuels and petrochemicals is explored. The differences in absorption rates of the key wastewater nutrients, ammonium and phosphorus by these aquatic macrophytes were used as the basis for optimization of the composition of wastewater effluents. Analysis of pyrolysis products showed that azolla and algae produce a similar range of bio-oils that contain a large spectrum of petrochemicals including straight-chain C10-C21 alkanes, which can be directly used as diesel fuel supplement, or a glycerin-free component of biodiesel. Pyrolysis of duckweed produces a different range of bio-oil components that can potentially be used for the production of "green" gasoline and diesel fuel using existing techniques, such as catalytic hydrodeoxygenation. Conclusions: Differences in absorption rates of the key wastewater nutrients, ammonium and phosphorus by different aquatic macrophytes can be used for optimization of composition of wastewater effluents. The generated data suggest that the composition of the petrochemicals can be modified in a targeted fashion, not only by using different species, but also by changing the source plants' metabolic profile, by exposing them to different abiotic or biotic stresses. This study presents an attractive, ecologically friendly and cost-effective solution for efficient bio-filtration of swine wastewater and petrochemicals production from generated biomass.

Research paper thumbnail of Copper induction of translatable metallothionein messenger RNA

Bioscience Reports, 1981

Copper chloride injection of rats resulted in a 4.5- to 9-fold increase in translatable metalloth... more Copper chloride injection of rats resulted in a 4.5- to 9-fold increase in translatable metallothionein messenger RNA in the liver. Metallothionein in the translation products was identified on the basis of high cysteine and serine incorporation and absence of leucine incorporation as well as comigration with authentic zinc-induced rat-liver metallothionein on SDS-polyacrylamide gels.

Research paper thumbnail of Co-expression of microbial cellulases in transgenic wheat as a potential source for cellulosic ethanol production

Crop residues are produced in abundance in agriculture and forestry and are a potential source of... more Crop residues are produced in abundance in agriculture and forestry and are a potential source of lignocellulosic biomass for ethanol production. Recent research has included the heterologous expression in transgenic plants of genes encoding cellulases to produce fermentable sugars from plant biomass. In this study, transgenic wheat lines were generated co-expressing the genes for an endoglucanase 1 (E1) of Acidothermus cellulolyticus and cellobiohydrolase 1 (CBH1) of Trichoderma reesei. Both genes were under the control of a wheat Rubisco small subunit promoter (RbcS). Transgenic wheat leaves accumulated apoplast targeted E1 and CBH1 proteins at levels up to 1 and 0.5% respectively of total soluble protein as determined by immunoblotting. Transgenic plants co-expressing E1 and CBH1 were analysed by a 4-methylumbelliferyl-β-D-cellobioside (MUC) assay and enzymatic activity was detected up to 92 nmol 4-MU/mg tsp/min.

Research paper thumbnail of Characterization of Flavonoid 3',5'Hydroxylase in Microsomal Membrane Fraction of Petunia hybrida Flowers

We have detected a flavonoid 3',5'-hydroxylase (F3',5'H) in the microsomal fracti... more We have detected a flavonoid 3',5'-hydroxylase (F3',5'H) in the microsomal fraction of Petunia hybrida flowers. Activity varied with the development of flowers, peaking immediately prior to and during anthesis, but was absent in mature flowers. F3',5'H activity in flower extracts from genetically defined floral color mutants correlated strictly with the genotypes Hfl and Hf2. No activity was detected in flowers

Research paper thumbnail of Developmental variation in copper, zinc and metallothionein mRNA in brindled mutant and nutritionally copper deficient mice

Biochimica Et Biophysica Acta-molecular Basis of Disease, 1991

The concentrations of copper, zinc and metallothionein-I (MT-I) mRNA were determined in the liver... more The concentrations of copper, zinc and metallothionein-I (MT-I) mRNA were determined in the liver, kidney and brain of the brindled mutant mouse from birth until the time of death. Despite accumulation of copper in the kidney of the mutant, MT-I mRNA concentrations were normal. There was no difference between the MT-I mRNA in the brain of mutant and normal in the first 10 days of life, but after day 10 metallothionein mRNA levels were increased in the mutant. The concentration of copper was very low in the liver of the mutant, and on day 6 after birth the metallothionein mRNA was also reduced by about 50%. This reduction was not seen in copper-deficient 6-day-old pups, despite very low hepatic copper levels. This suggests that the lower hepatic MT-I mRNA in the day 6 brindled mouse was not simply due to the reduction in hepatic copper and also that hepatic copper is not regulating metallothionein gene expression the liver of neonatal mice. After day 12 hepatic MT-I mRNA levels were elevated in mutant and in copper deficient mice, both of which die at 14 to 16 days. These increases and the increase in brain MT-I mRNA in older mutant mice are likely to be caused by stress. Overall the results support the conclusions that the brindled mutation does not cause a constitutive activation of the metallothionein genes, and that the differences in metallothionein mRNA between mutant and normal are most probably secondary consequences of the mutation.

Research paper thumbnail of Fungal-assisted algal flocculation: application in wastewater treatment and biofuel production

Biotechnology for Biofuels, 2015

Background: The microalgal-based industries are facing a number of important challenges that in t... more Background: The microalgal-based industries are facing a number of important challenges that in turn affect their economic viability. Arguably the most important of these are associated with the high costs of harvesting and dewatering of the microalgal cells, the costs and sustainability of nutrient supplies and costly methods for large scale oil extraction. Existing harvesting technologies, which can account for up to 50% of the total cost, are not economically feasible because of either requiring too much energy or the addition of chemicals. Fungal-assisted flocculation is currently receiving increased attention because of its high harvesting efficiency. Moreover, some of fungal and microalgal strains are well known for their ability to treat wastewater, generating biomass which represents a renewable and sustainable feedstock for bioenergy production.

Research paper thumbnail of Application of Aquatic Plants for the Treatment of Selenium-Rich Mining Wastewater and Production of Renewable Fuels and Petrochemicals

Journal of Sustainable Bioenergy Systems, 2014

Aquatic plants aggressively colonising wetlands are widely used for the biosorption of the solubl... more Aquatic plants aggressively colonising wetlands are widely used for the biosorption of the soluble contaminants from wastewater and represent an attractive feedstock for biofuel production. Three common Australian aquatic plants, duckweed (Landoltia punctata), elodea, (Elodea canadensis) and water clover (Marsilea quadrifolia), colonizing different depths of wetlands were tested for their ability to treat the selenium-rich mining wastewater and for their potential for production of petrochemicals. The results showed that these plants could be effective at biofiltration of selenium and heavy metals from mining wastewater accumulating them in their fast growing biomass. Along with production of bio-gas and bio-solid components, pyrolysis of these plants produced a range of liquid petrochemicals including straight-chain C14-C20 alkanes, which can be directly used as a diesel fuel supplement or as a glycerine-free component of biodiesel. Other identified bio-oil components can be converted into petrochemicals using existing techniques such as catalytic hydrodeoxygenation. A dual application of aquatic plants for wastewater treatment and production of value-added chemicals offers an ecologically friendly and cost-effective solution for water pollution problems and renewable energy production.