Category Archives: Biotechnology

Background:
The recalcitrance of lignocellulosic materials is a major drawback for their conversion into fermentable sugars. Lignin depletion in new cultivars or transgenic plants has been identified as a way to diminish this recalcitrance. In this context, a sugarcane breeding program has selected sugarcane plants with low lignin content. The chemical composition and agronomic characteristics of eleven experimental hybrids plus two reference samples are reported. The enzymatic digestion of untreated and chemically delignified samples was evaluated to advance the performance of the sugarcane bagasse in cellulosic-ethanol production processes.
Results:
The glucan, hemicellulose, lignin and extractive contents (based on oven dry biomass) of the experimental hybrids and reference samples varied between 38% and 43%, 25% and 32%, 17% and 24% and 1.6% and 7.5%, respectively. The samples with the smallest amounts of lignin did not present the largest amounts of total polysaccharides. Instead, a flexible distribution of the components, including extractives, seems to compensate for the reduction in lignin content. Hydroxycinnamic acids accounted for a significant part of the aromatic compounds in the samples. P-coumaric acid predominated whereas ferulic acid was detected in low amounts. Hydroxycinnamic acids that were ester-linked to the hemicelluloses varied from 2.3% to 3.6% among the samples. The total amounts of hydroxycinnamic acids that include the fraction linked to lignin through ether linkages varied from 5.0% to 9.2% and correlated, to some extent, with the lignin contents. These clones released up to 31% of glucose after 72h of digestion with commercial cellulases. Chemically delignified samples led to cellulose conversion values higher than 80%. Plants with originally less lignin required lower levels of delignification to reach higher efficiencies of cellulose conversion during the enzymatic treatment.
Conclusion:
Some of the experimental sugarcane hybrids presented combined characteristics of high biomass and sucrose productivities with low lignin contents. Glucan conversion to glucose by commercial cellulases increased in the samples with low lignin content. Chemical delignification further increased the cellulose conversion to values higher than 80%. Interestingly, plants with originally less lignin required lower levels of delignification to reach higher efficiencies of cellulose conversion during the enzymatic treatment.Source:
http://www.biotechnologyforbiofuels.com/rss/

Background:
The optimization of industrial bioethanol production will depend on the rational design and manipulation of industrial strains to improve their robustness against the many stress factors affecting their performance during Very High Gravity (VHG) or lignocellulosic fermentations. In this study, a set of Saccharomyces cerevisiae genes found to confer resistance to the simultaneous presence of different relevant stresses, through genome-wide screenings, were identified as required for maximal fermentation performance under industrial conditions.
Results:
Chemogenomics data were used to identify eight genes whose expression confers simultaneous resistance to high concentrations of glucose, acetic acid and ethanol, chemical stresses relevant for VHG fermentations; and eleven genes conferring simultaneous resistance to stresses relevant during lignocellulosic fermentations. These eleven genes were identified based on two different sets: one with five genes granting simultaneous resistance to ethanol, acetic acid and furfural, and the other with six genes providing simultaneous resistance to ethanol, acetic acid and vanillin. The expression of BUD31 and HPR1 was found to lead to the increase of both ethanol yield and fermentation rate, while PHO85, VRP1 and YGL024w expression is required for maximal ethanol production in VHG fermentations. Five genes, ERG2, PRS3, RAV1, RPB4 and VMA8 were found to contribute to the maintenance of cell viability in wheat straw hydrolysate and/or for maximal fermentation rate of this substrate.
Conclusions:
The identified genes stand as preferential targets for genetic engineering manipulation in order to generate more robust industrial strains, able to cope with the most significant fermentation stresses and, thus, to increase ethanol production rate and final ethanol titers.Source:
http://www.biotechnologyforbiofuels.com/rss/

Background:
Large-scale production of effective cellulose hydrolytic enzymes is the key to bioconversion of agricultural residues to ethanol. The goal of this study was to develop rice plant as a bioreactor for large-scale production of cellulose hydrolytic enzymes via genetic transformation and to improve rice straw simultaneously as an efficient biomass feedstock for conversion of cellulose to glucose.
Results:
In this study, the cellulose hydrolytic enzyme beta-1, 4-endoglucanase (E1) gene, from the thermophilic bacterium Acidothermus cellulolyticus, was overexpressed in rice through Agrobacterium-mediated transformation. The expression of the bacterial E1 gene in rice was driven by the constitutive Mac promoter, a hybrid promoter of Ti plasmid mannopine synthetase promoter and cauliflower mosaic virus 35S promoter enhancer with the signal peptide of tobacco pathogenesis-related protein for targeting the E1 protein to the apoplastic compartment for storage. A total of 52 transgenic rice plants from six independent lines expressing the bacterial E1 enzyme were obtained, which expressed the gene at high levels without severely impairing plant growth and development. However, some transgenic plants exhibited a shorter stature and flowered earlier than the wild type plants. The E1 specific activities in the leaves of the highest expressing transgenic rice lines were about 20 fold higher than those of various transgenic plants obtained in previous studies and the protein amounts accounted for up to 6.1% of the total leaf soluble protein. A zymogram and temperature-dependent activity analysis demonstrated the thermostability of the E1 enzyme and its substrate specificity against cellulose, and a simple heat treatment can be used to purify the protein. In addition, hydrolysis of transgenic rice straw with cultured cow gastric fluid for one hour at 39oC and another hour at 81oC yielded 43% more reducing sugars than wild type rice straw.
Conclusion:
Taken together, these data suggest that transgenic rice can effectively serve as a bioreactor for large-scale production of active, thermostable cellulose hydrolytic enzymes. As a feedstock, direct expression of large amount of cellulases in transgenic rice may also facilitate saccharification of cellulose in rice straw and significantly reduce the costs for hydrolytic enzymes.Source:
http://www.biotechnologyforbiofuels.com/rss/

See the full press release here: bit.ly After an intense day of competition in London, a team of four budding biotechnology entrepreneurs from the University of Oxford have emerged as the winners of this year's Biotechnology Young Entrepreneurs Scheme (YES). The winners of the 2011 Biotechnology Young Entrepreneurs Scheme (YES) competition are Ben Owens, Hannah Richards, Bonnie Murphy and Phillip Wulff from The University of Oxford. See more BBSRC videos here: http://www.bbsrc.ac.uk See BBSRC News for the latest news, features and events: http://www.bbsrc.ac.uk Follow BBSRC on Twitter: twitter.com

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Young science entrepreneurs: Biotechnology YES 2011 - Video

Biology 122 Week15.Lecture1.Part2: Biotechnology, continued

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15.1.2 - Biotechnology, continued - Video

http://www.nucleusinc.com This 3D animation is an example of Nucleus's custom animation projects for biotechnology, showing how the decellularized dermis technology works. For more information, please visit bit.ly

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LifeNet: Matracell Biotechnology - Video