Journal reference: http://www.biotechnologyforbiofuels.com/content/pdf/1754-6834-6-62.pdf

News release: http://www.tuwien.ac.at/en/news/news_detail/article/8222/

In Vienna, scientists have characterized a mutation in a strain of biomass-degrading fungus that constantly ‘switches on' the production of the desired degrading enzymes even without the inducing factor.

Production of biofuels from lignocellulose materials such as woods and grasses requires the enzymatic breakdown of the long cellulose and xylan components of the biomass into simple fermentable sugars. Industries typically use certain strains of fungi to produce the biomass-degrading cellulase and xylanase enzymes, but only in the presence of a chemical inducer. The high cost of chemical induction somehow pushes up the cost of biofuel manufacturing.

This prompted a research at the Vienna University of Technology seeking to understand the genetic mechanism of regulating the production of cellulase and xylanase in fungus Trichoderma reesei. In one of the T. reesei strains, the researchers found a random mutation that affected the molecular switch linked with the induction mechanism, a gene called xylanase regulator 1 or xyr1. The mutation stopped the chemical switch from functioning so that even without or regardless of an inducer, the fungus always produces the desired enzymes.

Detailed genetic analysis has identified the specific DNA sequence required for this behavior. The findings, published in the journal Biotechnology for Biofuels, open the possibility toward a more directed approach of inducing the same mutation in other fungal strains. Genetic manipulations are now being tested toward further strain engineering to produce even more productive fungi. This would make the production of fuel from lignocellulose more economically attractive.

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Journal reference: http://www.pnas.org/content/early/2013/05/31/1301502110.full.pdf+html

News release: http://www.bbsrc.ac.uk/news/industrial-biotechnology/2013/130603-pr-enzyme-could-turn-waste-into-biofuel.aspx

An international collaboration of scientists has determined the structure and function of a key enzyme used by tiny marine wood borers to break down wood. The findings, published in PNAS, suggest that the unique and robust enzyme offers a potential for producing biofuels from woody biomass.

The researchers studied the enzyme that gives the wood-boring crustacean Limnoria quadripunctata the special ability to thrive on a diet of wood. It has been known that Limnoria have a digestive system free of microbial populations but secrete a class of enzymes that can degrade lignocellulose into simple sugars, which is a key step in bioethanol production.

Using advanced biochemical analysis and X-ray imaging techniques, the Limnoria enzyme, designated as LqCel7B, was found to be a unique cellulase secreted into the gut of the crustacean to function for wood degradation. Detailed characterization also resolved that LqCel7B contains an acidic surface and has the ability to remain stable and active at high salt concentration, making it a candidate enzyme that works under aggressive chemical conditions.

The robust nature of the enzyme makes it compatible for use in conjunction with sea water, which would lower the costs of processing. Lowering the cost of enzymatic processes is critical for making the production of lignocellulosic biofuels cost effective. The robust characteristic would also give the enzyme a longer working life and allow it to be recovered and re-used during processing.

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News release: http://www.theengineer.co.uk/energy-and-environment/news/sound-idea-for-making-plant-biofuels/1016429.article

A study at the Iowa State University has found that ultrasound enhances the chemical reactions necessary to convert biomass feedstock into biofuels.

A team of engineers at ISU has shown that the use of ultrasonics in the pretreatment of a wide variety of feedstocks could increase the efficiency of separating lignin from the biomass so that sugar dissolution could occur in minutes rather than the hours required for traditional pretreatments. Lignin is the tough polymer that binds the complex polysaccharides together in plant cell walls. Lignin prevents access to enzymes that are destined to degrade the polysaccharides, and thus represents an important barrier in the fermentation process that turns simple sugars into biofuel.

The research team has also shown that when corn feedstock is treated with ultrasound rather than cooked with jet steam at extreme temperature, the sonically ground corn particles provided more surface area for enzymatic action, resulting in fermentation yields comparable to output from conventional jet steaming. This finding offers an opportunity to reduce the cost of biofuel production, based on the team's economic analysis.

The study also found the potential of ultrasound to accelerate transesterification, the main chemical reaction for converting oil to biodiesel. The researchers at one point discovered that ultrasound converted soybean oil into biodiesel in less than a minute, rather than the 45 minutes it normally takes. This is said to be faster and a less complicated method than traditional techniques requiring multiple steps and relatively long cycle times.

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News release: https://news.okstate.edu/press-releases/2207-osu-researchers-studying-a-new-method-forbiofuels-production

A research team at the Oklahoma State University has analyzed a fungus that resides in the gut of ruminant animals, revealing more of its characteristics that make it an interesting candidate for biofuel production.

The team has recently analyzed the genome of the rumen fungus and found multiple unique features. Genomic and experimental analyses indicate that the fungus efficiently degrades a wide range of plant biomasss, such as switchgrass, corn stover, sorghum and energy cane. Research interest in this fungus comes from the fact that it can thrive with complete lack of oxygen (anaerobic), has genetically adapted to co-exist with diverse number of bacteria, and has acquired useful genes from these bacteria, including multiple genes that aid in digestion of plant biomass.

Anaerobic fungi are promising agents for consolidating various processes in biofuel production because many of them have concurrent capability to degrade plant biomass (saccharification) and to convert resulting sugars into ethanol (fermentation). OSU researchers are currently looking into this approach as a way to significantly lower the cost of biofuel production.

The next phase of the team's work will be to improve the ratio of ethanol to acids produced by the degradation of plant biomass with this fungus. The fungus currently produces more acids than ethanol as a final product.

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News release: http://www.biosciencetechnology.com/news/2013/06/alkaline-spring-creature-linked-better-biofuels

Teamwork between a professor at Sonoma State University and experts at the Lawrence Berkeley National Laboratory (Berkeley Lab) of the U.S. Department of Energy has led to the isolation of an alkaline tolerant bacterium that has a potential use in biofuel production.

The bacterium was originally isolated from decaying plants in highly alkaline spring water at The Cedars, an isolated area in California's Outer Coast Range, and later identified as a Cellulomonas strain. The strain, now known as FA1, is highly tolerant to alkalinity and can degrade cellulose to produce fermentable sugar in alkaline environment. It can also withstand complete lack of oxygen.

The discovery of FA1 offers an opportunity to widen technological options for non-food biomass based biofuel production. An alkaline tolerant digester will fit well with some of the most effective biomass pretreatment methods that are carried out in alkaline instead of acidic environment.

The FA1 strain, however, has one major drawback – it cannot survive in environment with too much ethanol. The challenge for metabolic engineers is to further modify the microorganism to make it tolerant to high concentrations of ethanol and turn it into an efficient producer of biofuel.