Super-fermenting fungus genome sequenced

Mar 05, 2007

On the road to making biofuels more economically competitive with fossil fuels, there are significant potholes to negotiate. For cellulosic ethanol production, one major detour has being addressed with the characterization of the genetic blueprint of the fungus Pichia stipitis, by the U.S. Department of Energy Joint Genome Institute and collaborators at the U.S. Forest Service, Forest Products Laboratory.

The research, entailing the identification of numerous genes in P. stipitis responsible for its fermenting and cellulose-bioconverting prowess, and an analysis of these metabolic pathways, is featured in the March 4 advanced online publication of Nature Biotechnology.

P. stipitis is the most proficient microbial fermenter in nature of the five-carbon “wood sugar” xylose—abundant in hardwoods and agricultural leftovers, which represent a motherlode of bioenergy fodder.

“Increasing the capacity of P. stipitis to ferment xylose and using this knowledge for improving xylose metabolism in other microbes, such as Saccharomyces cerevisiae, brewer’s yeast, offers a strategy for improved production of cellulosic ethanol,” said Eddy Rubin, DOE JGI Director. “In addition, this strategy could enhance the productivity and sustainability of agriculture and forestry by providing new outlets for agricultural and wood harvest residues.”

Ligonocellulosic biomass, a complex of cellulose, hemicellulose, and lignin, is derived from such plant-based “feedstocks” as agricultural waste, paper and pulp, wood chips, grasses, or trees such as poplar, recently sequenced by DOE JGI. Under current strategies for generating lignocellulosic ethanol, these forms of biomass require expensive and energy-intensive pretreatment with chemicals and/or heat to loosen up this complex. Enzymes are then employed to break down complex carbohydrate into sugars, such as glucose and xylose, which can then be fermented to produce ethanol. Additional energy is required for the distillation process to achieve a fuel-grade product. Now, the power of genomics is being directed to optimize this age-old process.

“The information embedded in the genome sequence of Pichia has helped us identify several gene targets to improve xylose metabolism,” said Pichia paper lead author Thomas W. Jeffries of the Forest Products Laboratory in Madison, Wisconsin. “We are now engineering these genes to increase ethanol production.” Jeffries said that yeast strains like Pichia have evolved to cope with the oxygen-limited environment rich in partially digested wood that is encountered in the gut of insects, from where the sequenced strain was originally isolated.

FPL has a Cooperative Research and Development Agreement (CRADA) in place with a New York City-based bioenergy company, Xethanol Corporation, which plans to integrate Dr. Jeffries’ findings into its large-scale biofuels production processes.

Source: DOE/Joint Genome Institute

Explore further: Free the seed: OSSI nurtures growing plants without patent barriers

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Plants with dormant seeds give rise to more species

Apr 18, 2014

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers successfully clone adult human stem cells

Apr 18, 2014

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.