Technology Marketing SummaryThe fermentable fractions of biomass include cellulose and hemicelluloses. The development of an economic process for the conversion of low-value biomass to ethanol via fermentation requires the optimization of several key steps, especially that of cellulase production. Practical utilization of cellulose by hydrolysis with cellulase to produce glucose requires large amounts of cellulase to fully depolymerize cellulose. Economical production of cellulase is compounded by the relatively slow growth rates of cellulase producing fungi and the long times required for cellulase induction. Therefore, improvements in or alternative cellulase production systems capable of greater productivities, higher specific activities of cellulase or faster growth rates than may be possible with natural fungi would significantly reduce the cost of cellulose hydrolysis and make the large-scale bioconversion of cellulosic biomass to ethanol more economical.
DescriptionIt has been proposed to use recombinant cellulase enzymes to either augment or replace costly fungal enzymes for cellulose degradation. Highly thermostable cellulase enzymes are secreted by the cellulolytic thermophile Acidothermus cellulolyticus, which was originally isolated from decaying wood in an acidic, thermal pool at Yellowstone National Park. This endoglucanase demonstrates a temperature optimum of 83 degrees C and a specific activity of 40 micro-mole glucose release from carboxymethylcellulose/min/mg protein. This E1 endoglucanase was further identified as having an isoelectric pH of 6.7 and a molecular weight of 81,000 daltons by SDS-PAGE. The genes coding for Acidothermus cellulolyticus cellulases cloned into other microbial host organisms could provide an abundant, inexpensive source of highly active enzymes.
Benefits- Highly thermostable and resistant to inhibition from cellobiose.
- High specific activity towards cellulose.
- Gene can be cloned into various microorganisms to produce enzyme.
Applications and Industries- Conversion of biomass to fermentable sugars for biofuel production
- Ethanol Production from renewable resources
Patents and Patent Applications
ID Number |
Title and Abstract |
Primary Lab |
Date |
Patent
5,275,944 |
Thermostable purified endoglucanas from acidothermus cellulolyticus ATCC 43068
A purified low molecular weight cellulase endoglucanase I having a molecular weight of between about 57,420 to about 74,580 daltons from Acidothermus cellulolyticus (ATCC 43068). The cellulase is water soluble, possesses both C.sub.1 and C.sub.x types of enzyme activity, a high degree of stability toward heat, and exhibits optimum temperature activity at about 83.degree. C. at pH's from about 2 to about 9, and in inactivation temperature of about 110.degree. C. at pH's from about 2 to about 9. |
National Renewable Energy Laboratory |
01/04/1994
Issued |
Patent
5,536,655 |
Gene coding for the E1 endoglucanase
The gene encoding Acidothermus cellulolyticus E1 endoglucanase is cloned and expressed in heterologous microorganisms. A new modified E1 endoglucanase enzyme is produced along with variants of the gene and enzyme. The E1 endoglucanase is useful for hydrolyzing cellulose to sugars for simultaneous or later fermentation into alcohol. |
National Renewable Energy Laboratory |
07/16/1996
Issued |
Development StagePrototypeAvailabilityAvailablePublished01/14/2010Last Updated02/02/2010
Biomass and Biofuels
