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Background: Lignocellulosic biomass is the most abundant resource on earth. Lignocellulose is mainly composed of cellulose, hemicelluloses and lignin. The special construction of three kinds of constituents led to the prevention of effective degradation. The goal of this work was to investigate the great potentials of bovine rumen for novel cellulolytic bacterial isolation, which may be used for chemicals and biofuel production from lignocellulose. Results: A cellulolytic strain, ZH-4, was isolated from Inner Mongolia bovine rumen. This strain was identified as Escherichia coli by morphological, physiological and biochemical characteristics and 16S rDNA gene sequencing. The extracellular enzyme activity analysis showed that this strain produces extracellular cellulases with an exoglucanase activity of 9.13 IU, an endoglucanase activity of 5.31 IU, and a β-glucosidase activity of 7.27 IU at the pH 6.8. This strain was found to produce 0.36 g/L ethanol and 4.71 mL/g hydrogen from corn straw with cellulose degradation ratio of 14.30% and hemicellulose degradation ratio of 11.39%. Conclusions: It is the first time that a cellulolytic E. coli was isolated and characterized form the bovine rumen. This provided a great opportunity for researchers to investigate the evolution mechanisms of the microorganisms in the rumen and provided great chance to produce biofuels and chemicals directly from engineered E. coli using consolidated bioprocess. [ABSTRACT FROM AUTHOR]

The article presents a study on the immobilization of UDP-galactose 4-epimerase from Escherichia coli on the yeast cell surface. UDP-galactose 4-epimerase from Escherichia coli catalyzes the reversible reaction between UDP-galactose and UDP-glucose. Enzyme activity analyses with EBY100 cells showed that the enzyme displayed on the yeast cell surface was very active in the conversion between UDP-Glc and UDP-Gal.