Comparative Study on the Ability to Produce Gentiobiose in Cellulose-producing Bacteria Asaia bogorensis and Gluconacetobacter xylinus

Abstract

In a cellulose-producing bacterium Gluconacetobacter xylinus, endo-β-1,4-glucanase and β-glucosidase are suggested to have an important role in cellulose biosynthesis, and genes encoding these enzymes are present adjacent to the cellulose synthesis operon. However, in other cellulose-producing bacteria including Asaia bogorensis, β-glucosidase gene is not found next to the cellulose synthesis operon, and their cellulose productivities are lower than that of G. xylinus. To investigate whether A. bogorensis produces a similar type of β-glucosidase, crude enzyme fractions were prepared from G. xylinus and A. bogorensis. The hydrolytic activities toward p-nitrophenyl-β-D-glycosides were compared. In A. bogorensis, the hydrolytic activities were found in the cytosolic fraction, but the fraction did not indicate an ability to produce gentiobiose that is suggested to be an inducer for expression of the endo-β-1,4-glucanase gene in G. xylinus. We conclude that the mechanism of cellulose biosynthesis regulated by endo-β-1,4-glucanase may be different in A. bogorensis and G. xylinus.