Main content area

Cloning and characterization of a modular GH5 β-1,4-mannanase with high specific activity from the fibrolytic bacterium Cellulosimicrobium sp. strain HY-13

Kim, Do Young, Ham, Su-Jin, Lee, Hyun Ju, Cho, Han-Young, Kim, Ji-Hoon, Kim, Yi-Joon, Shin, Dong-Ha, Rhee, Young Ha, Son, Kwang-Hee, Park, Ho-Yong
Bioresource technology 2011 v.102 no.19 pp. 9185-9192
Cellulosimicrobium, Eisenia fetida, Escherichia coli, Micromonospora, active sites, bacteria, catalytic activity, chitin, chitosan, curdlan, enzymes, feed additives, genes, lignin, livestock and meat industry, locust bean gum, mannans, nuts, oats, sugars, xylan
The gene (1272-bp) encoding a β-1,4-mannanase from a gut bacterium of Eisenia fetida, Cellulosimicrobium sp. strain HY-13 was cloned and expressed in Escherichia coli. The recombinant β-1,4-mannanase (rManH) was approximately 44.0kDa and has a catalytic GH5 domain that is 65% identical to that of the Micromonospora sp. β-1,4-mannosidase. The enzyme exhibited the highest catalytic activity toward mannans at 50°C and pH 6.0. rManH displayed a high specific activity of 14,711 and 8498IUmg⁻¹ towards ivory nut mannan and locust bean gum, respectively; however it could not degrade the structurally unrelated polysaccharides, mannobiose, or p-nitrophenyl sugar derivatives. rManH was strongly bound to ivory nut mannan, Avicel, chitosan, and chitin but did not attach to curdlan, insoluble oat spelt xylan, lignin, or poly(3-hydroxybutyrate). The superior biocatalytic properties of rManH suggest that the enzyme can be exploited as an effective additive in the animal feed industry.