biostudies-literatureUnknown9Sadaqat B<i>Thermotoga maritima</i> (<i>Tma</i>) contains genes encoding various hyperthermophilic enzymes with great potential for industrial applications. The gene TM1752 in <i>Tma</i> genome has been annotated as cellulase gene encoding protein Cel5B. In this work, the gene TM1752 was cloned and expressed in <i>Escherichia coli</i>, and the recombinant enzyme was purified and characterized. Interestingly, the purified enzyme exhibited specific activities of 416 and 215 U/mg on substrates galactomannan and carboxy methyl cellulose, which is the highest among thermophilic mannanases. However, the putative enzyme did not show sequence homology with any of the previously reported mannanases; therefore, the enzyme Cel5B was identified as bifunctional mannanase and cellulase and renamed as Man/Cel5B. Frontiers in bioengineering and biotechnology637649https://www.ebi.ac.uk/biostudies/studies/S-EPMC8007966biostudies-literatureMan/Cel5B, a Bifunctional Enzyme Having the Highest Mannanase Activity in the Hyperthermic Environment.PMC8007966Zuo WShao WRupani PFSadaqat BWang HSha CfalseMan/Cel5B, a Bifunctional Enzyme Having the Highest Mannanase Activity in the Hyperthermic Environment.<i>Thermotoga maritima</i> (<i>Tma</i>) contains genes encoding various hyperthermophilic enzymes with great potential for industrial applications. The gene TM1752 in <i>Tma</i> genome has been annotated as cellulase gene encoding protein Cel5B. In this work, the gene TM1752 was cloned and expressed in <i>Escherichia coli</i>, and the recombinant enzyme was purified and characterized. Interestingly, the purified enzyme exhibited specific activities of 416 and 215 U/mg on substrates galactomannan and carboxy methyl cellulose, which is the highest among thermophilic mannanases. However, the putative enzyme did not show sequence homology with any of the previously reported mannanases; therefore, the enzyme Cel5B was identified as bifunctional mannanase and cellulase and renamed as Man/Cel5B. 2021-01-01T00:00:00Z20212025-04-03T21:04:45.233Z2022-02-09T13:37:43.495ZS-EPMC80079663379650910.3389/fbioe.2021.637649