Production of Ligninolytic Enzymes by Coptotermes curvignathus Gut Bacteria

Abstract

Maximum utilization of lignocellulosic biomass is contingent upon degrading the recalcitrant lignin polymer. Conventional methods employed in delignification require high inputs of energy and chemicals, resulting in the release of highly toxic effluents. The ability of gut flora of Coptotermes curvignathus in lignin degradation was investigated in this study. Production of ligninolytic enzymes was done in an aerated submerged fermentation system with kraft lignin as sole carbon source. The degradation experiment was carried out for 7 days at 30 °C, pH 7. Three potential lignin degraders identified as Bacillus sp., Lysinibacillus sp. and Acinetobacter sp. were successfully isolated. The bacterial growth and secretion of extracellular ligninolytic enzymes confirmed metabolism of kraft lignin by the identified strains. Lysinibacillus sp., a novel lignin degrader showed highest manganese peroxidase (76.36 ± 15.74 U/L) and laccase activity (70.67 ± 16.82 U/L) after 7 and 6 days of incubation respectively, while maximal activity of lignin peroxidase (262.49 ± 0.92 U/L) was recorded after 7 days in culture supernatants of Bacillus sp. With respect to the activity of the secreted enzymes, the lignin degrading potential of these bacterial strains can be explored in the valorisations of lignocellulosic biomass in industrial processes such as pulping, bioethanol production, fine chemicals and materials synthesis.

Biodelignification of lignocellulose using ligninolytic enzymes from white-rot fungi

“…A recent study reporting activity of MnP from bacterial isolated from the digestive tract of Coptotermes curgnathus, especially Bacillus sp., Lysinibacillus sp., and Acinetobacter sp. Lysinibacillus showed the highest MnP activity after 7 days of cultivation [114], and followed by Bacillus aryabhattai that isolated from a liquid waste of pulp and paper fabrics. Bacillus pumilus [113] Lysinibacillus sp.…”

Unlocking the potential of insect and ruminant host symbionts for recycling of lignocellulosic carbon with a biorefinery approach: a review

“…Gut bacterial isolates namely Bacillus safensis DSKK5, Lysinibacillus sp., (novel), Acinetobacter sp., and Bacillus sp., from earthworm and Coptotermes curvignathus are the potential ligninase producer under submerged fermentation. Among them, the novel lignin degrader ( Lysinibacillus sp.,) showed a maximum activity of about 70.67 ± 16.82 U/L and 76.36 ± 15.74 U/L of laccase and manganese peroxidase, respectively [ 62 , 63 ].…”

Multi-Criteria Analysis of Lignocellulose Substrate Pre-Treatment

“…Although fungi as decomposes are well known, there has been proof that bacteria could be used for decomposition of lignin as well. Due to natural abilities of bacteria to break the lignocellulose down fast, they have been used for enzyme production itself [23]. Moreover, in addition to lignin peroxidase, manganese peroxidase and laccase can be found in bacteria.…”