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.

No abstract

Coptotermes curvignathus (C. curvignathus) are subterranean termites that feed on living-tree as their sole diet, which consist mainly of cellulose, hemicelluloses, lignin, plant allele chemical and other environmental residues such as insecticide. The xenobiotic compounds, plant allele chemical and insecticide are hazardous to termites health and need to be transported out of their body via xenobiotic and detoxification metabolism. This paper highlighted the potential enzymes that play vital role in the xenobiotic and detoxification metabolism. Transcriptomic data were generated from 200 termite's digestive system using Illumina HiSeq 2000. Raw data was trimmed and assembled by SOLEXAQA and Bowtie before loaded into Gene Ontology based data mining software, Blast2GO (B2G). The result showed that, C. curvignathus contain enzymes that involved in all three biotransformation phases of xenobiotic and detoxification metabolism, which included cytochrome P450s monooxygenases, glutathione S-transferase, carboxylesterase, UDPglucuronyltransferases and N-acetyltransferase. The result of this study is the first insight into Cc xenobiotic pathway.

The application of ligninolytic bacteria and enzymes is a green pre-treatment alternative in the production of paper and biofuel from oil palm residues. In this study we investigated the ability of Lysinibacillus pakistanensis isolated from termite gut in degrading the lignin component of oil palm residues. The residues were biotreated with the bacterial strain in an aerated submerged fermentation system for 7 days at 30 , pH 7 and compared with untreated control. Enzyme activities were determined using specific substrates. Peak lignin peroxidase (377.6 U/L), manganese peroxidase (218.19 U/L), and laccase (405.4 U/L) activity were recorded after 4,4, and 5 days of incubation respectively, using oil palm leaf as substrates. Lignin loss of 4.5%, 5.7% and 6.6% in oil palm leaf, oil palm trunk and empty fruit bunch respectively was achieved after treatment with the microorganism. SEM images revealed structural changes in the cell wall of the residues. Pre-treatment with this bacterial strain has promising prospects of improving the efficiency of the pulping process in an environmentally safe manner.

No abstract