Bioethanol production from urban cellulosic waste employing Alcaligenes faecalis HI-1 isolated from gut of termite Heterotermes indicola

This study assessed the potential of termite gut inhabiting bacteria towards bioconversion of cellulosic waste into biofuel. Total seven bacterial isolates from the gut of Heterotermes indicola were isolated. Among all the isolates, HI-1 produced the largest zone upon primary screening. Untreated paper had more cellulose content (73.03%) than acid (0.5%) treated paper that was used as a lignocellulosic substrate for saccharification. Among all the isolates tested, glucose yield (1.08mg/mL) was high for HI-1 isolate. Several factors were considered for optimizing augmented glucose yield (8.57mg/mL) and growth (8.07×108cfu/mL), such as temperature 37°C, pH 4.5, 5% (w/v) substrate concentration, 6 % bacterial inoculum size, agitation 150 rpm with PEG 0.25 % and Ca2+ ions 0.002 g/L. Overall 8-fold increase in glucose yield was achieved. Enzyme activity of HI-1 showed higher endoglucanase 0.29 ± 0.01 (U/mL/min) and exoglucanase 0.15±0.01 (U/mL/min) activity under optimum conditions, mentioned above. temperature 37°C, pH 4.5, substrate concentration 5%, inoculum size 6%, surfactants PEG 0.01%, ions Ca2+(0.002g/L) and agitation (120 rpm). Simultaneous saccharification and fermentation (SSF) of hydrolyzed office paper yielded 5.43mg/mL bioethanol. According to 16S rRNA sequence homology, the bacterial isolate H1 was identified as Alcaligenes faecalis. Bioethanol production from office paper untreated waste proved an effective strategy. Bacteria having natural tendency towards cellulosic waste consumption are promising for bioconversion of cellulosic waste to valuable products.

Inter and intra termites colonies comparisons of gut microbial diversity from worker and soldier caste of Globitermes sulphureus (Blattodea: Termitidae) using 16S rRNA gene

Aims: The present study aims at isolation and identifying termite gut bacteria from different Globitermes sulphureus mounds using a molecular approach based on16S rRNA genes. Methodology and results: The bacteria from the whole gut of soldier and worker castes of the termite G. sulphureus was isolated and identified. The diversity of the bacteria was compared between five different colonies in Universiti Sains Malaysia, Penang, Malaysia. The isolated bacteria were identified by using 16S rRNA gene sequencing method and subsequently used for phylogenetic analysis. Sequences analyses of identified bacteria were found to be affiliated with the phyla Firmicutes, Proteobacteria, and Actinobacteria. Soldiers and workers seemed to have little differences in bacterial species from the same colonies. We noted some bacteria which were detected in soldiers were not detected in workers. Conclusion, significance and impact of study: Differences in the culturable bacteria composition were not significant between termite colonies. However, the phylogenetic analysis revealed that most of the bacteria from one colony were slightly but distinctly different with bacteria from other colonies.

Isolation and Characterization of Cellulase Producing Bacteria from the Gut of Termites (Odontotermes and Heterotermes Species).

Aim: To identify, characterize and compare the cellulolytic potentials of strains isolated from the gut of Odontotermes and Heterotermes species. Methodology: Termites were collected, identified, surface sterilized and used as source of cellulase producers. Enrichment of cellulose utilizers were done using liquid media containing carboxy methyl cellulose (CMC) as the sole source of carbon and their cellulolytic potentials were confirmed using congo red plate screening method. The isolates showing considerable zone of clearance were biochemically characterized. Three effective isolates were further identified by 16S rRNA gene sequence analysis. Growth curves of the strains were constructed under six different conditions (static and shaking at 25°C, 37°C and 45°C). Their cellulase activities- endoglucanase, FPase and β-glucosidase, assayed at 18 hours of incubation were compared under the above mentioned conditions. Results: Five isolates showing significant zone of clearance were selected, out of which three belonged to Bacillus and one each to Staphylococcus and Enterobacter sp. The three Bacillus sp. which were dominant cellulase producers were found to belong to Bacillus cereus (strain HT from Heterotermes sp. and ODO1, ODO2 from Odontotermes sp.). All the isolates showed high growth at 37°C under shaker condition. Bacillus cereus ODO2 displayed a higher cellulolytic potential compared to strain HT and ODO1. The endoglucanase, FPase and β-glucosidase activities of ODO2 were 5.06 U/mg, 2.52 U/mg and 6.01 U/mg respectively. ODO2 showed optimum specific activity at 37°C in shaker condition, whereas ODO1 and HT preferred static at same temperature. Conclusion: The strains obtained in the present study are potent cellulase producers and thus can find application in food, animal feed, textile, fuel and chemical industries. Optimization of media and genetic modification of the strains can further improve their efficiency. All the three isolates are promising in view of use in future.

Insect gut microbiome - An unexploited reserve for biotechnological application

Metagenomics research has been developed over the past decade to elucidate the genomes of the uncultured microorganisms with an aim of understanding microbial ecology. On the other hand, it has also been provoked by the increasing biotechnological demands for novel enzymes, antibiotic and signal mimics. The gut microbiota of insects plays crucial roles in the growth, development and environmental adaptation to the host insects. Very recently, the insect microbiota and their genomes (microbiome), isolated from insects were recognized as a major genetic resources for bio-processing industry. Consequently, the exploitation of insect gut microbiome using metagenomic approaches will enable us to find novel biocatalysts and to develop innovative strategies for identifying smart molecules for biotechnological applications. In this review, we discuss the critical footstep in extraction and purification of metagenomic DNA from insect gut, construction of metagenomic libraries and screening procedure for novel gene identification. Recent innovations and potential applications in bioprocess industries are highlighted.

Insect gut microbiome - An unexploited reserve for biotechnological application

Metagenomics research has been developed over the past decade to elucidate the genomes of the uncultured microorganisms with an aim of understanding microbial ecology. On the other hand, it has also been provoked by the increasing biotechnological demands for novel enzymes, antibiotic and signal mimics. The gut microbiota of insects plays crucial roles in the growth, development and environmental adaptation to the host insects. Very recently, the insect microbiota and their genomes (microbiome), isolated from insects were recognized as a major genetic resources for bio-processing industry. Consequently, the exploitation of insect gut microbiome using metagenomic approaches will enable us to find novel biocatalysts and to develop innovative strategies for identifying smart molecules for biotechnological applications. In this review, we discuss the critical footstep in extraction and purification of metagenomic DNA from insect gut, construction of metagenomic libraries and screening procedure for novel gene identification. Recent innovations and potential applications in bioprocess industries are highlighted.

DGGE detection and screening of lignocellulolytic bacteria from the termite gut of Coptotermes formosanus

Aims: Termites thrive in terrestrial ecosystems and play an important role in the bio-recycling of lignocellulose. The objective of this study is to isolate and detect bacteria from the termite gut of Coptotermes formosanus and to screen their various enzyme activities by qualitative methods. In addition, this study was aimed to isolate lignin and furfural tolerant strains for various industrial bioprocesses. Methodology and Results: In this study, 50 worker termites of Coptotermes formosanus were collected from dead trees, from a forest in Taichung, Taiwan in June 2008 and the composition of the microbial flora from the termite guts was analyzed by DGGE analysis. The results proved that anaerobic and facultatively anaerobic bacteria consisting of Acinetobacter, Bacteroides thetaiotaomicron, Escherichia coli, and Caulobacter readily existed in the guts of termites. Although the majority of these gut symbionts have not yet been cultivated or identified, some related bacteria were isolated. Two isolates 1-8 and 2-2 of Genus Bacillus, exhibited endocellulase, protease, lipase, amylase, peroxidase and lignin peroxidase activity. Under aerobic conditions, the growth density of isolate 1-8 cultured in 1000 ppm lignin containing MSM medium was two-folds higher than cultured in MSM medium without lignin. Furthermore, the isolate 1-8 was tolerant to 20 mM furfural supplemented in the MSM medium. HPLC analysis confirmed Bacillus isolate 1-8 could degrade up to 15 mM furfural. Conclusion, significance and impact of study: Hind gut bacteria from C. formosanus were detected by culture independent DGGE method. Also, Bacillus isolates 1-8 and 2-2 obtained by culture dependent methods could withstand higher concentration of furfural and as well as lignin. These isolates may be co-cultured with ethanologenic bacteria and be used as an industrial biocatalyst for biofuel production.