Isolation and Identification of Cellulolytic Bacteria Symbiont from Various Termites on Different Nest Type in Bukit Baka Bukit Raya National Park, West Kalimantan, Indonesia

Abstract

The microbial symbiotic community in the digestive tract of termites is reportedly influenced by the taxonomy and feeding habit of the host. Both factors are strongly correlated with the nest type. This study aimed to isolate the cellulolytic bacteria from termite’s digestive tract on different nest types and characterize and identify the potential isolates. The research methods included termite sampling conducted in Bukit Baka Bukit Raya National Park (BBBRNP), Melawi, West Kalimantan, isolation of cellulolytic bacteria from termites’ gut, endoglucanase activity test, biochemical characterization, and DNA analysis based on the amplification of 16S rRNA gene. Thirty isolates from 6 different species of termites on three different nest types were successfully isolated. Sixteen potential endoglucanase bacterial isolates were tested in terms of their endoglucanase activity. The cellulolytic index measured from those isolates ranged from 1.162 - 4.894. Three isolates (MRH.13.S, MRH.13.AF, and MRH.13.O2) with the highest cellulolytic index on each nest type were identified. The analysis of 16S rRNA gene using BLAST (Basic Local Alignment Search Tool for Nucleotides) revealed that isolate MRH.13.S had the closest relationship with Bacillus tequilensis (99 % homology). Based on biochemical characterization, MRH.13.AF and MRH.13.O2 isolates were related to Bacillus spp. HIGHLIGHTS Potential cellulolytic bacteria from termite intestinal tract from different nests (i.e., soil, wood, and arboreal) were isolated and compared Termites were obtained from a lowland dipterocarp primary forest ecosystem in Bukit Baka Bukit Raya National Park, West Kalimantan Province, Indonesia Termite species collected were Termes comis, Dicuspiditermes garthwaitei, Synhamitermes quadriceps, Havilanditermes proatripennis, Bulbitermes borneensis, and Bulbitermes parapusillus Potential cellulolytic bacteria acquired were closely related with Bacillus tequilensis and Bacillus spp GRAPHICAL ABSTRACT

Cellulolytic activity of bacteria from the gut of termites (Macrotermes michaelseni) from Eldoret and Kakamega

“…However, the highest cellulolytic index (3.50) value reported in their study was lower than the one obtained from this study. Another study by Hidayat (2021) obtained similarly cellulolytic index results ranging from 1.16 to 4.89 as obtained from this study.…”

“…Cellulolytic bacteria produce cellulases enzymes that break down the glycosidic bonds between cellulose microfibrils, releasing oligosaccharides and improving cellulose digestion (Hidayat, 2021). This enzyme aids in the breakdown of complex cellulose compounds into smaller molecules, allowing bacteria to digest them (Peristiwati and Herlini, 2018).…”

“…All plates were screened using 1% carboxymethyl cellulose media to test the isolates' cellulolytic capability, as described above. The presence of endoglucanase was demonstrated by the creation of a clear zone after pouring gram's iodine (Hidayat, 2021).…”

“…This was achieved by dividing the diameter of the clear zone by the diameter of the colony. According to Hidayat (2021), isolates with cellulolytic index greater than 1.50 are regarded as potential cellulose producers. The cellulolytic index of the 17 isolates that formed clear zone around their colony varied from one organism to another.…”

Cellulolytic and Ethanologenic Evaluation of Heterotermes indicola’s Gut-Associated Bacterial Isolates

“…93,94 The isolates possessing cellulolytic index higher than 1.5 or 2.0 may be considered as an efficient cellulase producer. 77 These findings corroborated with the cellulolytic index reported by Kakkar et al 69 in gut bacteria from Odontotermes parvidens, Raheli et al 25 in Macrotermes michaelseni, and in different termites. 77 The bacterial strains isolated for the current study had efficient cellulase producers to convert cellulosic microfibrils into oligosaccharides and monosaccharides.…”