Multifarious activities of cellulose degrading bacteria from Koala (Phascolarctos cinereus) faeces
Singh, S, Thavamani, P, Megharaj, M & Naidu, R 2015, Journal of Animal Science and Technology, vol. 57, no. 3, pp. 1-6.
The most common bacteria found in koala faeces are Bacillus sp. and Pseudomonas sp. after isolation using carboxymethylcellulose-Congo red agar and hydrolytic enzyme activity screening in vitro. There were high activity levels for several enzymes, including xylanase, lignin peroxidase and amylase, with lower concentrations of endoglucanase activity. The isolates were also able to grow in the presence of phenanthrene, suggesting possible applications in bioremediation.
The findings noted a cellulose degrading bacterium at a concentration of 4.4 x 10^8 colony forming units per gram of koala faeces. Researchers selected ten different colonies for further study, with 40% showing xylanase, lignin peroxidase and amylase activity. KC2 was an active endoglucanase producer with a hydrolysis capacity index of 6.86. KC4 had good xylanase activity (HCI of 4.37), and KC8 was a strong tannase producer (HCI of 3.95). KC10 showed the maximum proteolytic activity with an HCI of 4.12, while KC4 was the only colony to not show proteolytic activity, in addition to a lack of lipase, lignin peroxidase and tannase activity. Eight of the ten cultures grew on phenanthrene cultures, a pollutant considered as toxic and carcinogenic. RNA sequencing revealed that six of the colonies were bacteria from the Bacillus genus and four were Stenotrophomonas.
Previous studies have looked at the microflora of the koala intestine, but very few have looked at bacteria remaining in the faeces. The phyla found in koala faeces, firmicutes (Bacillus) and gamma proteobacteria (Stenotrophomonas), are commonly isolated from both intestinal and faecal samples from other species. The Bacillus genus, in particular, is often found in vertebrate faeces, supporting the data gained through this study.
Greater knowledge of the bacteria in koala faeces and intestines provides an increased understanding of the digestive process and metabolism in koalas, which in turn improves information on their dietary requirements and behaviour.
Summarised by Laura Wait
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