Extracellular hydrolase profiles of fungi isolated from koala faeces invite biotechnological interest
Robyn Peterson & Jasmine Grinyer & Helena Nevalainen
Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
The extracellular enzymes of seven fungal strains isolated from koala faeces have been comprehensively characterised for the first time, revealing potential for biotechnological applications. The fungal isolates were grown in a hydrolase-inducing liquid medium and the supernatants were analysed using enzyme assays and zymogram gels. Temperature and pH profiles were established for xylanase (EC 18.104.22.168 endo-1,4-β-xylanase), mannanase (EC 22.214.171.124 mannan endo-1,4-β-mannosidase), endoglucanase (EC 126.96.36.199 cellulase), β-glucosidase (EC 188.8.131.52 β-glucosidase), amylase (EC 184.108.40.206 ∝- amylase), lipase (EC 220.127.116.11 triacylglycerol lipase) and protease (EC 3.4 peptidase) activities. Comparisons were made to the high-secreting hypercellulolytic mutant strain Trichoderma reesei RUT-C30 and the wild-type T. reesei QM6a. The isolates from koala faeces Gelasinospora cratophora A10 and Trichoderma atroviride A2 were good secretors of total protein and heat-tolerant enzymes. Doratomyces stemonitis C8 secreted hemicellulase(s), endoglucanase(s) and β-glucosidase(s) with neutral to alkaline pH optimums. A cold-tolerant lipase was secreted by Mariannaea camptospora A11. The characteristics displayed by the enzymes are highly sought after for industrial processes such as the manufacture of paper, detergents and food products. Furthermore, the enzymes were produced at good starting levels that could be increased further by strain improvement programs.