Production of cell wall-degrading enzymes by a pH tolerant estuarine fungal isolate Fusarium moniliforme NCIM1276 in different culture conditions.

摘要

A pH tolerant strain of Fusarium moniliforme NCIM1276 with a saprophytic mode of nutrition was isolated from a coastal estuarine environment. Under laboratory conditions, the fungus produced significant biomass between pH 3 and 9, and produced cell wall degrading enzymes such as pectinases (polygalacturonase and pectate lyase), carboxymethylcellulase, xylan degrading enzymes and amylase. Production of these enzymes by the isolate in liquid medium, semi-solid medium and infected tomato and cauliflower tissues was investigated. In liquid medium, production of cell wall-degrading enzymes was induced by appropriate substrates, whereas the organism secreted all enzymes constitutively on wheat bran. Production of polygalacturonase, pectate lyase, carboxymethylcellulase, xylan degrading enzymes and amylase was increased by 3, 2, 11, 10 and 4-fold, respectively, with growth on semi-solid medium containing wheat bran and orange pulp. Moreover, fungal infection of tomato and cauliflower plants was localized to their cortical tissues, and secreted pectinases, carboxymethylcellulase and xylan degrading enzymes were present in the infected host tissue.