ABSTRACT

Cellulose is considered as one of the most abundant polymeric substances found in nature, occurring in all plants and produced by various microorganisms. Bacterial cellulose (BC), an exopolysaccharide produced by bacteria, has unique structural and mechanical properties and is highly pure compared to plant cellulose. An attempt was made to isolate and select the bacterial isolates that produces cellulose. The efficient isolates were grown in different overripe fruit extract for BC production and optimization of growth parameters for maximum BC production was carried out. Eight samples of rotten fruits were taken from local market, Dharwad. A total of 70 bacterial isolates were obtained from all samples using HS media. Screening was carried out to select the best cellulose producing bacterial isolate using HS broth media. The results indicated that only 24 isolates showed the ability to produce bacterial cellulose on HS broth media. The isolates BCI-5, BCI-16 and BCI-22 were superior in their ability to produce bacterial cellulose. Therefore, the native isolates BCI-5, BCI-16 and BCI-22 were chosen as the efficient isolates that produces bacterial cellulose. The study found that a 1:1 pulp concentration across various fruits consistently yielded the highest bacterial cellulose production. Among the tested fruits, banana pulp produced the highest BC yield, followed by papaya, pineapple pulp and coconut water. Based on these results, banana pulp at a 1:1 concentration was chosen for optimization of growth condition of efficient BC producing isolates. During the optimization study, fructose (carbon source), yeast extract (nitrogen source), incubation period of 25 days, inoculum size of 10 %, temperature and pH of 30°C and 6.0, respectively were found to be the optimum parameters for BC production in overripe banana fruit extract. Among the native isolates BCI-5 had produced higher BC yield. Hence the BCI-5, considered as best suited for BC production.