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Response surface methodology was employed for the optimization of different nutritional and physical parameters for the production of laccase by the filamentous bacteria Streptomyces psammoticus MTCC 7334 in submerged fermentation. Initial screening of production parameters was performed using a Plackett - Burman design and the variables with statistically significant effects on laccase production were identified. Incubation temperature, incubation period, agitation rate, concentrations of yeast extract, MgSO(4)7H(2)O, and trace elements were found to influence laccase production significantly. These variables were selected for further optimization studies using a Box-Behnken design. The statistical optimization by response surface methodology resulted in a three-fold increase in the production of laccase by S. psammoticus MTCC 7334.

Sediment samples were collected from different estuarine and marine areas along the West coast of India. Eighteen actinomycete cultures were isolated using starch casein agar and were screened for polygalacturonase activity by growing them on pectin-agar plates. Clear zones were visualized using 1% cetrimide. Out of the 18 strains screened ten cultures could effect hydrolysis of pectin. The above cultures were subjected to secondary screening under submerged fermentation. The actinomycete strain of Streptomyces lydicus was found to be a potent producer of polygalacturonase. Different growth media were screened for enzyme production and the best medium was selected for further studies. The crude enzyme was used for the treatment of raw banana fibers.

Various process parameters for the production of polygalacturonase by Streptomyces lydicus under solidstate fermentation were optimized. The optimum particle size of wheat bran for polygalacturonase production was in the range of 500-1000 µm. Initial moisture content of 70% was found to be the optimum for enzyme production. The most suitable inoculum size was 1.25 x 10 5 CFU/mL and the optimum incubation temperature was 30ºC. Addition of carbon sources resulted in 37% increase in enzyme yield (425 U/g), whereas no significant enhancement was obtained on nitrogen supplementation. Maximum enzyme yield was recorded at 72 h. When compared to the initial production medium (108.5 U/g), the enzyme yield was 3.9 fold after optimization. Solid-state fermentation was effectively employed to develop a novel process for the simultaneous extraction and degumming of banana fibers. Streptomyces lydicus was allowed to grow on wheat bran medium in which banana leaf sheath pieces were incorporated and the fiber bundles were separated after a two-step fermentative process.

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Response surface methodology (RSM) was employed to establish optimum conditions for enzymatic clarification of sapodilla juice. Polygalacturonase obtained from Streptomyces lydicus had been purified to homogeneity and was used for the treatment. The independent variables were temperature (30-45 degrees C), enzyme concentration (0.5-1.5 U), and treatment time (30-90 min), whose effects on viscosity and clarity of the juice were evaluated using a Box-Behnken design. Significant regression models describing the changes of viscosity and clarity with respect to the independent variables were obtained, with the coefficient of determination, R (2) , greater than 0.8. Based on response surfaces and contour plots, the optimum conditions for clarifying sapodilla juice were enzyme concentration 1.15 U, incubation temperature 34 degrees C, and incubation time 70 min.