Optimization of laccase production from a novel strain-Streptomyces psammoticus using response surface methodology.

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.

Optimization of enzymatic clarification of sapodilla juice: a statistical perspective.

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.

Novel process for the simultaneous extraction and degumming of banana fibers under solid-state cultivation

Various process parameters for the production of polygalacturonase by Streptomyces lydicus under solid-state 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 percent 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 percent 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.

Vários parâmetros de processo de produção de poligalacturonase por Streptomyces lydicus por fermentação em estado sólido foram otimizados. O tamanho ótimo de partícula de farelo de trigo para a produção de poligalacturonase esteve na faixa de 500 a 1000 mm. O teor inicial de umidade de 70 por cento foi o melhor para a produção da enzima. O inóculo inicial mais adequado foi de 1,25 x 10(5) UFC/mL e a temperatura ótima de incubação foi 30ºC. A adição de fontes de carbono resultou em aumento de 37 por cento no rendimento da enzima (425U/g), enquanto que a suplementação com nitrogênio não melhorou o rendimento. O rendimento máximo da enzima foi obtido em 72h. A otimização resultou em um aumento de 3,9 vezes na quantidade de enzima produzida inicialmente (108,5U/g). A fermentação em estado-sólido foi eficiente para o desenvolvimento de um novo processo de extração e simultânea degomagem. Streptomyces lydicus foi cultivado em meio de farelo de trigo acrescentado de fragmentos de folhas de banana, sendo os feixes de fibras separados após um processo de fermentação em dois passos.

Hydrolysis of pectin: an enzymatic approach and its application in banana fiber processing.

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.

Purification and partial characterization of polygalacturonase from Streptomyces lydicus.

Polygalacturonase produced by Streptomyces lydicus was purified to homogeneity by ultrafiltration and a combination of ion exchange and gel filtration chromatographic procedures. The purified enzyme was an exo-polygalacturonase with a molecular weight of 43 kDa. It was optimally active at 50 degrees C and pH 6.0. The enzyme was stable from pH 4.0 to 7.0 and at or below 45 degrees C for 90 min. K(m) value for polygalacturonic acid was 1.63 mg/mL and the corresponding V(max) was 677.8 microM min(-1) mg(-1). The inhibition constant (K(i)) for gluconic acid d-lactone was 20.75 mM. Purified enzyme had been inhibited by N-bromosuccinimide, while l-tryptophan could induce enzyme activity, indicating the involvement of tryptophan at the active site.

Novel process for the simultaneous extraction and degumming of banana fibers under solid-state cultivation.

Various process parameters for the production of polygalacturonase by Streptomyces lydicus under solid-state 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 × 10(5) CFU/mL and the optimum incubation temperature was 30°C. 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.