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.

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.

Utilization of rice straw for laccase production by Streptomyces psammoticus in solid-state fermentation.

Laccase production from a novel actinobacterial strain, Streptomyces psammoticus, MTCC 7334 was optimized in solid-state fermentation. The process parameters were initially optimized by the conventional "one factor at a time" approach, and the optimal levels of the factors that had considerable influence on enzyme production were identified by response surface methodology. Rice straw was identified as a suitable substrate for laccase production (17.3 U/g), followed by coffee pulp (15.8 U/g). Other optimized conditions were particle size, 500-1,000 mum (21.2 U/g); initial moisture content, 65% (26.8 U/g); pH of moistening solution, 8.0 (26.9 U/g); incubation temperature, 32 degrees C (27.6 U/g) and inoculum size, 1.5 x 10(7) CFU (33.8 U/g). Yeast extract served as the best nitrogen source (34.8 U/g). No enhancement in enzyme yield was observed with carbon supplementation. The level of yeast extract, inoculum size and copper sulphate were optimized statistically. Statistical optimization performed using a central composite design resulted in threefold increase in laccase activity (55.4 U/g) as compared to the unoptimized medium (17.3 U/g). The upgrading of fermented rice straw for fodder enhancement is also discussed briefly.

Influence of media nutrients on synthesis of lignin peroxidase from Aspergillus sp.

The effect of carbon and nitrogen sources, lignocellulosic substrates, and metal ions on lignin peroxidase (LiP) activity of Aspergillus sp., which was isolated from a mangrove area, was studied. Glucose (1%) was found to be the best carbon source. Among the various lignocellulosic substrates used, coir pith at 3% concentration increased LiP activity twofold on the second day of incubation. Peptone and KNO3 completely inhibited the enzyme synthesis while (NH4)2SO4 at 12.5 mM produced maximum activity. Since seawater contained all the requisite metal ions, any added ions had a negative effect on activity. Cu2+ had the most inhibiting effect while K+ the least. When all the optimized conditions were provided, in nitrogen- and carbon-sufficient medium, a maximum LiP activity of 345 U/mL was obtained on the second day of incubation.