Physical and nutritional factors affecting the production of amylase from species of bacillus isolated from spoiled food waste

Amylase producing Bacillus sp. was isolated from spoiled food waste, which yielded 30 U ml-1 of amylase in medium containing 4% starch and 2% yeast extract at 37°C, pH 7.0 after 20 h of incubation. Maximum amylase activity was at pH 7.0 and 37°C. The enzyme retained 70% activity at pH 9.0. It exhibited 77% activity at 42°C and decreased to a low value of 25% at 52°C proving it as sensitive for temperature. In addition, the identified enzyme showed a maximum activity (32 U/ml) with sodiumdodecyl sulphate compared to other additives. Wheat was found to be a suitable natural source for maximum production of amylase activity. These properties indicated possible use of this amylase in starch saccharification and detergent formulation

Influência do pH e temperatura sobre a atividade amilolítica de rizóbios isolados de solos da Amazônia Influence of pH and temperature on amylolytic activity of rhizobia isolated from Amazonian soils

Poucas são as informações referentes ao perfil enzimático de bactérias rizobiais. Em meio de cultura solidificado, foi conduzido um experimento em fatorial 7 x 3 x 3 para avaliar o efeito do pH (5,0; 6,5 e 8,0) e da temperatura (25, 35 e 42 ºC) sobre a atividade amilolítica de sete isolados de rizóbio. As maiores atividades amilolíticas foram observadas em ambientes ácidos, com algumas bactérias também produzindo níveis significativos em pH 8,0. Entre as interações significativas (P<0,01), os isolados INPA R-110 e R-822 apresentaram máximas atividades em pH 5,0 e 25 ºC, com o R-822 também sendo um bom produtor de amilase nas temperaturas de 35 e 42 ºC. Em termos gerais, os isolados INPA R-110 e R-822 foram os melhores produtores de amilases, com atividades enzimáticas maiores do que 2,0.<br>Information is scarce regarding the enzymatic profiles of rhizobia bacteria. On solid medium, a 7 x 3 x 3 factorial experiment was conducted to evaluate the effect of pH (5.0, 6.5 and 8.0) and temperature (25, 35 and 42 ºC) on amylase activities of seven rhizobia strains. The highest enzymatic activities were found in acid environments, with some bacteria also producing significant levels at pH 8.0. Among the significant interactions (P<0.01), INPA strains R-110 and R-822 exhibited maximum activities at pH 5.0 and 25 ºC, with the R-822 being also a good amylase producer at 35 and 42 ºC. In general terms, INPA strains R-110 and R-822 were the best enzyme producers, with amylolytic enzymatic activities higher than 2.0