RESUMO
Microbial proteases, especially from Bacillus spp., have been widely exploited for a broad variety of applications, such as the improvement of the cleaning efficiency of conventional detergents. In this work, the statistical design of the experiment was used to optimize the concentrations of a three-component mixture: Bacillus licheniformis SMIA-2 protease, Linear Alkylbenzene Sulphate and hydrogen peroxide, in an attempt to prepare an environmentally correct cleaning formulation. The results demonstrated that the combination of 1% (w/v) protease with 1.5% (w/v) LAS and 1% (w/v) H2O2 was effective in removing blood from cloth pieces and that a protease concentration decrease from 1.0% to 0.5% (w/v) would not have a signi&64257;cant impact on percent blood removal if LAS concentrations between 1.5-2.0% (w/v) in combination with lower (<0.5%, w/v) concentrations of H2O2 were used. Thus, the protease from Bacillus licheniformis SMIA-2 can be effectively incorporated into cleaning formulations together with LAS and hydrogen peroxide to formulate more sustainable detergents.
Assuntos
Bacillus licheniformis , Detergentes/química , Peptídeo Hidrolases , Peróxido de HidrogênioRESUMO
BACKGROUND: Lipases are extensively exploited in lots of industrial fields; cold-adapted lipases with alkali-resistance are especially desired in detergent industry. Penicillium cyclopium lipase I (PCL) might be suitable for applications of detergent industry due to its high catalytic efficiency at low temperature and relatively good alkali stability. In this study, to better meet the requirements, the alkali stability of PCL was further improved via directed evolution with error-prone PCR. RESULTS: The mutant PCL (N157F) with an improved alkali stability was selected based on a high-throughput activity assay. After incubating at pH 11.0 for 120 min, N157F retained 70% of its initial activity, which was 23% higher than that of wild type PCL. Combined with the three-dimensional structure analysis, N157F exhibited an improved alkali stability under the high pH condition due to the interactions of hydrophilicity and ß-strand propensity. Conclusions: This work provided the theoretical foundation and preliminary data for improving alkali stability of PCL to meet the industrial requirements, which is also beneficial to improving alkali-tolerance ability of other industrial enzymes via molecular modification.
Assuntos
Penicillium/enzimologia , Estabilidade Enzimática , Indústria de Detergentes , Lipase/metabolismo , Penicillium/isolamento & purificação , Penicillium/genética , Reação em Cadeia da Polimerase/métodos , Temperatura Baixa , Álcalis , Biocatálise , Interações Hidrofóbicas e Hidrofílicas , Concentração de Íons de Hidrogênio , Lipase/isolamento & purificação , Lipase/genética , MutaçãoRESUMO
OBJECTIVE To study the influence of enzyme detergent for improving the quality during the cleaning of medical instruments.METHODS The 360 pieces of contaminated instruments for manually cleaning were divided into two groups with 180 pieces each, one group as test one immersed in Lionser enzyme solution 5 minutes at 1∶200 and another one as control immersed in non-enzymatic detergent 30 minutes at 1∶200.Eventually flush all instruments using free water.RESULTS Significant difference(P