Lipases are enzymes that catalyze the hydrolysis of the ester linkage in a triacylglycerol oil-water interface, while in non-aqueous environments they catalyze reverse reactions (esterification, transesterification and interesterification). They can be produced by a solid state fermentation (SSF) process adding value to agro-industrial residues as alkaline soapstocks that can be used as a lipid substrate for lipase production. The objective of this study was to characterize the soapstocks of canola, sunflower and corn and use these byproducts for fungal lipase production using the mutant strain 11T53A14 of Aspergillus niger. The work was carried out following 2 4-1 and 2 3 experimental designs in the presence and absence of inducers, respectively, aiming to evaluate the influence of some variables in the lipase production. The production by SSF was carried out in aerated columns incubated at 32°C. Among the soapstocks evaluated, the sunflower soapstock was the best inducer for enzyme production, with 201 U/g dm (gram of dry medium) using 10 8 spores/g m (gram of medium) inoculated on wheat bran humidified with 80 mL of liquid (ammonium sulfate solution) that corresponds to a final concentration of 0.5% nitrogen, and 3% inducer. The best lipase activity obtained without soapstock was 182 U/g dm under the same processing conditions as the experiment using soapstock. Although the results with the highest lipase activity with sunflower soapstock and without inducer are close, the Tukey test showed a significant difference of these results, which proves the importance of lipid substrate to improve the lipase activity.
Lipases have various industrial applications and their production by filamentous fungi in solid state fermentation (SSF) process is of interest. In this work the lipase enzyme production by the mutant Aspergillus niger 11T51A14, which is a well-known lipase producer was studied using wheat bran as substrate. Microorganism used in fermentation process was inoculated at a concentration of 10 7 spores/g m into the medium containing nitrogen (ammonium sulfate), sunflower soapstock and wheat bran. The SSF process for enzyme production was carried out in aerated columns immersed in a water bath at 32ºC for 72 h. The process was studied using a central composite rotatable design 2 2 , where variables tested were the nitrogen concentration (0.32-0.88 % w/w) and the volume of liquid (60.9-89.1 mL). The lipase activity was analyzed in enzymatic extracts. The wheat bran, in the fermentation medium, acted as a carbohydrate source and as an inducer for the lipase production. The maximum enzyme activity found was 153.4 U/g dm , with a nitrogen concentration of 0.6 % and 89.1 mL of volume of liquid. The response surface model demonstrated that higher volume of liquid had a positive effect in lipase activity, while nitrogen concentration showed an optimal range (0.4-0.6%).
Autores têm demonstrado deficiência na adoção de práticas higiênico-sanitárias durante a ordenha em propriedades leiteiras localizadas em diferentes regiões do Brasil, o que contribui para o aumento Contagem Padrão em Placas (CPP) e consequentemente, da inflamação da glândula mamária, a qual está relacionada ao aumento da Contagem de células somáticas (CCS). Nesse contexto, o Ministério da Agricultura, Pecuária e Abastecimento (MAPA) publicou em 26 de novembro de 2018, a Instrução Normativa 77, que preconiza a interrupção da coleta do leite cru refrigerado na propriedade que apresentar, por três meses consecutivos, resultados de média geométrica da CPP acima de 300.000 UFC/mL. Com exceção da comprovação, pelo produtor, do acompanhamento de técnico capacitado na propriedade e apresentação do resultado de análise de CPP dentro do padrão, emitido pelo laboratório da Rede Brasileira de Qualidade do Leite (RBQL) no mesmo mês referente à terceira média geométrica acima de 300.000 UFC/mL. Verificando-se as dificuldades enfrentadas pelos produtores rurais para o atendimento dos parâmetros de qualidade determinados na legislação brasileira e o impacto para a sua permanência da atividade leiteira, este trabalho teve como objetivo analisar a influência da implementação das Boas Práticas Agropecuárias (BPA) na CPP e na CCS. Observou-se que a adoção de práticas simples como, o desprezo dos três primeiros jatos de leite, pré-dipping e pós-dipping, secagem dos tetos com papel toalha, higienização dos utensílios usados na ordenha e a eliminação da água residual dos materiais, foram eficientes para redução da CPP e CCS. Contudo, para melhoria significante da CCS torna-se necessário a inserção de um programa de controle de mastite, envolvendo as boas práticas de ordenha e a realização de testes para detecção da mastite, o descarte de vacas com mastite crônica, o tratamento de animais doentes e a separação de vacas sadias daquelas acometidas.
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