RESUMO
This paper reports on the optimization of poly(gamma-glutamic acid) (PGA) production by Bacillus licheniformis NCIM 2324 using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources, nitrogen sources and pH on PGA production. Plackett-Burman design was adopted to select the most important nutrients influencing the yield of PGA. After identifying effective nutrients, response surface methodology was used to develop a mathematical model to identify the optimum concentrations of the key nutrients for higher PGA production, and confirm its validity experimentally. PGA production increased significantly from 5.27 to 26.12 g/l when the strain was cultivated in the optimal medium developed by using statistical approach, as compared to basal medium.
Assuntos
Bacillus/metabolismo , Reatores Biológicos/microbiologia , Carbono/metabolismo , Técnicas de Química Combinatória/métodos , Modelos Biológicos , Nitrogênio/metabolismo , Ácido Poliglutâmico/análogos & derivados , Simulação por Computador , Interpretação Estatística de Dados , Fermentação , Concentração de Íons de Hidrogênio , Ácido Poliglutâmico/metabolismo , Controle de Qualidade , VaporRESUMO
This work reports on the optimization of PGA production by Bacillus licheniformis NCIM 2324 in solid state fermentation (SSF). In the first step, the one factor-at-a-time method was used to investigate the effect of solid substrates, initial moisture content, pH, and additional carbon and nitrogen source on PGA production; subsequently, response surface methodology (RSM) was used to establish the optimum concentrations of the key nutrients for higher PGA production. In the second step, the effects of amino acids and TCA cycle intermediates on the production of PGA were studied. The final optimized medium gave a maximum yield of 98.64 +/- 1.61 mg gds(-1) of PGA, which is significantly higher than that reported in the literature.
