Role of <i>CcpA</i> in Polyhydroxybutyrate Biosynthesis in a Newly Isolated <i>Bacillus</i> sp. MA3.3

Abstract

The ccpA gene was inactivated in the polyhydroxybutyrate (PHB)-producing strain Bacillus sp. MA3.3 in order to reduce glucose catabolite repression over pentoses and develop improved bacterial strains for the production of PHB from lignocellulosic hydrolysates. Mutant Bacillus sp. MSL7 ΔCcpA are unable to grow on glucose and ammonia as sole carbon and nitrogen sources, respectively. Supplementation of glutamate as the nitrogen source or the substitution of the carbon source by xylose allowed the mutant to partially recover its growth performance. RT-PCR showed that CcpA stimulates the expression of the operon (gltAB),responsible for ammonia assimilation via glutamate in Bacillus sp. MA3.3. Moreover, it was demonstrated that the supplementation of xylose or glutamate was capable of stimulating gltAB operon expression independently of CcpA. In PHB production experiments in mineral media, it has been observed that the glucose catabolite repression over the pentoses was partially released in MSL7. Although the carbohydrate consumption is faster in the ccpA mutant, the biomass and PHB biosynthesis are lower, even with supplementation of glutamate. This is attributed to an increase of acetyl-CoA flux towards the tricarboxylic acid cycle observed in the mutant.

EliA is required for inducing the stearyl alcohol-mediated expression of secretory proteins and production of polyester in Ralstonia sp. NT80

“…(Tanadchangsaeng et al, 2009;Lopes et al, 2011;Raberg et al, 2011). This polymer is formed in the presence of excess supply of carbon and/or in the absence of one or more essential nutritional elements, and it can account for as much as 85 % of the cell dry weight under optimized growth conditions (Yamada et al, 2007;Jendrossek, 2009;Beeby et al, 2012).…”

Análise econômica da produção de polímeros biodegradáveis no contexto de uma biorefinaria a partir de cana-de-açúcar.

“…(Lopes et al, 2011). Foram obtidos recombinantes com a repressão catabólica parcialmente abolida, porém afetados no uso de compostos nitrogenados.…”

Caracterização de bactérias halotolerantes isoladas do bioma caatinga e avaliação da produção de biopolímeros.

“…Embora a porcentagem de acúmulo tenha sido maior em todos os isolados usando o meio mineral glicose, observou-se que o acúmulo em meio mineral xilose foi semelhante, por exemplo, o isolado sac66 acumulou 26,9 % em MMG e 21,4 % em MMX (Tabela 9). Porém, deve-se ressaltar que as porcentagens de acúmulo dos isolados produtores da caatinga podem ser melhoradas através de ferramentas de biologia molecular ou mudando os processos fermentativos (condições de fermentação) (DHANGDHARIYA et al, 2015;HUANG et al, 2016;KUMAR et al, 2013KUMAR et al, , 2014LOPES et al, 2011;SINGH et al, 2011;YUE et al, 2014;ZHANG et al, 2014). milhões de toneladas, dados UNICA).…”