<span style="font-size:15.0pt;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Evaluation of Upstream Process parameters influencing the growth associated PHA accumulation in <i style="mso-bidi-font-style:normal">Bacillus</i> sp. Ti3</span>

Abstract

Batch fermentation of a newly characterized <i style="mso-bidi-font-style:normal">Bacillus</i> strain, <i style="mso-bidi-font-style:normal">Bacillus</i> sp. Ti3, was investigated for PHA accumulation. Time course study revealed growth associated PHA production, with maximum PHA yield 0.6 ± 0.02 g/L and 44.1 ± 0.9 % PHA accumulation coinciding with the maximum biomass stage of 24 h followed by a time dependent decline due to onset of sporulation. pH 7 supported maximum PHA yield of 0.86 ± 0.01g/L and PHA accumulation of 48.0 ± 0.72 %. Biomass of 2.1 ± 0.1 g/L and 0.92 ± 0.07 g/L PHA yield was obtained with 4% (v/v) inoculum. Glucose supplemented with casein hydrolysate gave the highest biomass 1.85 ± 0.02 g/L, PHA yield 0.96 ± 0.02 g/L and 51.6 ± 0.5 % PHA accumulation. Fermentation kinetic parameters of the <i style="mso-bidi-font-style:normal">Bacillus</i> sp. Ti3 grown in batch cultures with optimized culture conditions accounted for 1.7 and 1.2 fold increase in PHA yield (0.57g/L to 0.96g/L) and PHA accumulation (44.1% to 51.6%). FTIR analysis of the polymer revealed that the strain was a potent polyhydroxybutyrate (PHB) producer. A relatively high yield of polyhydroxybutyrate within 24h, independent of nutrient limitation and precursors in a single growth phase makes this strain a promising option for industrial PHA production.