Optimization of dextran production by Weissella cibaria NITCSK4 using Response Surface Methodology-Genetic Algorithm based technology

Abstract

The most influencing factor on dextran production by Weissella cibaria NITCSK4 were screened using Plackett Burman design at 95% confidence limit with higher value of co-efficient of determination (R²) 99.58%. The combined effects of significant factors, namely, sucrose, temperature, dipotassium hydrogen phosphate (K₂HPO₄) and yeast extract were studied and optimized using Response Surface Methodology (RSM). The input parameters of non-linear models predicted by RSM were subsequently optimized using the genetic algorithm (GA) for obtaining a maximum dextran yield. The maximum yield was obtained with sucrose concentration of 15.78%, yeast extract 1.27%, K₂HPO₄ 1.25%, and at 26°C. The predicted conditions were experimentally validated and 43.79mg/ml of dextran was produced. The dextran yield was 51% higher as compared to unoptimized medium. The molecular weight of resulting dextran produced at 26°C is >2000kDa. The NMR spectroscopic analysis demonstrated that the NITCSK4 produced linear dextran with predominant α (1-6) linkage.

Keywords: Dextran; Plackett burman design; Response surface methodology and genetic algorithm.; Weissella cibaria NITCSK4.