Enhanced Production of Acyltransferase from Rhodococcus pyridinivorans using Statistical Experimental Design

Abstract

Optimization of growth parameters for enhanced production of acyltransferase by Rhodococcus pyridinivorans were carried out using one-variable-at-a-time strategy (OVAT) and statistical designs of response surface methodology (RSM) to describe the relationship between tested variables. Optimization resulted into 3.8 folds increase in the acyltransferase production (448.44 ± 7.00 Umg-1 dcw). Based on results of Plackett-Burman design, combined effect of variables viz. pH, temperature, inoculum size and nonsubstrate inducer acetonitrile on production of acyltransferase were investigated at four levels, through the statistical analysis of central composite design (CCD). The statistical optimization showed further increase in acyltransferase activity of 1.06 folds. The validation of the experiments was also done by point determination in generated model with actual and predicted response level under optimized condition which resulted acyltransferase production of 480.8 ± 2.01 U mg-1 dcw (Predicted response 474.71 U mg-1 dcw). After performing optimization of all production parameters, 4.2 fold increase in acyltransferase production (519.03 ± 1.093 U mg1 dcw) was recorded with 3.0 % (w/v) acetamide, 1.5 % (w/v) yeast extract, 0.5 % (w/v) NaCl, 0.2 % (w/v) glucose, pH 7.0 at 30°C, 8 % (v/v) inoculum size and acetonitrile in multistep feeding as non substrate inducer (70 mM) for 18 h.