Polygalacturonase production enhancement by Piriformospora indica from sugar beet pulp under submerged fermentation using surface methodology

Abstract This study proposed a novel and cost-effective approach to enhance and optimize the polygalacturonase from P. indica. In current investigation, the impact of ammonium sulfate, sugar beet pulp (SBP) and glucose as variables on induction of polygalacturonase from P. indica was optimized using the central composite design (CCD) of response surface methodology (RSM) under submerged fermentation (SmF). Additionally, partial polygalacturonase purification and in situ analysis were performed. The optimal reaction conditions, which resulted in the highest enzyme activity were observed as the following conditions: ammonium sulfate (4 g/L), SBP (20 g/L), glucose (60 g/L). Under the optimized condition, the maximum enzyme activity reached to 19.4 U/ml (127 U/mg) which increased by 5.84 times compared to non-optimized conditions. The partial purified polygalacturonase molecular weight was estimated 60 KDa. In line with the bioinformatic analysis, exo-polygalacturonase sequence of P. indica showed similarity with Rhizoctonia solani’s and Thanateporus cucumeris. These results indicated that SBP act as a cheap and suitable inducer of polygalacturonase production by P. indica in a submerged cultivation. The outcome of this study will be useful for industries to decrease environmental pollution with cost-effective approaches.