Optimization corn processing wastewater-based medium and conditions for recombinant lipase production by Pichia pastoris yeast

In this study, Corn Processing Wastewater (CPW) is used to develop a cost-effective medium for production of recombinant Geotrichum sp. lipase by P. pastoris yeast, instead of expensive BMMY and high salt mineral mediums. The design of varying one variable at a time was used to determinate optimum additive components based on CPW for lipase production and yeast extract, peptone and MgSO4 were identified. After screening of significant variables by Plackett-Burman design and determination of the center points for Response Surface Methodology (RSM) by the path of steepest ascent design, yeast extract and initial pH were further optimized by RSM. An overall 4.94-fold increase in lipase production was achieved after medium and condition optimization following a series of approaches. CPW supplemented with suitable nitrogen source and salt as a fermentation medium for the yeast production of lipase is effective in shake flasks. This study demonstrated that renewable resource corn processing wastewater was a potential cost-effective fermentation medium for lipase production by yeast.