Optimization of culture conditions of iron - enriched biomass of saccharomyces pastorianus by respone surface methodology

Abstract

A profound and safer treatment and preventation from anaemia development is yeast biomass enriched with iron. Effect of culture conditions (temperature, degrees brix, time and initial iron concentration) on the bioaccumulation of ferric ion (Fe3+) in yeast (Saccharomyces pastorianus) were investigated by response surface methodology (RSM) in this study. The combined effects of culture conditions on Fe yield were studied using a three level four-factor Box–Behnken design. Fermentation was carried out at different temperature (20–32oC), degrees brix (12 – 16oBx), time (24 – 72h) and initial iron concentration (500 – 1000ppm). The results showed that the optimum conditions for Se enrichment of yeast were found at temperature of 24oC, degrees brix of 13oBx, time of 49h and initial iron concentration of 656 ppm. Total Fe3+ yield was significantly affected by culture temperature and degrees brix (P < 0.0001). Under optimum conditions, the maximum level of Fe (III) ions in dry cell weight of S. pastorianus was 16.825 ± 0.651 mg/g. Based on analysis of variance (ANOVA), the model was acceptable (P < 0.0001), adequate and reproducible due to significant both R – squared and adjusted R – squared (R2 = 0.935) and insignificant lack of fit. Key word: Saccharomyces Pastorianus, Fe (III) citrate, response surface methodology, optimization, Box – Behnken.