Efficient Production of Exopolysaccharide by Submerged Fermentation of Hypsizygus marmoreus Using a Two-stage pH Control Strategy

Abstract

The effects of culture conditions and pH values on the exopolysaccharides (EPS) production by Hypsizygus marmoreus were investigated in this work. The results showed that the optimal carbon and nitrogen sources were glucose and yeast extract at concentrations of 30 g L -1 and 12.5 g L -1, respectively. In constant pH fermentation, high biomass concentration and the specific cell growth rate were achieved at pH 6.5, while high EPS concentration and the specific EPS production rate were obtained at pH 7.5, respectively. Based on kinetics analysis, a two-stage pH strategy was proposed in which pH was controlled at 6.5 to maintain high cell growth and glucose consumption in the first 48 h, and then shifted to 7.5 for increasing EPS production. The maximal EPS concentration reached 2.31 ± 0.07 g L -1 by applying this strategy. The EPS productivity (0.024 g L -1 h -1 ) increased 58.94 %, 172.7 % and 35.73 %, respectively, compared with that of the natural pH, and controlling pH at 6.5 and 7.5.

Optimization and Rheological Study of an Exopolysaccharide Obtained from Fermented Mature Coconut Water with Lipomyces starkeyi

“…As is well-known, carbon and its concentration usually play an important role because the nutrient is directly involved in cell proliferation and metabolite biosynthesis [ 30 ]. The yield of crude LSEP improved with the increase in glucose concentration, which may because the glucose provided enough carbon source for the L. starkeyi , resulting in the increase in cell number and then increasing the yield of LSEP.…”

“…It may because excessive quantities of Zn 2+ and Mn 2+ were toxic, resulting in decreased growth or increased death [ 31 ]. The pH of the medium can also affect cell growth and the production of metabolites, which may be because pH can affect the permeability of the cell membrane and the activity of some enzymes [ 30 ].…”

Data_Sheet_1.xlsx

“…Hypsizygus marmoreus is one of the most popular industrialized cultivation mushrooms in East Asia, including China, Korea and Japan (Qiu et al, 2013;Chauhan et al, 2017;He et al, 2019;Wu et al, 2019). It draws our attention due to its desirable, mildly sweet nutty flavor, unique texture and medicinal properties (Chen et al, 2018;Liu et al, 2018a;Shah et al, 2018). As a result, the number of H. marmoreus cultivation factories increased gradually in different regions of the world, especially in China.…”