Optimization of medium composition for soluble dietary fibre production by Ganoderma lucidum using lotus root pomace

Abstract

Statistical experimental designs were applied for the optimization of medium constituents for soluble dietary fiber (SDF) production by Ganoderma lucidum in solid state fermentation (SSF) using lotus root pomace (LRP) as the substrate. Factors including wheat bran, MgSO4, FeSO4 and VB1 were identified by Plackett-Burman design (PBD) as significant for SDF production. The path of steepest ascent design (SAD) was undertaken to determine the optimal region of four significant factors. To determine the optimal values of the significant variables, Box-Behnken design (BBD) and response surface analysis were employed. The optimum conditions were found to be the 5g LRP, 1.77 g wheat bran, 0.029 g/L MgSO4, 0.011 g/L FeSO4 and 0.052 g/L VB1. SDF production at these optimum conditions was 0.113 g/g DW substrate. Compositional analysis showed that SDF was composed of rhamnose, xylose, mannose, galactose and glucose in a molar ratio of 1.2:1.0:1.6:7.2:56.9.