A preliminary assessment of phenol tolerance and degradation by spent mycelium substrate (SMS) of novel edible mushroom <i style="mso-bidi-font-style:normal">Hypsizygus ulmarius</i>

Abstract

In assessing phenol tolerance and degradation using SMS of <i style="mso-bidi-font-style:normal">Hypsizygus ulmarius</i>, growth media using amylose gave mycelial growth of 16.28 sq cm at 200 mg/L phenol; this was reduced to 11.22 sq cm and further to 10.62 sq cm when phenol was increased to 400 and 800 mg/L. There was growth reduction of 13.26% and 1.57% from 200 to 800 mg/L phenol. Tolerance to lower phenol concentrations was better (5 sq.cm) in non-ligninolytic (Nx10 Cx10) media, while ligninolytic (N/10 C/10) condition provided better tolerance (3.38 sq.cm) at higher concentrations. Excessive reduction or increase of nutrients increased growth (N/10 C/10 – 11.29 sq cm; Nx10 Cx10 - 9.07 sq cm). When cellulose was used, growth of 22.46 sq cm at 200 mg/L phenol got reduced to 16.96 sq cm at 400 mg/L, and negligible decrease thereafter. Growth reduced by 9.77% from 200 to 800 mg/L phenol. All variations of ligninolytic (N/2 C/2; N/10; N/2; C/2) media offered good tolerance (7.18 sq cm). There was 47.1% phenol degradation in ligninolytic media (N/10 C/10; N/2; N/10) using amylose, while it was only 21.3% in non-ligninolytic condition (Nx10 Cx10). Degradation decreased by 3.7% and 1.46% when phenol increased to 400 and 800 mg/L. Ligninolytic cellulose (N/2 C/2; N/2; N/10) media gave 67.05% degradation, while it was only 35.4% in non-ligninolytic condition (Nx10; Nx2 Cx2). There was 9% decrease in degradation when phenol increased to 400mg/L and negligible thereafter. Overall, there was reduction in tolerance and degradation when phenol was increased from 200 to 400 mg/L; it was negligible beyond 400mg/L. Ligninolytic media was suitable for enhanced tolerance and degradation; the maximum potential achieved when nitrogen was reduced to one-tenth of optimum level. Cellulose was the preferred carbon source for tolerance; while better degradation was achieved in amylose. There was high similarity of growth pattern in non-ligninolytic conditions of the two carbon sources, indicated by correlation value of 0.78.