Valorisation of Cassava Wastewater as Substrate for Trichoderma virens Production, Bio-control Agent Cocoa Black Pod Disease

Aim: In Côte d'Ivoire, several food products are made from cassava. However, this production generates effluents such as wastewater responsible for soil, as well as water and air pollution. Meanwhile, cassava wastewater can be used as an inexpensive substrate for the production of biopesticides, such as Trichoderma virens, a bio-control agent for black pod disease. This could address both the problems of cassava wastewater treatment and the use of conventional synthetic substrates for biopesticide production.

Methodology: The experiments described here were conducted using the cassava wastewater, without any supplement, to produce spores of T. virens by liquid state fermentation, solid state fermentation on kaolin grains. The production of gliovirin in cassava wastewater was monitored by LC / MS analysis.

Results: The maximum production (≈ 1.7 x 108 spores / mL) was achieved at dilution 1/4 of the cassava wastewater while at dilutions 1 and 1/2 the concentrations were 6.3 x 106 and 7.2 x 106 spores / mL, respectively. Spores concentration increased when cassava wastewater was highly diluted. The cultures of T. virens on kaolin supplemented with the cassava wastewater recorded a concentration of 1.13 x 106 spores / g of kaolin. The presence of gliovirin was detected by LC/MS analysis of solid state fermentation of T. virens in cassava wastewater.