Valorization of the Mucilage Juice of Cocoa Beans for the Production of a Biopesticide based on Bacillus thuringiensis var.kurstaki HD-1

Abstract

The use of microbial pesticides in agriculture has someadvantages, but their production ina non-conventional experimental tests constituate a challenge. This study purpose is to evaluate the potential of cocoa mucilage juice. The mucilage juice of cocoais a substratum, that has been used as an alternative growing test and associated to bacteria such as Bacillus thuringiensis var. kurstaki HD-1 (Btk HD-1) for the production of a biopesticide. After determining the physico-chemical characteristics of the mucilage juice, different combinations has been made with 2% (M2%), 4% (M4%), 6% (M6%) and 7% (M7%) cane molasses were established, then inoculated with 2% of the inocula and incubated at 30 °C for 48 hours under agitation. The results showed that the substratum contained nitrogen (1.68g/L) and carbon (9.9 g/L), which has an important mineral such as potassium (87.3 mg/L), phosphorus (38 mg/L) and magnesium (25.42 mg/L). The growth of Btk HD-1 in cocoa mucilage juice with 2% molasses (M2%) was the highest (p < 0.0001) with average concentration of 1.6×10 9 CFU/mL for cells and 2.3×10 9 CFU/mL for spores. This combination therefore offers good prospects for the production of the Btk HD-1 biopesticide.