Investigation on Potential Starter of Bacillus spp. for Ivorian Cocoa Beans Fermentation Improvement

Abstract

To investigate some interesting functional properties of Bacillus spp. in cocoa fermentation processing, 702 strains of Bacillus sp. strains were isolated from six main Ivorian cocoa producer regions. Three mains technological and useful properties for good cocoa beans fermentation were monitored. Among the 386 pectinolytic Bacillus spp. strains, 86.79% of them were confirmed for enzymes production in liquid medium. These 335 pectinolytic Bacillus strains displayed variety of pectinolytic activity with 50.45% of them producing both pectinase and polygalacturonase (PG) enzymes. Among these 169 strains, 70% displayed both the ability to acidify the medium and to degrade the citrate. In mimic conditions of pH and temperature variations as for fermentation heap, 11 strains were able to maintain their activity ranged within 2.12 ± 0.02 to 0.41 ± 0.03 µmol/min/mg of proteins for PG and 2.36 ± 0.03 to 0.25 ± 0.03 µmol/min/mg of proteins for pectinase. Two species (T10T2 and T6HS10) identified as Bacillus subtilus and Bacillus thuringiensis, were selected as the best based on pectinase production level. They were able to continuously produce both pectinolytic enzymes in different conditions of organic acids and ethanol contents. The highlighted properties in this study and the performance of these two strains may make them best candidate as starters for cocoa fermentation control.