Bacteria in Wooden Box Fermentation of Cocoa in Daklak, Vietnam

There are five main groups of microorganisms that participate in fermenting cocoa: filamentous fungi, yeasts, lactic acid bacteria, acetic acid bacteria, and various Bacillus species [1]. Fungi, yeasts, lactic acid bacteria, and acetic acid bacteria are active mainly in the first stage (from 0 to 48h). Yeasts convert sugar from the mucilage of cocoa beans into alcohol, and break the pectin down into pectinic acid, which enhances the quality of the cocoa beans [2]. Acetobacter pasteuriansis, a spontaneous bacterial species, plays a significant role in the cocoa bean fermentation process by oxidizing ethanol into acetic acid. They are capable of tolerating high ethanol levels and high temperatures, and thrive in the presence of calcium lactate and mannitol [3]. There is a high density of acetic acid bacteria (A. syzygii, A. pasteurianus and A. tropicalis) present during the fermentation process [4]. After stage 1 (from 48h to 72h), Bacillus species form, which kill the germ and break the tissue wall, and this allows for many reactions resulting in the formation of chocolate flavors and color of the cocoa bean. The current study employs molecular biotechnology to isolate and identify the bacterial species that ferment the cocoa bean in the Daklak province. This knowledge has, in turn, allowed the researchers to further explore the facts involving the fermentation process and the production of high quality cocoa beans in Vietnam.