Lactiplantibacillus from Peruvian Criollo Blanco Cocoa and Cadmium Removal via a Bacterial Consortium During Cocoa Fermentation.

Abstract

Peru is the eighth largest producer of cocoa beans worldwide; however, the high cadmium content (Cd) presented in the white Criollo cocoa beans from the Piura region, has limited their commercialization. A potential strategy to mitigate this problem is the application of native lactic acid bacteria (LAB), capable of reducing Cd during the fermentation stage of the grain. Three Theobroma cacao L. fruits of the Creole variety were purchased from six farmers located in Malingas, district of Tambogrande, Piura, Perú. LAB were isolated, and their biosecurity and technological properties were assessed for potential use in the fermentation of cocoa beans derived from two phylogenetically characterized consortia 16S rDNA M1 (Lactiplantibacillus sp. COE1, L. plantarum COE4 and Lactiplantibacillus sp. COB2) and M2 (Lactiplantibacillus sp. COE1, L. plantarum L. plantarum COE4 and Lactiplantibacillus sp. CCC5). The concentration of cadmium was subsequently assessed. Twenty-four strains were isolated; however, seven were discarded because they were Gram-negative and presented positive hemolysis. Of the 17 LAB, 41% of the bacteria presented strong inhibition on Listeria monocytogenes, Salmonella enterica sv typhimurium, Escherichia coli ATCC10536, E. coli O157:H7 and Candida albicans. COE1 and COE2 presented high acidifying activity, COE3 high proteolytic activity, CCC4 high lipolytic activity, COE3 and COE5 high diacetyl synthesis, COB2, CCC5, COE1 and COE4 presented high resistance to cadmium (50 mg/L). Four strains were identified, two of which belonged to the genus Lactiplantibacillus (CCC5 and COE1) and two to the species L. plantarum (COE4 and COB2). M2 reduced the Cd content in dry cocoa beans with 8.5% moisture content by 3.89%.