Evaluation of Lactic Acid Production by Different Bacillus Subtilis Strains Isolated from Theobroma Cacao Crops in Ecuador

Abstract

Lactic acid (LA) is an organic compound with numerous applications in the chemical, pharmaceutical and food industries. In addition, the study of its production has garnered renewed interest due to its applicability in the generation of biopolymers, seeking to lower operating costs and cultivation conditions. Ecuador has a growing demand for LA, but it lacks local production, despite having a microbial diversity that can be used for this purpose. Among the microorganisms that stand out for their production potential is Bacillus subtilis. In the present project, 7 strains of Bacillus subtilis isolated from cocoa crops, a cultivar of great local importance, were studied. These were identified by sequencing the 16s ribosomal and API50 galleries. The strains which were tested for LA production from glucose. The 3 best strains for LA production were identified and their yields were evaluated under aerobic, anaerobic and microaerobic conditions. The highest production of LA was evidenced under aerobic conditions with efficiencies of approximately 0.25 grams of LA per gram of glucose in the three best strains, equivalent to 5 g / L LA. Through the present investigation, it was possible to establish methodologies and achieve reasonable LA production with Bacillus subtilis strains, in addition, 3 promising strains for the production of LA in the country were identified.