Mabel Santander1, Alejandro Villegas1, Maria Isabel Gutierrez2, Ana Maria Castaño2 and Natalia Campillo-Pedroza2
1Ingenio Providencia, km 12 via Palmira – El Cerrito, Colombia; mcsantander@providenciaco.com
2BioDx Diagnostico y Soluciones Biotecnológicas S.A.S, Cl. 18 #122-135, Cali, Colombia; contactobiodx@gmail.com
The presence of contaminating microorganisms in ethanol production processes generates negative impacts on efficiency, making it essential to identify the microbial species present, their relevance, and their locations to establish optimal control strategies. This study was conducted to gain a thorough understanding of the composition of microbial communities present in raw materials and musts from alcoholic fermentation using sugarcane molasses and thus to propose improvements to the process. The samples were taken from different points in the ethanol production process: feed mix (B molasses and water), pre-fermenter, fermenters, yeast cream, acidified cream, and vinasse. A phylogenetic analysis using metabarcoding (targeted sequencing of taxonomically informative genetic markers (16S rRNA gene, ITS region, and nifH gene) was used to study the population dynamics of bacteria and fungi throughout the process. From the taxonomic analysis of the 16S rRNA gene sequences, 212 families of bacteria were identified, grouped into 518 genera, of which Lactobacillus spp. and Acetobacter spp.represent 80% of the sequences. A total of 38 genera of fungi and 40 species were identified throughout the ethanol production process, with evidence showing that 99.5% of the sequences belonged to the genus Saccharomyces, specifically Saccharomyces cerevisiae, with 17 variants of S. cerevisiae found. The feed mix and the propagator tank were the sampling points that exhibited the highest microbial load with the greatest diversity, meaning no dominant species was evident; the sampling points with the highest richness were the yeast cream and the acidifying tank. At the sampling points with high diversity, controls were established that affected most of the populations found; for the points of high richness, controls were directed towards the dominant population (specific antibiotics for Lactobacillus spp.). These results allowed for the implementation of strategies to control microbial contamination in the ethanol fermentation process.