Advances in microbial contamination in the production of fuel bioethanol: Origin, problems, and control methods

Biofuels are important sustainable fuels and bioethanol stands out in the countries with biomass resources. However, the fuel ethanol fermentation is not aseptic and the recycling of yeast cells stimulates the increase of bacterial contamination. Lactic acid bacteria are the most important group in this industry, especially Lactobacillus fermentum. The contaminants decrease the industrial ethanol yield and inhibit the yeast metabolism, beyond the increase of the cost and lead to operational problems. Then, some technological methods are employed for bacterial control. In this chapter, these methods have been discussed with their limitations. Furthermore, new alternatives are presented.