Ethanol and organic acid production related to the microbial population in sugarcane silages with admixed crambe (Crambe abyssinica Hochst) bran

Abstract

ABSTRACT The dry matter contents (DM), growth of colonies of lactic acid bacteria (LAB), enterobacteria (ENTERO), yeast fungi (YF), and filamentous fungi (FF), acidity values (pH), organic acid and ethanol production (ET), were evaluated for sugarcane silages with different ratios (LI) of admixed crambe bran (CB). The ratios were 0, 3, 10, 17 and 20% of the total silage mass, which were evaluated at different storage times (ST) (0, 3, 7, 12, 24, 36, 41 and 60 days after the ensilage). The results were statistically analyzed using response surface methodology. The DM contents were influenced by increasing CB levels in the mixture, as it increases the moisture absorption and provides a favourable environment for LAB development, to the detriment of harmful microorganisms in the sugarcane-crambe mixture. The CB controlled the growth of YF, reducing ET by over 50%. The use of CB in proportions of up to 20% is a viable alternative for improving the fermentation profile of sugarcane silages, provided that they are stored for at least 60 days. Moreover, the use of the CB improves the sustainability of the industrial production of biofuels from the environmental points of view. Abbreviation list CB: crambe bran; ST: storage time; LI: levels of inclusion; CV: coefficient of variation; GE: general equation; CFU: colony forming units; DM: dry matter; pH: potential hydrogen; LA: lactic acid; AA: acetic acid; BA: butyric acid; ET: ethanol production; LAB: lactic acid bacteria; ENTERO: enterobacteria; YF: yeast fungi; FF: filamentous fungi