Selection of vinasse-degrading microorganisms

DEL GOBBO LUCIANA MELISA; RULLI MACARENA MARIA; CUOZZO SERGIO ANTONIO; COLIN VERONICA LETICIA

Congreso; XII Congreso Argentino de Microbiologia General; 2017

One of the main problems of the sugar-alcohol industries is the generation of large volumes ofvinasse. The release of this acid effluent generated during the alcoholic distillation causes anundesirable environmental impact as a consequence of the high content of organic matter and othertoxins. Many technologies based on vinasse conditioning by microbial pathways are continuouslyevaluated in order to mitigate their environmental impact. In the current study, a preliminary selectionof microorganisms from the soil with the potential to grow and degrade effectively the sugarcanevinasse was performed. To perform the isolation, two vinasse concentrations in distilled water (10 and30%, v/v) added with 2% agar (w/v) were used as selective solid media (VS10 and VS30). Anaqueous suspension obtained from a sugarcane vinasse-contaminated soil was inoculated in the VSmedia. A suspension obtained from same soil but without vinasse was also inoculated in these mediato be used as controls. After 48 h of incubation at 30ºC, spores of the microorganisms developed inthe VS media were harvested and quantified to be inoculated in a liquid medium consisting of 30%vinasse in distilled water (VL30). At the 72 h of incubation in VL30 (at 30ºC, 150 rpm), the biomassconcentration was measured by estimation of the dry weight at 80°C, while the biological oxygendemand in 5 days was quantified by a standard method (BOD5). Under the current assay conditions,no microbial growth in the VS media from the soil samples without vinasse can be detected. However,two types of colonies from soil exposed to raw vinasse were isolated using VS30 as a selectivemedium. Microscopical observations of the two isolates denoted as V1 (spores pink) and V2 (greenspores), revealed sparsely branched and septate hyphae as well as the presence of aspergillaryheads. Both isolates were able to grow in VL30 and remove over 50% of the biodegradable organicmatter, suggesting a proportional reduction in the effluent toxicity. This finding could be promising interms of the future application of both strains for recovery of effluents with high load organic likevinasse. Supported by PICT 2015 Nº 0297 and CONICET.