Remediation of sugarcane vinasse using Rhodotorula glutinis or Rhodotorula mucilaginosa: biomass morphology and its potential technological applications

JUAN MANUEL ALFARO; SARITA REYES; HECTOR ANTONIO CRISTÓBAL; MARIA RITA MARTEARENA; MARIO DOMINGO BAIGORI; LICIA MARIA PERA

Biocatalysis and Agricultural Biotechnology

ScienceDirect

Año: 2023

1878-8181

There is an emerging interest of use biological processes for vinasse treatmentgenerally because they are able to produce interesting metabolites from living cells.Additionally, the production of yeasts with weakened cell wall without modifying itsphysiological performance would be of great technological value not only to facilitatethe extraction of intracellular metabolites but also to increase the biomass digestibility.This study explored the remediation of a glycerol-fortified sugarcane vinasse usingRhodotorula glutinis or Rhodotorula mucilaginosa coupled with the production ofvaluable residual biomasses displaying a tailor-made weakened cell wall. Firstly, thebiomass-bound ß-D-glucosidase activity was selected as a proper cell wall lyticpotential marker. Secondly, in vitro-dose response assays with several metal ionsshowed that the presence of 6 mM of MnCl2 and FeCl3 increased the ß-D-glucosidaseactivity in R. glutinis and R. mucilaginosa, respectively. Thirdly, the supplementation ofthose salts to either YPD or vinasse-based media was evaluated. As a result, cellswere bigger or even rounder than the corresponding controls (without metal ionssupplementation) suggesting a weakening of the cell wall. Finally, as proof of concept,after 6 days of treatment at 30 °C under stirred conditions, the reduction of COD valuefor R. glutinis and R. mucilaginosa was 81.3% and 80.8%, respectively. The finalbiomass, lipid and protein concentrations for R. glutinis were 15.1 g/L, 31.1% and48.12%, respectively. The final biomass, lipid and protein concentrations for R.mucilaginosa were 15.7 g/L, 31.5% and 48.12%, respectively. Besides, potentialtechnological applications of residual biomass were also discussed.