Application of Residual Yeast as a Source of Redox Mediators for the Anaerobic Decolorization of a Model Azo Dye

Abstract

-This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in batch reactors using discharged residual yeast as the source of redox mediators (RM). Two yeast lysis methods (mechanical lysis and sonication) were tested and optimized to produce a riboflavin-rich yeast lysate. The reactors were operated at 25 o C for 48 hours, evaluating the effect of external carbon source (glucose) and RM (from residual yeast lysate and commercial yeast extract) addition. The results showed that color removal efficiencies for the batch reactors fed with commercial yeast extract reached 90%, whereas those fed with discharged yeast lysate reached 80% (sonication) and 73% (mechanical lysis). These values were statistically higher when compared to reactors operating without RM (48 to 66%), demonstrating that yeast extract enhances azo dye degradation in anaerobic conditions and that the residual yeast is a cheap and alternative source of carbon and of the RM riboflavin.

Metabolization of by-products formed by ozonation of the azo dye Reactive Red 239 in moving-bed biofilm reactors in series

“…In aerobic biological processes, microorganisms require a long adaptation period for degradation of a simple azo dye, whereas in anaerobic processes azo dye degradation is easily accomplished (Firmino et al 2011;Baêta et al 2016;Victral et al 2016). However, the breakdown of the azo bond in anaerobic processes generally forms toxic products such as aromatic amines (Chengalroyen and Dabbs 2013).…”

Changes in Bacterial Community Structure in Wastewaters in the presence of Saccharomyces Cerevisiae and Benzalkonium Chloride

“…Yeast biomass contains proteins, ribonucleic acid, lipids, ash and fibre in concentrations up to 49, 6, 3, 9 and 24%, respectively [5]. Due to the high nutritional value of yeast, it is often used as an animal feed [2,6].…”

Co-digestão anaeróbia de efluente têxtil com levedura residual oriunda do processo de fermentação alcoólica visando remoção de cor e produção de biogás

“…Um outro ponto a ser analisado é que, em condições aeróbias, o oxigênio é aceptor preferencial de elétrons quando comparados aos corantes azo devido a presença de grupos funcionais eletrofíticos em sua estrutura. Dessa forma, os corantes não são reduzidos preferencialmente, tornando-os mais resilientes a processos aeróbios de degradação (VICTRAL et al, 2016).…”