Browsing by Author "Ramos, Nuno"
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- Evaluation of the resistance of Acetobacter aceti to the major chemicals found in winery wastewaterPublication . Ramos, Nuno; Fernandes, Annabel Dias Barrocas; Fernandes, Maria da ConceiçãoThe wine industry generates between 0.2 and 4 L of wastewater per liter of wine produced, although this figure can exceed 14 L, depending on several factors. Wine effluent typically has high salinity and organic load, containing various organic compounds such as carboxylic acids, sugars, alcohols, and phenolic compounds. These compounds can inhibit microbial growth, compromising biological treatment processes. Naturally present in all stages of winemaking, Acetobacter aceti has the ability to oxidize ethanol into acetic acid and use the acetate produced in its metabolism. The present study aimed to evaluate the tolerance of A. aceti to two concentrations (LC and HC) of mixtures of: A-alcohols (ethanol, glycerol, and methanol), CA-carboxylic acids (acetic, succinic, and tartaric) and phenolic-Ph compounds (tyrosol and catechol) present in basal media, and to investigate the possibility of its use in the biodegradation of this effluent, through bacterial growth evaluation, degradation of the different compounds and assessment of chemical oxygen demand (COD) and total organic carbon (TOC). In the presence of alcohols, the growth rate (µ) and biomass yield (Y ??/??) of A. aceti decreased to 80% and 77% and to 73% and 88%, compared to the control, for LC and HC, respectively. The mannitol consumption rate (QM) decreased by 59% and 44%, compared to the control, for LC and HC, respectively. COD and TOC did not show differences. In the presence of AC, µ and Y ??/?? of A. aceti decreased to 61% and 43% and to 84% and 13%, compared to the control, for LC and HC, respectively. QM was reduced by 98% and 93%, compared to the control, for CL and HC, respectively. COD and TOC did not show differences. A. aceti, was unable to metabolize the tartaric acid. The presence of Ph did not affect growth, QM, COD, or TOC. The tests with real winery wastewater showed that the growth of A. aceti suffered a great reduction, requiring much more time to adapt and consume organic acids, except for tartaric. COD and TOC removals were 62% and 70%, for conditions without and with supplementation, respectively.