Potential biotreatment of wastewater from tannery industry

MARIANA DEL PÓPOLO GRZONA; BIBIANA BARBERO; ALEJANDRO A. ORDEN

Encuentro; 1st CYTED Iberoamerican meeting about water treatment from AMARU; 2021

Universidad Católica de Santa María

The tannery industry generates wastewater with high concentrations ofpollutants such as tannins and chromium. The aim of this work was tostudy the ability of microorganisms to tolerate the presence of Cr(VI) andtheir potential to degrade tannic acid (TA). From fungal growth in aconcentrated solution of TA, 3 g L-1, isolations were made ondifferent culture media (PDA, MEA and CYA) choosing CYA for further studies.Microscopic observations indicated that all isolated fungi belong to the genus Penicillium. From conidial suspensions,the minimum inhibitory concentration (MIC) of Cr(VI) was analyzed against 6 ofthe fungi and indicated that all of them tolerated up to 100 ppm. One of thefungi was chosen for TA biotransformation assays at 1, 3 and 5 g L-1.First, the fungus was pre-cultured on Czapek for 2 days, under agitation at 28°C and in darkness, until pellet formation. On one hand, the fungus wasinoculated by direct spiking and then, in order to optimize the methodology, asuspension of conidia was inoculated (final concentration: 2.5x105CFU/mL). Then, the medium was replaced with the TA solutions. The assays wereperformed in triplicate for 7 days, under the described conditions. Monitoringwas done by UV-Vis spectrophotometry and chemical oxygen demand (COD). The testwith direct inoculation resulted in 100% degradation of TA, 74% reduction ofCOD for 1 g L-1 of TA and 89% for 3 g L-1 of TA. The testfrom conidia suspension resulted in 63% reduction in COD for 3 g L-1of TA and 80% for 5 g L-1 of TA. In conclusion, the fungus studiedshows potential for application in the biotreatment of tannery wastewater