Study on the biodegradation of phenol derivatives by oleaginous yeast Rhodosporidium toruloides 9564T and effect of heavy metals on phenol degradation

Abstract

An increase in industrialization has led to the indiscriminate discharge of concentrated harmful chemical pollutants into the environment, which directly impacts the nature. Heavy metals and phenol derivatives are present in industrial effluent, making their remediation challenging. The use of oleaginous yeast Rhodosporidium toruloides 9564T in the treatment of wastewater containing phenol and its derivative is a research focus. The oleaginous yeast can resist heavy metals and degrade phenol and its derivative effectively. Experiments were designed using simulated wastewater by varying 4-chlorophenol and catechol concentration in the range of 0.25 – 1.5 g/L with an inoculum size of 10%. The oleaginous yeast R. toruloides 9564T was found to completely degrade 4-chlorophenol upto 0.75 g/L and catechol upto 1 g/L. The effect of heavy metal chromium (Cr) in the range of 5-25 mg/L on phenol degradation was also studied using the yeast, and the obtained result confirmed that above 5 mg/L of chromium had a significant impact on phenol degradation by extending the degradation period from 36 h to 108 h in 0.5 g/L phenol concentration. The maximum biomass and lipid content obtained from 4-chlorophenol and catechol degradation were 2.38 g/L and 4.03 g/L, and lipid content was 28.37 and 34.6% respectively. After complete degradation of phenol derivatives, the samples were used for the toxicological study. Therefore, the use of oleaginous yeast R. toruloides 9564T for treatment of phenolic wastewater and lipid production could be an economical approach towards biodiesel production.