Biodegradation of Chlorinated and Non-chlorinated VOCs from Pharmaceutical Industries

Abstract

Biodegradation studies were conducted for major organic solvents such as methanol, ethanol, isopropanol, acetone, acetonitrile, toluene, chloroform, and carbon tetrachloride commonly used in pharmaceutical industries. Various microbial isolates were enriched and screened for their biodegradation potential. An aerobic mixed culture that had been previously enriched for biodegradation of mixed pesticides was found to be the most effective. All the organic solvents except chloroform and carbon tetrachloride were consumed as primary substrates by this mixed culture. Biodegradation rates of methanol, ethanol, isopropanol, acetone, acetonitrile, and toluene were measured individually in batch systems. Haldane model was found to best fit the kinetics of biodegradation. Biokinetic parameters estimated from single-substrate experiments were utilized to simulate the kinetics of biodegradation of mixture of substrates. Among the various models available for simulating the kinetics of biodegradation of multi-substrate systems, competitive inhibition model performed the best. Performance of the models was evaluated statistically using the dimensionless modified coefficient of efficiency (E). This model was used for simulating the kinetics of biodegradation in binary, ternary, and quaternary substrate systems. This study also reports batch experiments on co-metabolic biodegradation of chloroform, with acetone and toluene as primary substrates. The Haldane model, modified for inhibition due to chloroform, could satisfactorily predict the biodegradation of primary substrate, chloroform, and the microbial growth.

Biofiltration of Chloroform in a Trickle Bed Air Biofilter Under Acidic Conditions

“…In this study, ethanol is used as a cometabolite in combination with chloroform since it is a strong polar solvent and a simple straight chain alcohol. Both compounds are often emitted in a mixture by pharmaceutical industries and wastewater sources (Balasubramanian et al 2011;Cecen and Aktas 2011). Balasubramanian et al (2011) studied the aerobic biodegradation rates of different organic solvents like methanol, ethanol, isopropanol, acetone, acetonitrile, and toluene in individual batch systems.…”

“…Both compounds are often emitted in a mixture by pharmaceutical industries and wastewater sources (Balasubramanian et al 2011;Cecen and Aktas 2011). Balasubramanian et al (2011) studied the aerobic biodegradation rates of different organic solvents like methanol, ethanol, isopropanol, acetone, acetonitrile, and toluene in individual batch systems. Ethanol was degraded in the least amount of time and also formed the maximum microbial growth rate of 0.0415/h.…”

Aerobic Degradation of Trichloroethylene by Co-Metabolism Using Phenol and Gasoline as Growth Substrates

“…Further increase in phenol concentration led to a reduction in TCE degradation. As for the reason for this reduction, the possible toxicity incurred by high phenol concentration was excluded since the OD 600 did not decline [16]. Further, the oxygen was not depleted, and an oxygen concentration of 3.96 mg/L was measured.…”

“…In order to deal with the possible combined pollution, Balasubramanian et al [16] recently checked the co-metabolic degradation of chloroform in binary, ternary and quaternary systems containing some non-chlorinated solvents commonly used in pharmaceutical industries, such as small alcohols, acetone, acetonitrile, and toluene, and they found the co-metabolic degradation of chloroform occurred in the presence of acetone and toluene. Another study checked the effect of chlorinated solvents on the microbial degradation of dioxane (a stabilizer for chlorinated solvents) and the simultaneous co-metabolism of the chlorinated solvents because of their co-occurrence in groundwater [17].…”

Toluene-styrene secondary acclimation improved the styrene removal ability of biotrickling filter

“…The environmental awareness of general public was rising gradually with development of the world [1]. The releasing of volatile organic compounds (VOCs) has been a serious environmental and health concern because of its contribution to global environmental effects [2]. A wide range of VOCs was released because organic solvents are used as raw materials in pharmaceutical industries [3].…”