Growth of Chlorinated Solvent‐Degrading Consortia in Fed‐Batch Bioreactors and Development of a Double‐Substrate High‐Performing Microbial Inoculum

Abstract

The long-term growth process of two microbial consortia effective in the aerobic cometabolic biodegradation of a mixture of 6-chlorinated aliphatic hydrocarbons (CAHs), the effectiveness of these consortia as inocula for the bio-augmentation of different types of microcosms and the development of a double-substrate, highperforming consortium is presented. The propane-utilizing consortium generally proved to be the most effective one, being able to biodegrade vinyl chloride, cisand trans-1,2-dichloroethylene, trichloroethylene, 1,1,2-trichloroethane and 1,1,2,2-tetrachloroethane at all the CAH concentrations tested (0-4 lM). Both consortia maintained unaltered CAH degradation capacities over a 300-day growth period in the absence of the CAHs and were effective in inducing the rapid onset of CAH depletion upon inoculation in slurry microcosms set up with five types of aquifer materials. A consortium supplied with both methane and propane combined the best degradation capacities of the two single-substrate consortia, and maintained stable performances for 150 days under slurry conditions. The degree of conversion of the organic Cl to chloride ions was equal to 90 %.

Aerobic co‐metabolism of 1,1,2,2‐tetrachloroethane by Rhodococcus aetherivorans TPA grown on propane: kinetic study and bioreactor configuration analysis

“…Complete anaerobic biodegradation and detoxification of TeCA was described with consortia containing multiple dehalorespiring microorganisms whereas pure strains were reported to be able to degrade TeCA incompletely . On the other hand, in recent years a limited number of studies demonstrated the possibility to biodegrade TeCA via aerobic co‐metabolism using mixed cultures . Further, some studies have characterized both aerobic and anaerobic microbial communities able to degrade TeCA for bioaugmentation purposes in the light of a bioremediation strategy …”

“…3,14 On the other hand, in recent years a limited number of studies demonstrated the possibility to biodegrade TeCA via aerobic co-metabolism using mixed cultures. 2,13,15,16 Further, some studies have characterized both aerobic and anaerobic microbial communities able to degrade TeCA for bioaugmentation purposes in the light of a bioremediation strategy. 2,12,17,18 Methane, toluene, phenol, ammonia, propane and butane have been effectively utilized as growth substrates for bacterial CAH aerobic co-metabolism.…”

Chloroform aerobic cometabolic biodegradation in a continuous‐flow reactor: Model calibration by means of the gauss‐newton method

“…Among these, AC represents a promising option. Indeed, numerous studies have shown that it can lead to the rapid biodegradation of all the CAHs except the fully chlorinated ones, such as tetrachloroethylene and carbon tetrachloride . AC can also biodegrade flame retardants and pharmaceuticals .…”

Efficacy of pentane, toluene, and benzene to support aerobic cometabolism of ethylene dibromide

“…Previous studies have demonstrated aerobic cometabolism of chlorinated alkanes, alkenes, and fuel additives such as MTBE by microorganisms grown on a variety of primary substrates, such as methane, propane, butane, toluene, benzene, pentane, and phenol [1][2][3][4][5]. In comparison, little is known about the cometabolism of brominated organic compounds, which may also be present at some contaminated sites.…”