High efficiency degradation of tetrahydrofuran (THF) using a membrane bioreactor: identification of THF-degrading cultures of Pseudonocardia sp. strain M1 and Rhodococcus ruber isolate M2.
A mixed microbial culture capable of growing aerobically on tetrahydrofuran (THF) as a sole carbon and energy source was used as the inoculum in a 10 l working volume membrane bioreactor. Following start-up, the reactor was operated in batch mode for 24 h and then switched to continuous feed with 100% biomass recycle. On average, greater than 96% of THF fed to the reactor was removed during the 8-month study. THF loading rates ranged from 0.62 to 9.07 g l(-1) day(-1) with a hydraulic retention time of 24 h. THF concentrations as high as 800 mg/l were tolerated by the culture. Biomass production averaged 0.28 kg total suspended solids/kg chemical oxygen demand removed, i.e., comparable to a conventional wastewater treatment process. Periodic batch wasting resulted in a solids retention time of 7-14 days. Reactor biomass typically ranged from 4 to 10 g/l volatile suspended solids and the effluent contained no solids. Pure THF-degrading cultures were isolated from the mixed culture based on morphological characteristics, Gram-staining and THF degradation. Based on 16S rDNA analysis the isolates were identified as Pseudonocardia sp. M1 and Rhodococcus ruber M2.
Daye
K J
KJ
Environmental Projects Laboratory, Merck, Elkton, VA 22827, USA. kevin_daye@merck.com
Groff
J C
JC
Kirpekar
A C
AC
Mazumder
R
R
D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism; D005663:Furans / Q000378:metabolism*; D012240:Rhodococcus / Q000145:classification / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*
D005663:Furans; D012722:Sewage; C018674:tetrahydrofuran; D002244:Carbon