Isolation and enrichment of thermo- and alkali-tolerant oil-degrading bacteria

Abstract

Water is an indispensable resource for human beings the conservation of water resource is an important issue Biotreatment process can potentially improve the treatment efficiency of conventional physico-chemical treatment However the biological treatment systems in extreme environments especially in many industrial wastewater treatment plants are vulnerable One of the strategies is bioaugmentation a process of adding selected strains/mixed cultures to environment or system In this study isolates B-1 B-4 D-2 E-1 and G-1 that with thermo- and alkali-tolerant ability and can use cold rolling oil as sole carbon and energy source were isolated Isolate B-1 and D-2 reached 80 and 77 5% total petroleum hydrocarbons (TPH) removal at pH 9 45°C with initial TPH concentration of 1450 mg L-1 within 14 d of incubation To scale up Chelatococcus sp ES-SL-4 removed 75% of COD and 69 2% of TPH in 6 d in a 5-L bioreactor showing the ability to degrade cold rolling oil and use it as sole carbon and energy source In the mixed-cultural experiments the batch inoculating with enriched sludge had the best degrading performance which had accumulated 38 3 mL of CO2 in headspace and transferred 1053 mg L-1 of TPH (62 0% of removal) The occurrence of unculturable consortia in enriched sludge participate the degradation of cold rolling oil To sum up this study demonstrates the potential to degrade wastewater containing cold rolling oil in alkaline and thermophilic environment

Date of Award	2019
Original language	English
Supervisor	Liang-Ming Whang (Supervisor)