Biodegradation of crude oil hydrocarbons by a newly isolated biosurfactant producing strain

Abstract

New bacterial strain BN66 was isolated by selective enrichment, identified as Bacillus cereus and proved to degrade crude oil, together with biosurfactant synthesis. Free and cryogel immobilized Bacillus cereus cells were involved in a crude oil degradation process. The studied strain degraded 93% of the aliphatic fraction for 48 h. We immobilized cells in two types of cryogels synthesized from high molar mass polyacrylamide or acrylamide precursors and explored the degradation capability and possibility for re-use of the preparations. Reusability tests revealed that the oil degradation ability of immobilized cells was stable after 47 days (28 °C and shaker speed 120 rpm) and the degradation rate of immobilized cells was maintained at a high level up to the 20^th cycle of operation. The matrices obtained from high molar mass polyacrylamide appeared to be more suitable due to their ability to keep the cells within the carrier. The cells immobilized in cryogels exhibited more effective degradation for 22 active cycles at semicontinuous mode of operation compared to only three cycles performed by free cells.

Keywords:

• Bacillus cereus
• biosurfactant
• immobilization
• biodegradation

Disclosure statement

The authors have no financial conflicts of interest to declare.

Additional information

Funding

This work was supported by the National Fund for Scientific Research, Republic of Bulgaria, under Grant DN 11/2.