Effects of Chitin on Microbial Emulsification, Mineralization Potential, and Toxicity of Bunker C Fuel Oil

Abstract

Bunker C, one of the most frequently spilled petroleum products in the US, is difficult to remove from oiled surfaces and is relatively recalcitrant to biodegradation; therefore, emulsification and biodegradability must be optimized before bioremediation can be considered a viable treatment option. Sand from a freshly oiled beach near Dutch Harbor, Alaska, was incubated at 10°C with nutrients (Bushnell–Haas (BH)) or nutrients with crab shell chitin (BH-C). BH-C amendment resulted in greater numbers of bunker C emulsifiers and greater mineralization potentials for hexadecane, phenanthrene, and fluorene than with BH only. Compared to BH alone, mineralization potentials for bunker C also were higher in BH-C, with an estimated 8% of fuel oil mineralized after 6 weeks. Microbially emulsified oil was more toxic than in uninoculated controls (p<0.05) as measured by Microtox® assays. However, toxicity was significantly lower in BH-C than BH after 4 and 6 weeks incubation (p<0.05).