Abstract
The biodegradation of oil in wastewater by bioremediation method of combining Yarrowia lipolytica (Bioaugmentation) with some water-soluble vitamins (Biostimulation) was investigated. It was found that as olive oil was used only as a substrate the strain is able to grow and the degradation rate of the oil in the model wastewater is faster than that by using general activated sludge. Moreover, when the strain is added into general activated sludge, the degradation rate of oil is fast compared with the case of the strain only. As a result, it turned out that the bioaugmentation to add fat-degradating yeast into wastewater was effective. On the other hand, it is known that several kinds of vitamins are indispensable to degrade fat but those vitamins are very little in the wastewater. Then, we examined the additive effect of the vitamin to the fat degradation. When several vitamins (thiamin, pantothenic acid, biotin etc.) were added into the model wastewater, the degradation rate of oil is faster than that without vitamins. As results, it was turned out that β-oxidation and/or TCA cycle in microorganism existing in activated sludge are activated by the biostimulation method adding a small amount of vitamins into wastewater. Now, we are examining the efficient degradation of the oil into wastewater by a new bioremediation method that combines bioaugmentation with biostimulation.
