Effect of crude oil contamination on the yield and chemical composition of Pleurotus tuber-regium (Fr.) Singer.

Abstract

The effect of crude oil contamination which is a perennial problem in the Niger Delta of Nigeria on the yield and nutrient status of Pleurotus tuber-regium was investigated. In this study, after cultivating P. tuber-regium in crude oil contaminated soils to which sawdust, shredded banana leaf blades, NPK fertilizer and poultry litter were added, the yield and nutrient or chemical composition were determined. Crude oil contamination caused significant increase in the size and yield of the mushroom by increasing the pileus and stipe size and also fresh and dry weights showing a fertilizer effect. The addition of sawdust and poultry litter enhanced the fertilizer effect by further significant increases in size and yields of treatments that had them. The addition of NPK and shredded banana leaf blades to crude oil contaminated soils did not enhance the fertilizer effect of crude oil as there was significant decrease in the size and yield of P. tuber-regium in treatments that had them. The nutrient chemical composition of the mushroom was also affected by the presence of the crude oil and supplementation with the various materials. There was a reduction in the moisture and carbohydrate content caused by the addition of poultry litter and sawdust to the contaminated soils and an increase in the ash, fat, protein and fibre content of the mushroom. On the other hand, the addition of NPK and shredded banana leaf blades caused a reduction in the moisture, protein and carbohydrate content and an increase in the fat, moisture, ash and fibre content. The performance of the fungus in crude oil contaminated substrates can be optimized by the addition of sawdust and poultry litter but not shredded banana leaf blades and NPK. This is evident from the fact that sawdust and poultry litter enhanced growth while shredded banana leaf blades reduced growth in crude oil contaminated soil. The improvement in nutrient status of the mushroom indicates that the fertilizer effect of crude oil also affects the general well being of the fungus. Key words: Crude oil contamination, Pleurotus tuber-regium, fertilizer effect, nutrient status.