Physico-chemical and Culture-dependent Microbiological Characterization of Spent Pleurotus Composts from Three Different Agro-based Wastes

Abstract

Aim: Physico-chemical and culture-dependent microbiological properties of spent mushroom compost (SMC) were investigated. Study Design: The physico-chemical and microbiological properties of spent mushroom composts were determined using standard methods. Place and Duration of the Study: The study was conducted at the Department of Biotechnology, Federal Institute of Industrial Research, oshodi, Lagos-Nigeria between September to December, 2012. Results: The CW-SMC, SD-SMC, and BSG-SMC, had a total nitrogen content of 30.52 mg/Kg, 22.54 mg/Kg, and 14.20 mg/Kg, respectively while total phosphorus was observed as 14.10 mg/Kg, 12.45 mg/Kg, and 6.45 mg/Kg, respectively. In all the SMC’s studied, Ca had the highest concentration (5.30-6.60 meq/100 g) among other exchangeable cations. The concentrations of Pb, Vn, Fe, Cr, and Ni were within the range of 0.02 mg/kg-8.93 mg/kg but BSG-SMC had the least concentrations of heavy metals. Quantitative compost microbiological analyses showed heavy loads of total culturable hydrocarbon utilizing bacteria (1.8-11 x 104cfu/g) and fungi (4.4-8.5 x 104cfu/g) counts. Hydrocarbon utilizing microorganisms associated with the SMC’s were: Penicillium sp., Aspergillus niger, Pleurotus ostreatus, Bacillus amyloliquefaciens, Bacillus subtilis, Bacillus licheniformis, and Burkholderia species. Conclusion: SMC’s are good sources of limiting nutrients and hydrocarbon degrading microorganisms.