Cultivation of oyster mushrooms (Pleurotus spp.) on various lignocellulosic wastes Q.A. Mandeel*, A.A. Al-Laith and S.A. Mohamed Department of Biology, College of Science, University of Bahrain, P.O. Box 32038, Isa Town Campus, Kingdom of Bahrain *Author for correspondence: Tel.: +973-876417, Fax: +973-876519, E-mail: qmandeel@sci.uob.bh Keywords: agriculture waste, bagging systems, fungi, lignocellulosic, oyster mushroom, Pleurotus, spawn Summary Cultivation of speciality mushrooms on lignocellulosic wastes represents one of the most economically and cost- effective organic recycling processes. Three species of Pleurotus, namely P. columbinus, P. sajor-caju and P. ostreatus were experimentally evaluated on untreated organic wastes including chopped office papers, cardboard, sawdust and plant fibres. Production studies were carried out in polyethylene bags of about 1 kg wet weight with 5% spawning rates of substrate fresh weight in a custom-made growth room especially designed for spawn run and cropping. The conversion percentage from dry substrate weight to fresh mushroom weight (biological efficiency) was determined. The highest biological efficiency was noted with P. columbinus on cardboard (134.5%) and paper (100.8%), whereas P. ostreatus produced maximum yield on cardboard (117.5%) followed by paper (112.4%). The overall yield of P. sajor-caju was comparatively low (range 47–78.4%). The average number of sporophore flushings ranged between 5 and 6 times. The findings that P. columbinus and P. ostreatus are superior to P. sajor-caju are consistent with previous reports elsewhere. Further evaluation of P. columbinus alone on different bagging systems containing partially pasteurized office papers as a growing substrate revealed that polyethylene bags resulted in 109.4% biological efficiency in contrast to pottery (86%), plastic trays (72%) or polyester net (56%). The above findings reveal an opportunity for commercial implication of oyster mushroom especially P. columbinus for utilization of different feasible and cheap recyclable residues. Introduction Pleurotus species, commonly known as oyster mush- rooms, are edible fungi cultivated worldwide especially in south east Asia, India, Europe and Africa. The genus is characterized by its high protein content (30–40% on dry weight basis) (Sharma & Madan 1993) and gourmet food quality, thus surpassing many other foods. Medically, Pleurotus ostreatus is reported to decrease cholesterol levels in experimental animals (Bobek et al. 1995; Bobek et al. 1998; Hossain et al. 2003). Unlike other mushroom species, oyster mushrooms are the easiest, fastest and cheapest to grow, require less preparation time and production technology. Also, the first flush is usually large, without the need for compost, manure, limestone, casing or temperature shocks. With more than 100% biological efficiency, coupled with its distinctive flavour, aroma and excellent drying and preservation qualities, it is assured a unique status as a delicacy. Bioconversion of lignocellulosic residues through cul- tivation of Pleurotus species offers the opportunity to utilize renewable resources in the production of edible, protein-rich food that will sustain food security for people in developing countries (Sanchez et al. 2002). Cultivation of edible mushrooms is one of the most economically viable processes for the bioconversion of lignocellulosic wastes (Bano et al. 1993; Cohen et al. 2002). The tech- nology can also limit air pollution associated with burning agriculture wastes as well as to decrease rodents, pests and deleterious fungal inoculum populations. Various agricultural by-products are being used as substrates for the cultivation of the oyster mushroom. Some of these wastes include banana leaves, peanut hull and corn leaves, mango fruits and seeds, sugarcane leaves, wheat and rice straw (Cangy & Peerally 1995). The widely used substrate for cultivation of the oyster mushroom in Asia is rice straw (Thomas et al. 1998). It is also considered the best substrate in terms of yield and high protein content. In Europe, wheat straw is used, while in South East Asian countries sawdust is more common. The majority of these substrates can be used as animal feed. However, their low digestibility, low protein content and high lignin content render them unpopular and unacceptable. Moreover, due to an increased demand on these substrates for biogas pro- duction, composting and non-availability in some areas, it becomes necessary to find cheap alternative sources. In Bahrain, cultivation of the date palm results in the accumulation of large quantity of by-product leaves which are rich in lignin and cellulose and are available World Journal of Microbiology & Biotechnology (2005) 21:601–607 Ó Springer 2005 DOI 10.1007/s11274-004-3494-4