73 USM R & D 18(1): 73-76 (2010) ISSN 0302-7937 Growth and yield performance of oyster mushroom (Pleurotus ostreatus) feeding on different agro-industrial wastes Catherine Hazel M Aguilar, Joey Real Marie I Barbosa, Florence Lasalita- Zapico, & Remedios S Flamiano Science Department, College of Science and Mathematics, Mindanao State University, Fatima, General Santos City, Email: forence.zapico@gmail.com Tel no. (6383) 380-6555 Abstract This study aimed to determine which of the three common agro-industrial wastes, namely, rice hulls, fresh coco coir, and banana leaves, is the best substrate for oyster mushroom culture. Data gathered were on the number of days for complete mycelial growth, appearance of pinheads and the maturation of fruiting bodies, the number of fruiting bodies, size of individual mushrooms, and total yield. Data analysis using ANOVA showed signifcant differences between substrates. Results revealed that rice hull substrate was the best for oyster mushroom cultivation since it manifested positive results for all parameters evaluated. As for the coir dust substrate, mushroom growth did not progress past the spawn running stage. Possible explanations to this are the high salinity and phenolic content, high nitrogen immobilization, and the high C:N ratio in coco coir. This cessation of growth in the coir could be explained by the phytotoxic effects of the phenolic compounds. It is suggested therefore that coco coir should be used with caution and that it should be pre-processed before use as substrate for mushroom production. Key words: Agro-Industrial wastes, oyster mushroom, phenolics, phytotoxicity, Pleurotus ostreatus Introduction Oyster mushroom (Pleurotus ostreatus) is an edible basidiomycete which is widely grown all over Asia. It is used in the preparation of many continental dishes and is purported to have medicinal properties. It is generally believed that this particular species of mushroom provides therapy for patients suffering from many forms of cancer and high cholesterol levels. Oyster mushroom is also one of the few known carnivorous mushrooms whose mycelia can kill and digest nematodes. This is an adaptive mechanism which enables them to obtain nitrogen in swampy soils, tree trunks, and other nitrogen-poor substrates. This protein- extracting ability of oyster mushrooms also makes them a very popular alternative energy source for dieting individuals (Shah 2004). A signifcant portion of farm wastes is thrown away or left to rot in the felds. These organic wastes (straws, leaves, roots, fruits, etc) can be recycled in several ways so that the environment may be relieved of pollution. One such alternative is using these organic wastes for oyster mushroom cultivation. These mushrooms thrive well in many lignocellulosic materials. Digestion of these materials yields glucose and other forms of sugars (Vetayasuporn 2006). Since many sugars are released which are converted onto sources of carbon when digested, lignocellulosic materials are likely to be used as substrates for P. ostreatus cultivation. Materials and methods Substrate preparation and spawn inoculation The substrates were soaked in water mixed with urea for three days, drained, and allowed to ferment for fve days prior to spawn inoculation. Plastic bags (18 x 25 cm) were halfway flled with the three different substrates and their openings were stuffed with cotton plugs. These plugs served as ventilation holes while keeping out harmful organisms and contaminants. The substrate bags were pricked with pins for aeration and for the occasional moistening of the developing mushrooms. The bags were then autoclaved at 121 o C at 15 lbs psi. Oyster mushroom spawn were then inoculated into the three different substrates under complete darkness. The room was kept closed until the mycelia were widespread. Experimental set-up and data analysis This experiment was laid out in a Completely Randomized Design (CRD) with the three substrates as treatments and with fve replications. Growth parameters such as the number of days for complete mycelial growth, appearance of pinheads, and the maturation of fruiting bodies were recorded. Data on the number of fruiting bodies, size of individual mushrooms, and total yield were also collected.