In ternationa l Scholars Journa ls African Journal of Food Science Research ISSN 2375-0723 Vol. 6 (9), pp. 378-381, September, 2018. Available online at www.internationalscholarsjournals.org © International Scholars Journals Author(s) retain the copyright of this article. Full Length Research Paper A study of mushroom species using sawdust of different economic tree species Abbot O. Oghenekaro*, John A. Okhuoya and Emmanuel O. Akpaja Mushroom Biology Unit, Department of Plant Biology and Biotechnology, University of Benin, P. M. B. 1154, Benin City, Nigeria. Accepted 06 May, 2018 Lentinus squarrosulus (Mont.) Singer was cultivated on the sawdust of five economic tropical tree spe-cies; Chlorophora excelsa, Celtis zenkeri, Guera cedrata, Nesogordenia papaverifera and Brachystegia, collected during processing at the sawmill. The highest yield of fruiting bodies (16.17 ± 1.25 g) was observed on B. nigerica sawdust supplemented with 1% CaCO3, 1% sugar and 20% wheat bran. The lowest yield (4.56 ± 1.84 g), was observed on N. papaverifera sawdust without supple-mentation. The results of this study demonstrate that L. squarrosulus mushroom did not show any particular trend with increase in supplementation level. The study underscores the need for guided use of sawdust types along with the required appropriate supplements. Key words: Agro-industrial waste, bioconversion, cultivation, edible mushroom, sawmill waste. INTRODUCTION Production of edible mushrooms in Nigeria is almost at the level of commercialization. However, the practical field application of many laboratory results still leaves much to be desired. Many still depend largely on the mushrooms harvested from the wild. In Nigeria, many mushrooms are highly prized, not only as food but also in traditional medicine (Oso, 1977; Alabi, 1990). Lentinus squarrosulus (Mont.) Singer is one of the edible mushrooms very common in the southern part of Nigeria (Nicholson, 1989; Oso, 1975; Akpaja et al., 2003). The Ibo people of Nigeria have even devised a peculiar way of tenderizing the usually tough overripe fruit bodies by dressing it, robbing it with edible oil and thereafter wrapping it in leaves. The wrap will then be placed in a fire place. This mushroom is very popular in Nigeria and has been highly recom-mended for commercialization (Okhuoya, 1997). A study by Wuyep et al. (2003) on this mushroom indi- cated its production of lignin and cellulose degrading enzymes. It is also reported to be widespread throughout equatorial Africa, South-East Asia, the Pacific Islands and Australia (Neda and Noi, 1998). Despite the widespread acceptance of this mushroom as an edible species in *Corresponding author. Email-abbotkaro@yahoo.com. Tel.: +2348036362036; Fax: +23452602370 Nigeria, there is lack of information about its cultivation. More importantly cultivation on sawdust being the most readily available and cheapest organic waste in Nigeria has not been investigated. This study reports on the cultivation of this mushroom species using sawdust of different economic tree species. MATERIALS AND METHODS Spawn preparation Pure L. squarrosulus (strain LS001UBNIG) was obtained from the Mushroom Biology Unit of the Department of Plant Biology and Biotechnology, University of Benin, Benin City, Nigeria. The spawn was prepared using Sorghum (Sorghum bicolor) grains as sub- strate. Empty salad cream bottles (275 ml) (readily available as dis- cards) were filled with parboiled sorghum grains (75% water) to three quarter full and covered with cotton wool. The bottles were autoclaved at a temperature of 121°C and 1.05 Kgcm 2 pressure for 20 min, allowed to cool down overnight and were inoculated. The inoculated grains were incubated at room temperature (25°C). After the grains have been fully colonized, they were kept in the refrigerator (5°C) until used. Collection of substrates Sawdust from the following economic trees; Chlorophora excelsa (Welw.) Benth. (Moraceae), Celtis zenkeri Engl. (Ulmaceae), Guera cedrata (A.Chev.) Pellegr. (Moraceae), Nesogordenia papaverifera (A. Chev.) R. Capuron (Sterculaceae) and Brachystegia nigerica Oghenekaro et. al. 379 Table 1. Effect of sawdust type on the time of Lentinus Squarrosulus mycelial colonization. Substrate mixture Time of full mycelial colonization (days) C1 C2 10% WB 20% WB Chlorophora excelsa 13.80±2.35* 9.80±0.58 17.50±6.50 17.00±0.00 Celtis zenkeri 9.60±0.51 7.80±0.49 13.00±0.58 N.A Guera cedrata 10.40±0.68 9.60±0.51 13.40±2.16 16.33±2.91 Nesogordenia papaverifera 10.20±0.37 10.25±0.25 12.75±1.93 15.00±0.00 Brachystegia nigerica 10.00±0.32 10.00±0.78 16.67±0.33 17.00±0.00 *= Mean of five replicates ± standard error. C1 = 100% sawdust C2 =98% sawdust, 1% CaCO3, 1% sugar. 10% WB = 88% sawdust, 10% wheat bran, 1% CaCO3, 1% sugar. 20% WB = 78% sawdust, 20% wheat bran, 1% CaCO3, 1% sugar. N.A = Not available. Hoyle and A. P. D. Jones (Fabaceae) were obtained during timber processing from Uwasota sawmill, Benin City, Nigeria. Wheat bran was bought from an animal Feed Dealer at textile mill road stores in Benin City. Calcium carbonate (CaCO3) was bought from a chemi- cal dealer while sugar was bought at Uselu Market Benin City. Sawdust and wheat bran were sun dried on daily basis. It was done in such a way that the layer of material was not thicker than 4 cm allowing its proper and even drying. Both materials were mixed regularly during the process. Substrate preparation The experiment had two controls. In order to determine if the sup- plement addition, will affect the mushroom’s growth and develop- ment. The first control (C1) was just the individual sawdust types measured into the cellophane bag on 300 g oven dry weight basis. The second control (C2) was set up by supplementing each saw- dust type with 1% calcium carbonate and 1% sugar. Two different treatments were prepared. The first treatment (10% wheat bran) was done by supplementing each sawdust with 1% CaCO3, 1% sugar and 10% wheat bran. The second treatment (20% wheat bran) was supplemented with 1% CaCO3, 1% sugar and 20% wheat bran. Moistened sawdust (300 g) oven dry weight and 75% water was loaded into a polythene bag (15 x 30 cm). Five replicate bags (15 x 30 cm) were prepared for each treatment. Thereafter, polyvinyl chloride ‘neck’ (5 wide x 3 cm long) was passed through the filled bag and the mouth of the bag covered with cotton wool. Bags were steamed for three hours on two con- secutive days. Substrate spawning and Incubation After cooling bags were randomly picked up and inoculated with mushroom spawn at 5% spawn level (Quimio et al., 1990). Spawned bags were incubated for 30 days in a clean room well shaded from direct sunlight and protected from the infiltration of rodents and other pests. Fruit body induction, harvesting and post harvest handling Fruit body induction was achieved by reducing the temperature of the environment by spraying water into the room and opening of the mouth of the bag, followed by spraying water on the surface of the substrates. Fruiting bodies were harvested four days after primor- dial emergence. Fresh weight of each harvest/flush was recorded. Mushrooms were dried at 105°C for 48 h, cooled in desiccator and their weight determined. Analysis of data This was done by determining the mean and standard error for each parameter. Analysis of variance was calculated for each set of data. The experiment, comprising five types of sawdust and two supplement levels (10 and 20% WB) was replicated five times in a completely randomized design. RESULTS AND DISCUSSION L. squarrosulus mycelium was able to colonize the differ- rent sawdust types irrespective of the supplementation level. The only exception to this observation was found in the 20% WB sawdust of C. zenkeri (Table 1). This excep- tion may have occurred due to an imbalance in the Car- bon/Nitrogen ratio required for mycelial growth (Chang, 1978) . The fastest mycelial colonization of (7.8 ± 0.49 days) was observed in (C2) C. zenkeri sawdust mixture, while it took as long as 17.50 ± 6.50 days for the mush- room to completely colonize the 10% WB sawdust of C. excelsa (Table 1). This result suggests C. zenkeri saw- dust with minimal upgrading (1% CaCo3 and 1% sugar) is more appropriate for mycelial growth of L. squarrosulus. The differences in the treatments as per total time of colonization were significant (p = 0.05). Primordial emergence was first observed in the pure B. nigerica sawdust after 20.60 ± 0.06 days (Table 2) whereas the longest time of primordial emergence was found in N. papaverifera 20% WB. The differences in the mean time for first primordial emergence were significant (p = 0.05). Mean fresh weight of dry fruiting bodies ranged from 16.17g ± 1.25 g in B. nigerica (20% WB) to 4.56g ± 1.84 g in N. papaverifera (C2). The differences in dry fruiting bodies yield (Table 3) on different sawdust and sup- plement combinations were significant (p = 0.05). The highest organic matter loss due to the activity of the mushroom on the different sawdust substrates with their 380 Afr. J. Food Sci. Res. Table 2. Effect of Substrate Supplementation on the first time of primordial emergence (days). Substrate mixture C1 C2 10% WB 20% WB Chlorophora excelsa 31.00±4.04* 27.30±2.85 34.00±0.00 35.33±2.40 Celtis zenkeri 25.40±0.51 27.40±1.91 30.50±3.18 N.A Guera cedrata 31.25±0.85 28.20±0.74 39.00±2.00 33.67±0.33 Nesogordenia papaverifera 23.50±2.18 21.67±1.20 34.75±0.75 41.00±1.00 Brachystegia nigerica 20.60±0.16 22.25±1.60 39.00±0.71 42.00±1.00 *= Mean of five replicates ± standard error. C1 -100% sawdust C2- 98% sawdust, 1% CaCO3, 1% sugar. 10% WB-88% sawdust, 10% wheat bran, 1% CaCO3, 1% sugar. 20% WB-78% sawdust, 20% wheat bran, 1% CaCO3, 1% sugar. N.A = Not available. Table 3. Sporophore yield of Lentinus squarrosulus cultivated at different supplementation levels. Substrate mixture Supplementation with wheat bran (%) C1 C2 10% WB 20% WB Chlorophora excelsa 15.93±0.98* 6.72±2.21 12.70±0.00 9.69±1.78 Celtis zenkeri 15.97±2.17 16.02±2.21 11.17±2.97 N.A Guera cedrata 6.60±2.23 6.36±1.30 12.13±0.00 13.01±1.44 Nesogordenia papaverifera 4.56±1.84 7.16±3.17 14.85±0.65 14.70±0.60 Brachystegia nigerica 12.65±2.42 12.41±2.53 12.56±0.70 16.17±1.25 * = Mean of five replicates in grams. C1 -100% sawdust C2- 98% sawdust, 1% CaCO3, 1% sugar. 10% WB-88% sawdust, 10% wheat bran, 1% CaCO3, 1% sugar. 20% WB-78% sawdust, 20% wheat bran, 1% CaCO3, 1% sugar. N.A = Not available. Table 4. Percent organic matter loss due to the production of Lentinus squarrosulus on sawdust of selected economic trees. Substrate mixture Level of wheat supplementation (%) C1 C2 10% WB 20% WB Chlorophora excelsa 19.93* 33.96 13.88 10.86 Celtis zenkeri 29.23 21.61 25.53 13.07 Guera cedrata 21.51 32.59 33.51 12.66 Nesogordenia papaverifera 28.86 24.99 15.06 15.85 Brachystegia nigerica 25.19 16.33 29.19 15.96 *= Mean of five replicates. C1 -100% sawdust C2 - 98% sawdust, 1% CaCO3, 1% sugar. 10% WB-88% sawdust, 10% wheat bran, 1% CaCO3, 1% sugar. 20% WB-78% sawdust, 20% wheat bran, 1% CaCO3, 1% sugar. N.A = Not available. their respective supplement ranged between 33.97% in C. excelsa (C2) and 12.66% in G. cedrata 20% WB mix- ture (Table 4). L. squarrosulus (Mont) singer grew successfully with sporophore production on the various sawdust types. Different treatments and controls gave different results. This may be due to effective substrate utilization (Can-. non, 1986; Laborde, 1992) in several substrate mixtures. The results of this study indicate that even though saw- dust is readily available and cheap, there is the need to be guided regarding its sources. This is necessary because sawdust type strongly influences mushroom yield. Also, as shown by Royse et al. (1990), amendment of synthetic substrates may enhance mushroom yield. Oghenekaro et. al. 381 Also, an ethno- knowledge obtained from some indivi- duals in sawmills suggests that there is the need to be cautious in the use of Berlinia sp. sawdust. It is believed that this tree imparts toxicity to edible mushrooms (per- sonal communication). At least, two individuals claim they had seen persons affected with some ailments eating mushrooms grown on this type of wood. A study on the empirical confirmation of this ethno-knowledge is on- going and will be reported in the nearest future. It may be necessary to conduct further research into the use of local sawdusts for cultivation of this mushroom specie so as to increase the yield. ACKNOWLEDGEMENT Uwasota sawmill workers are highly acknowledged for providing sawdust. REFERENCES Akpaja EO, Isikhuemhen OS, Okhuoya, JA (2003). Ethnomycology and usage of edible and medicinal mushrooms among the Igbo people of Nigeria. In. J. Medicinal Mushrooms. 5: 313-319. Alabi RO (1991). Mycology and Nigerian culture: Past, present and future. In: proceeding of the first conference on African mycology. Mauritius, 10(15):13-52. Alexander HS (1978). Morphology and classification of edible mushrooms In: Chang, S.T and Hayes, W.A. (eds). The biology and cultivation of edible mushrooms: Academic Press, New York, p. 819. Cannon PF (1986).International Commission on the Taxonomy of fungi (ITCF): name changes in fungi of microbiological, industrial and medicinal importance. Part 1. Microbiological Science 3: 168-171. Laborde J (1992). Required qualities of indoor composition. Mushroom World. 3: 23-30. Neda H, Doi Y (1998). Notes on Agarica in Kyushu district!! Memoirs of the National Science Museum, No 31, Tokyo. pp. 89-95. Nicholson RA (1989). Common mushrooms found in Akwa Ibom state. The Nigerian field. 54: 19-32. Okhuoya JA. (1997). Mushroom cultivation: The Nigerian experience. In: food processing technologies for Africa. Hamid Dirar A (ed). Emerging Technologies series. United Nations Industrial Developing organization, Vienna. p. 196. Oso BA (1975). Mushroom and Yoruba people of Nigeria.Mycologia, 67: 311-319. Oso BA (1977).Pleurotus tuber-regium from Nigeria.Mycologia, 69: 271- 279. Quimio TH, Chang ST, Royse DJ (1990). Technical guidelines for mushroom growing in the tropics, Plant production and protection paper 106. Food and Agriculture Organization, Rome, 1: 55. Royse DJ, Bahler BD, Bahler CC(1990). Enhanced yield of shitake by saccharine amendment of the synthetic substrate. Appl. Environ. Microbiol.56: 479-482. Stamets P (2002a). Growing gourmet and medicinal mushrooms. 3 rd Edition. Ten Speed Press Berkerly. p. 574. Stamets P (2002b). Mycomedicinals. An informational treatise on mushrooms. 3 rd Edition.MycoMedia Productions, Olympia. p. 96. Wuyep PA, Khan AU, Nok AJ (2003). Production and regulation of lignin enzymes from Lentinus squarrosulus (Mont) Singer and Psathyrella atroumbonata Pegler. Afr. J. Biotechnol. 2: 444-447.