AXENIC CULTIVATION OF Pleurotus ostreatus var. Florida IN SUPPLEMENTED SUGARCANE BAGASSE BRIQUETTES

Engenharia Agrícola ISSN: 1809-4430 (on-line) www.engenhariaagricola.org.br Doi: http://dx.doi.org/10.1590/1809-4430-Eng.Agric.v38n6p835-843/2018 AXENIC CULTIVATION OF Pleurotus ostreatus var. Florida IN SUPPLEMENTED SUGARCANE BAGASSE BRIQUETTES Anderson C. Magalhães1*, Bruno R. de A. Moreira2, Diego C. Zied2 1* Corresponding author. College of Agricultural and Technological Sciences, São Paulo State University (Unesp)/ Dracena – SP, Brazil. E-mail: KEYWORDS ABSTRACT briquetting, bioconversion, edible mushrooms, productivity. Articles on the applicability of briquetting to the production of mushrooms are rare. Therefore, this research provides the scientific community and, mainly, producers, unpublished technical information regarding the productive yield of oyster mushroom cultivated in sugarcane bagasse briquettes supplemented with bioproducts of cereals. In 30 days of axenic cultivation, 6 tons-force briquettes with 80% humidity resulted in higher productivity (30.4%), and generated the lowest physical volume of exhausted compound (44.8%), thus, overcoming the technical performance of the other briquetting matrices tested, and even of methods traditionally used for the preparation of substrate for P. ostreatus cultivation on a commercial scale. The conclusion is, therefore, that the axenic cultivation of P. ostreatus var. Florida in sugarcane bagasse briquettes, supplemented with bioproducts of cereals, has technically qualified as an original and efficient method for the production of high biological value protein by the recycling of agricultural residues and can therefore guarantee multiple economic benefits to the agribusiness of the oyster mushroom, in addition to allowing reduction of environmental impacts by the restricted generation of exhausted compound in the post-harvest stage. INTRODUCTION In Brazil, an international reference in technology for sugar and bioethanol industrialization, a considerable physical volume of sugarcane bagasse is annually generated as a co-product by the sugar-energy sector; if it is disposed incorrectly to the environment, this generates irreparable adverse effects on native fauna and flora. Researches emphasize that this agricultural residue enables sustainable applications such as soil conditioner and cultivation substrate for edible mushrooms (Shu et al., 2015; Wang et al., 2017). Known as oyster mushroom, shimeji or hiratake, P. ostreatus qualifies as an excellent source of high biological value proteins, essential amino acids, vitamin D, macro and micronutrients, and carbohydrates, in addition to possessing low cholesterol. As for the cultivation and commercialization aspects, this does not require expensive investments in the installation and maintenance of production infrastructure; it adapts well to lignocellulosic substrates and has a guaranteed demand for vegan and vegetarian cultures. Therefore, the oyster mushroom agribusiness is considered profitable and ideal for non- capitalized producers (Bach et al., 2017; Khan et al., 2017). In P. ostreatus commercial cultivation, the substrate selection and preparation are crucial steps to productivity and product quality. If possible, we should opt for a substrate of excellent nutritional quality, easy to acquire, whose supply is regular and the source of production is located as close as possible to the place of cultivation. Although the enzymatic complex of P. ostreatus is an excellent degrader of complex carbohydrates such as cellulose, hemicellulose and lignin, it is possible that there is unproductivity in lignocellulosic substrates, if these are nutritionally inappropriate. For this reason, experts recommend supplementing them with rice, wheat and corn bran, bean leaves, or any other additional source capable of balancing the carbon/nitrogen ratio (C/N) (Naraian et al., 2016, Vieira & Andrade, 2016; Higgins et al., 2017). Added to the nutritional quality, the sanitary aspect and physical properties of substrate also considerably influence the productive yield of P. ostreatus. Traditionally, the substrate sterilization is promoted by thermal treatments such as pasteurization, composting and autoclaving, making it axenic, that is, free of harmful 2 São Paulo State University (Unesp)/ Dracena - SP, Brazil. Received in: 5-18-2018 Accepted in: 9-20-2018 Engenharia Agrícola, Jaboticabal, v.38, n.6, p.835-843, nov./dec. 2018 Anderson C. Magalhães, Bruno R. de A. Moreira, Diego C. Zied 836 microbial agents. Although this substrate category offers advantages to producers, such as little or no contamination propensity and accelerated cultivation cycle, the preparation of the substrate requires considerable volume of raw material, making it difficult the management of waste in the post-harvest stage. Scientific researches highlight the fight against excessive generation of mushroom drawn compound in post-harvest stage as one of the main challenges regarding the cultivation of P. ostreatus (Atila, 2016; Higgins et al., 2017). Therefore, it was assumed that the briquetting could be useful to the sustainability of the oyster mushroom production chain by the production of reduced volume substrate. Historically, the briquetting technology is applied to the industrialization of solid biofuels. Hence, it is less popular in relation to food production. In this technique, the density of the raw material is significantly reduced by compaction at constant pressure and temperature, with or without the presence of natural or synthetic binder substances. Due to its physicochemical properties and moderate nutritional quality, the sugarcane bagasse is simultaneously viable to the briquetting and production of culture substrate for oyster mushroom (Khorasgani et al., 2017). Therefore, it was verified the unavailability of articles that relate oyster mushroom production to briquetting, this research was conducted on axenic cultivation of P. ostreatus var. Florida in sugarcane bagasse briquettes, supplemented with cereal bioproducts, with the intention of disseminating unpublished information on viability of briquetting to the oyster mushroom crop and benefits that such technology could offer to fungus farmers, especially those with limited physical space for storage, preparation, cultivation and management of drawn compound. (Prismatec, line CS-A), at 121°C and 1 atm, for 30 minutes. Finally, the Petri dishes were conditioned in BOD incubator (Filterflux, photoperiod SL-224), maintaining them at 23.5 ± 2.7°C, for seven days (Tarko & Sirna, 2018). To the spawn production, 2 kg of sorghum grains were used. After cooking, promoted at 50°C for 1 hour, the grains were cooled in running water, then dried in the sun. To the grains, 20 g of agricultural gypsum were added in order to supplement them and, consequently, to provide nutrients to the mycelial development. The grains were distributed in polyethylene bags, to which a cotton filter was added, so that the water vapor was allowed dur (...truncated)