Digitaria decumbens Grass Substrate Prepared by Alkaline Immersion for Culture of Pleurotus spp.

Corncobs or corn straw, or mixtures thereof, treated in alkaline water (0.5% calcium hydroxide) are the traditional ingredients used in Chiapas, Mexico to prepare substrate for the cultivation of Pleurotus spp. However, due to suboptimal yields obtained with these raw materials, experiments were conducted in an attempt to increase biological efficiency. Substrates prepared with grass (Digitaria decumbens), alone or in combination with coffee pulp, were used to produce P. ostreatus. Grass alone showed promise as a substrate, with yields increasing by as much as 34% over corn straw alone and more than double that of corncob substrate. Coffee pulp added to grass did not increase yield over corn straw alone. A trial for testing supplements (fish meal, wheat bran and ground soybean) was performed using five strains of P. ostreatus or P. pulmonarius grown on a traditional corncob substrate. The addition of 6% ground soybean meal (treated with formaldehyde or calcium hydroxide) to traditional substrate resulted in a 38% yield increase compared to non-supplemented substrate. The magnitude of the yield response to ground soybean supplement was influenced by the mushroom strain used. eng