While, after fermentation data in Table 2 showed that the total amounts of macro and micro nutrients were increased in spent straw compost when compared with raw maize stalks. The most increase was recorded for potassium and magnesium. The increment of nutrients in spent mushroom might be due to effect of the fungal growth as reported by Mohammady, 1996 and Bakr A.A. 2009, 2009. Or to the tap water used during fungal growth which contain K, Mg, and Ca reported by Dina Anwar et al. (2009).
Bioconversion of maize stalks to protein enriched by-product using mixed culture of white rot fungi and S. cerevisiae through solid sate fermentation process is shown in Table 3.
Table 3.
Biological treatment of maize stalks using Pleurotus ostreatus and different inoculum size of Saccharomyces cerevisiae inoculums (incubation at 28 °C for 7, 14, 21 and 28 days).