The assessment of apple pomace as a basic substrate and a nutrient supplement for Oyster mushroom (Pleurotus ostreatus) cultivation in Bhutan

This study assessed the potential of using apple pomace waste as a substrate and nutrient for Pleurotus ostreatus cultivation. Paddy straw, a common substrate for P. ostreatus in Bhutan, was used as a control. In the case of using apple pomace as a substrate, the yield of 120 g/bottle in two strains was statistically more significant than the control (α = 0.01), achieving yield-increase ratios of 50 % and 36 % compared to the control substrate yields of 80 g/bottle and 88 g/bottle in each strain. The yield from 135 tons of apple pomace wasted by a company in a year in Bhutan was estimated to be 39 tons, using a 29 % yield conversion rate per unit weight of apple pomace. The waste from the used substrate of apple pomace was calculated at 71 tons in wet weight, and the waste-reduction ratio of apple pomace was 47 % due to P. ostreatus cultivation. In the case of using apple pomace as a nutrient for paddy straw substrate, 124 g/bottle and 119 g/bottle of yield in the 4 % supplementation substrate were statistically more significant than 101 g/bottle and 104 g/bottle of the control without supplementation (α = 0.05), representing yield-increase ratios of 23 % and 14 % compared to the control substrate for each strain. If 135 tons/year of apple pomace were used as a 4 % nutrient for paddy straw substrate, it is estimated that an annual harvest of 1,001 tons could be achieved using a 33 % yield conversion rate and 3,034 tons of substrate quantity. It was not observed to reduce the commercial value of fruiting bodies in both methods of using the basic substrate and nutrient for paddy straw substrate. It was concluded that both methods of utilizing apple pomace waste were practical for P. ostreatus cultivation and efficient in reducing waste quantity.