Biological efficiency and nutritional value of Pleurotus ostreatus cultivated on spent beer grain

Unpretreated spent beer grains were successfully used as a basic substrate material for the cultivation of Pleurotus ostreatus. The effects of spent g rain types, additives, substrate moisture content, and substrate packing de nsity on the yield and nutrition of fruit bodies were investigated. The cul tivation results showed that few fruit bodies were formed on spent grain al one; however, a significantly high biological efficiency (19.1%) was obtain ed with the addition of wheat bran to (45%). The chemical analysis of fruit bodies indicated that P. ostreatus cultivated on spent grain substrate had a higher nutritional value than those grown on other reported types of sub strates. The total amino acid content in the fruit bodies was 347.5 mg/g dr y matter, and the crude protein content was as high as 53.3%, on a dry weig ht basis. It was also found that the cultivation of P. ostreatus increased the crude protein content. while it decreased the ratio of lignin to cellul ose, of the spent grain substrate. (C) 2001 Elsevier Science Ltd. All right s reserved.