Effect of physico-chemical factors and semi-synthetic media on vegetative growth of Lentinus subnudus (Berk.), an edible mushroom from Nigeria

Attempts were made to investigate the effect of different semi-synthetic growth media, pH, temperature, carbon and nitrogen compounds, as well as additives, on vegetative growth of L. subnudus (Berk.), an edible mushroom from Nigeria. The best mycelial extensions (92.7 and 92. mm) were obtained on potato dextrose agar (PDA) and yellow corn agar (YCA), respectively. Moderate growths (87.0, 85.0 and 80.0 mm) were observed on white corn agar (WCA), yeast extract agar (YEA) and malt extract agar (MEA), respectively, but least growth (38.6 mm) was recorded on ‘Ife brown’ beans agar (IBBA). This fungus grew within a temperature range of 15–40 °C (optimum 30 °C) and, pH range of 5.0–8.0 (optimum 5.5).Among the 17 tested carbon compounds, the best growth (193.3 mg/30 cm3) was supported by fructose, followed in order by maltose, glucose and myo-inositol (P ⩽ 0.05). Twenty-one nitrogen sources were used and yeast extract enhanced the greatest mycelial dry weight (200.0 mg/30 cm3) while the least growth (33.0 mg/30 cm3) was obtained with l-glutamic acid. The most utilizable carbon/nitrogen ratio was 4:3, followed, in order, by ratios 5:3, 3:2 and 5:2 (P ⩽ 0.05), while the least growth was observed with the ratio 1:1. The additive that supported the best vegetative growth on Trema orientalis sawdust was 30% rice bran (98.0 mm). Moderate growth was also obtained with 1% fermented cow dung but very poor growth was observed with poultry manure. The implication of these findings in relation to the cultivation of L. subnudus in Nigeria is considered.