Anti-Growth Factors Associated with Pleurotus ostreatus in a Submerged Liquid Fermentation

Aims: Previous studies had revealed that cultivation of Pleurotus ostreatus is often met with a lot of challenges ranging from environmental to biological factors which adversely affect the successful cultivation of the mushroom. Hence, a need to determine factors against mycelia colonization of substrate during mushroom’s cultivation.Methodology and Result: Conventional streak method was employed to establish the percentage inhibition as well as intercolony distance between the test organisms obtained from the infected substrate and mycelia of the mushroom during substrate colonization. The test organisms are: a fungus, Kutilakesopsis macalpineae and a bacterium,Pseudomonas tolaasii. The effect of pH and temperature on the mycelia growth of P. ostreatus was also investigated. There was a gradual increase in the percentage inhibition from 33.3 % at 24 h to 75.0 % at 168 h for K. macalpineae and 37.5 % at 24 h to 70.0 at 168 h for P. tolaasii. The inter-colony distance between the antagonists and the mushroom mycelium gradually decreased. Optical density of the mycelium growth was at its optimum at pH 4.5 and temperature of25 °C respectively. In vitro study also showed a significant increase in the optical density from 0.855±0.03 at 24 h to 1.316±0.02 at 168 h in the absence of test antagonist as against 0.812±0.06 and 0.79±0.02 at 24 h to 1.103±0.03 and 0.902±0.03 at 168 h when K. macalpineae and P.tolaasii were used as test antagonistic respectively.Conclusion, significance and impact of study: Sterilization of substrate is essential to avoid contamination during mycelia colonization. Also, slightly acidic medium and temperature control is necessary for high yield of fruit bodies.