Sensitivity of mycelial growth of mushroom Agrocybe semiorbicularis to different concentrations of different disinfectants

Abstract

This study was performed to determine the effects of different types of disinfectants (Hypo, Izal, and Dettol) on the mycelial growth of the mushroom Agrocybe semiorbicularis. The more evolutionarily advanced mushroom mycelium was expected to show greater resistance to disinfectants than other fungal and bacterial contaminants. Minimal disinfectant concentration was the one at which contaminants were inhibited, while the growth of the desired mushroom mycelia remained unaffected. Different concentrations of different disinfectants were added to the growth media, and the pure mushroom mycelial culture was inoculated on the media and left to grow. The results revealed that the probability of contamination was higher in all the concentrations of Hypo and in lower concentrations of Dettol and Izal. At 5% concentration of the disinfectants (Hypo, Izal, and Dettol), the mean values of contamination were 0.667, 0.417, and 0.00 (P < 0.001), respectively. At 10% concentration, the mean contamination values were 0.167, 0.583, and 0.333 (P > 0.05), respectively, while at 15% concentration, the mean contamination values were 1.000, 0.417, and 0.250 (P < 0.05), respectively. At higher concentrations of the disinfectants, the growth of contaminants was completely suppressed, and the growth of the desired mycelia was also significantly decreased. At 17% concentration of the disinfectants (Hypo, Izal, and Dettol), the mean values of contamination were 0.833, 0.833, and 0.00 (P < 0.05), respectively. At 18% disinfectant concentration, the mean contamination values were 0.167, 0.00, and 0.00 (P > 0.05), respectively, while at 20% disinfectant concentration, the mean contamination values were 0.583, 0.00, and 0.00(P < 0.05), respectively. The mean values of the mushroom’s mycelial growth for the three disinfectants (Hypo, Izal, and Dettol) were 6.26, 15.38, and 21.93 mm (P < 0.05), respectively, for 5% concentration; 11.75, 10.08, and 13.90 mm (P > 0.05), respectively, for 10% concentration; and 0.00, 12.88, and 18.33 mm (P < 0.05), respectively, for 15% concentration. At higher concentrations of the disinfectants (Hypo, Izal, and Dettol), the mean values of the mushroom’s mycelial growth were 16.92, 11.90, and 14.33 mm (P > 0.05), respectively, for 17% concentration; 18.54, 3.00, and 8.71 mm (P > 0.05), respectively, for 18% concentration; and 13.50, 13.25, and 0.00 mm (P > 0.05), respectively, for 20% concentration. Disinfectants that yielded 100% (12/12) growth of pure cultures were 18% and 20% concentrations of Izal and 15% concentration of Dettol (P < 0.05). Dettol at concentrations of 10%, 17%, and 18% yielded 66.7% (8/12) of pure cultures, but with a significant decrease in growth (P < 0.05) and viability; moreover, no contaminants survived at these concentrations. In general, mushroom mycelia were found to exhibit a higher degree of resistance to disinfectants than fungal and bacterial contaminants. Pure mycelial cultures were obtained in almost all the concentrations of all the disinfectants, but there were trade-offs between the levels of contaminations and better growth of the desired mycelia. Dettol was found to have the highest effect on suppressing contaminant growth followed by Izal and the least effective was Hypo. The result of this study will help in the process of mushroom production by reducing the problems of contamination.