| Pleurotus eryngii,also known as king trumpet mushroom,is one of the most important factory cultivation varieties of edible fungi in China.However,current information regarding the effect of environmental conditions on the growth and development of P.eryngii is very rare,which is possibly associated with such practical problems encountered in P.eryngii cultivation as the high production cost,low production efficiency,and so on.In this study,a Bacillus spp.(named Bacl)was isolated and purified from the environment and the effects of the Bac1 fermentation broth on mycelium growth and fruit body formation of P.eryngii were analyzed.The main findings are as follows:1.The effect of Bacl fermentation broth on mycelium growth of P.eryngiiAssays for mycelium grown on solid medium showed that medium supplemented with 5 mL Bacl fermentation broth exerted a positive effect on the mycelium growth of P.eryngii.When mycelium treated by Bacl fermentation broth,the mycelium growth rate and mycelium diameters were 5.49 mm/d and 6.91 μm,respectively,which were 13.33%and 26%higher than those in the control treatments.Assays for mycelium grown in liquid medium showed that when mycelium grew in medium supplemented with 5 mL Bacl fermentation broth before and after medium sterilization,the dry weight of the mycelium was significantly increased and found to be 4.5 g/L and 4.8 g/L,respectively,which were 1.60-fold and 1.71-fold higher than those in the control treatments;both the enzymatic activities of laccase and amylase were greatly increased and the max enzymatic activities of laccase were found to be 137.77 U/mL and 144.16 U/mL,respectively,which were 23.37%and 29.09%higher than those in the control treatments,while the max enzymatic activities of amylase were found to be 33.43 U/mL and 38.16 U/mL,respectively,which were 25.53%and 43.83%higher than those in control treatments.Taken together,the above results demonstrated that the Bacl fermentation broth could significantly increase two extracellular enzymatic activities of P.eryngii and promote the growth of mycelium.2.The effect of Bacl fermentation broth on the formation of P.eryngii fruit bodyAssays for P.eryngii fruit body formation showed that when P.eryngii cultivated in substrate supplemented with 10 mL Bac1 fermentation broth before sterilization,6 mL Bacl fermentation broth at inoculation,8 mL Bac1 fermentation broth at the phase of the mycelium growing to 1/2 position of the cultivation bottle,and 8 mL Bacl fermentation broth at the phase of the mycelium growing to full cultivation bottle,the fruit body growth was significantly promoted and the fresh fruit body weight was found to be 39.51 g,33.42 g,40.58 g,and 35.61 g,respectively,which were 1.29-fold,1.10-fold,1.32-fold,and 1.16-fold higher than those in the control treatments;the biological efficiency was 78.86%,66.84%,81.22%,and 71.50%,respectively;the bulk density was 0.74 g/mL,0.65 g/mL,0.75 g/mL,and 0.70 g/mL,respectively;the growth cycle of fruit body were shortened by 4 days,2 days,5 days,and 2 days,respectively,when compared to the control treatments.The above results demonstrated that the Bac1 fermentation broth could exert a positive effect on the growth of P.eryngii fruit body.3.The effect of Bacl fermentation broth on extracellular enzyme activity of P.eryngiiAssays for extracellular enzyme activities during the development of P.eryngii showed that when P.eryngii cultivated in substrate supplemented with 10 mL Bac1 fermentation broth before sterilization,6 mL Bac1 fermentation broth at inoculation,8 mL Bac 1 fermentation broth at the phase of the mycelium growing to 1/2 position of the cultivation bottle,and 8 mL Bac1 fermentation broth at the phase of the mycelium growing to full cultivation bottle,the highest enzymatic activities of laccase were found in the phase of primordium stage and the values were 86.94 U/mL,80.00 U/mL,90.55 U/mL,and 80.27 U/mL,respectively,which were 27.75%,17.07%,30.92%,and 17.79%higher than those in the control group;the highest enzymatic activities of amylase were also found in the phase of primordium stage,and the values were 99.55 U/mL,95.65 U/mL,105.20 U/mL,and 112.76 U/mL,respectively,which were 14.66%,8.69%,20.28%,and 25.02%higher than those in the control group;however,the highest enzymatic activities of carboxymethylcellulase were found in the mature fruit body phase,and the values were 329.82 U/mL,317.98 U/mL,339.28 U/mL,and 320.91 U/mL,respectively,which were increased by 17.78%,12.88%,18.45%,15.81%when compared to the control group.The above results demonstrated that Bacl fermentation broth could significantly increase three extracellular enzymatic activities of P.eryngii.In this study,the effect of Bacl fermentation broth treatment on the mycelium growth and fruit body formation of P.eryngii were systematically analyzed.And the corresponding results clearly demonstrated that the Bacl fermentation broth could promote mycelium growth,fiuit body growth,and extracellular enzyme secretion of P.eryngii.Our results will not only provide an important theoretical basis for reducing the production cost,increasing production efficiency,and innovating the cultivation model ofP eryngii,but also possess significant application values for promoting product exploitation,shortening the growth cycle,and reducing the production cost of P.eryngii. |
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