生防菌哈茨木霉FJAT-9040深层发酵的生长适合度分析

摘要

为了解哈茨木霉 Trichoderma harzianum菌株FJAT-9040在液体深层发酵培养过程中pH值、孢子数等参数及抑菌作用的动态变化，采用50 L全自动发酵罐对菌株FJA T-9040进行液体发酵培养，检测不同发酵时段培养液的pH值、黏度、孢子数和菌丝干重等参数，分析各参数间的相关性，并探讨不同发酵时段的培养液和无菌上清液对枯萎病菌菌株FJAT-135的抑制作用。结果表明，在菌株FJAT-9040的发酵过程中，培养液pH值呈先降低、32 h后缓慢上升的变化，变化幅度较小；黏度值呈波浪式上升，末期下降；孢子数的变化表现为前期下降、中期增长、后期基本稳定，最大时达1.4×107 cfu·mL -1；菌丝干重则呈现阶梯式增长，至发酵结束时达10.29 mg · mL -1。发酵过程中，培养液的 pH值与黏度的相关性不显著，但与孢子数和菌丝干重极显著相关；黏度也与孢子数、菌丝干重极显著相关；孢子数与菌丝干重也呈极显著相关。液体发酵的最适时间为96～108 h。各发酵时段的菌株FJA T-9040培养液对菌株FJA T-135都具有较强的抑制作用，抑制率达77.92％以上；菌株FJA T-9040无菌上清液则未表现出抑菌作用。%Effect of medium pH ,spore number and other factors on the submerged fermentation of the FJAT-9040 strain of T richoderma harz ianum and the inhibition activities of the resultant fermentation liquid and sterile supernatant on the strain FJAT-135 of Fusarium oxysporum were investigated .The submerged fermentation was carried out in a 50L automatic fermentation vessel .Fermentation duration ,pH ,viscosity ,spore count and dry mycelia weight were altered to study their correlations .The results showed that ,during the fermentation ,(a) the pH decreased initially but slowly increased after 32 hours ;(b) the viscosity showed an increase-decrease-increase trend and followed by a decline toward the end ;(c) the spore count decreased firstly ,increased at the mid-stage , and remained constant at the end ;and (d) the dry mycelia weight increased stepwise to reach 10.29 mg · mL -1 at the end .Except between pH and viscosity ,there were significant correlations between pH and spore count ,between pH and dry mycelia weight ,between viscosity and spore count ,between viscosity and dry mycelia weight ,as well as between spore count and dry mycelia weight .The optimum duration for the fermentation was 96 -108 hours .At different culture stages ,all fermentation products were effective in inhibiting the growth of FJAT-135 at a rate above 77.92% .On the other hand ,the sterile supernatant of the fermentation liquid was not found to have the inhibiting effect .The results obtained from this study provide the basic information for the development of a cost-effective submerged fermentation process of FJAT-9040.