Biological Characteristics And Fermentation Technology Optimization Of Beauveria Bassiana Strain JG-17

In order to provide theoretical basis for large-scale industrialized production of the newly discovered strain JG-17,we optimize its liquid-phase fermentation and solid-state fermentation conditions by using liquid-solid two-phase fermentation culture method.The main conclusions are as follows:The strain of JG-17 belongs to Deuteromycotina,Hyphomycetes,Moniliales,Moniliaceae,Beauveria bassiana in fungal taxonomy.JG-17 colony on PDA medium is white velvety at the early stage and powdery at the later stage.Conidia are oval,smooth and transparent,with a size of about1.6².0μm×2.7⁴.2μm.JG-17 can achieve the best growing development at（27±2）℃,but do not germinate when the temperature was above 35℃.The results indicated that high temperature would inhibit the normal growth of strain JG-17.The liquid-phase fermentation of strain JG-17 were screened by single factor analysis method.It was found that the initial quantity in 1×10⁵¹×10⁷ mL^-1（F=108.000,P<0.01）,culture temperature within the range of 25 to 33℃（F=80.177,P<0.01）and train speed in 100²00 r·min^-1（F=68.182,P<0.05）is significant difference to the liquid culture of strain JG-17.But there was less significant difference in liquid-phase fermentation between the liquid loading amount of 30¹50mL（F=5.671,P>0.05）and the initial pH of 5.5⁷.5（F=2.632,P>0.05）.Through orthogonal experiment design of initial inoculation quantity,rotational speed and temperature,the results showed that the biomass of strain JG-17 was increased 124.24%than before under the conditions of initial inoculation concentration of 1×10⁷mL^-1,rotational speed of 180 r·min^-1 and the temperature of 25℃.Single factor experiment was used to screen carbon and nitrogen source nutrients and inorganic salts that suitable for the growth of strain JG-17.Response surface method was used to optimize the medium that suitable for the growth of strain JG-17.The result showed that:corn meal 40g·L^-1,fish meal 15g·L^-1,ZnSo₄ 0.15g·L^-1,MgSo₄ 0.30g·L^-1,28.6℃,the growth rate of strain JG-17 was（4.30±0.02）mm·d^-1,the sporulation reached（3.19±0.13）×10⁸cm^-2.The spore content was 165.83%higher than before.