蜜环菌液体培养基碳氮源的筛选和优化

Screening and optimization of carbon and nitrogen sources in liquid medium of Armillaria mellea

【目的】筛选生长迅速、性状优良的蜜环菌菌株,对所选优良菌株的液体培养基进行碳氮源筛选和优化,为蜜环菌深层发酵技术的研究提供基础依据和参考。【方法】采用单因素试验,以生物量(菌丝体干质量)为指标,以工业发酵和生产中常用的菌株A9为对照,从本实验室分离与收集的20个蜜环菌菌株中筛选优良菌株,并设置不同的供试碳源、氮源、碳氮源组合、碳氮源含量,对其液体培养基的碳氮源进行筛选和优化。【结果】供试的20个蜜环菌中,菌株M41和M57生长迅速,生物量显著(P<0.05)高于对照菌株A9,其中M41菌索粗壮、性状优良,作为优良菌株用于后续研究。供试的7种碳源和5种氮源中,菌株M41和A9液体培养基的最佳碳源分别为玉米粉和麦麸,最佳氮源分别是菜籽饼和酵母浸粉,最佳碳氮源组合分别为玉米粉+菜籽饼、玉米粉+蚕蛹粉,最佳碳氮源含量分别为2%和4%。菌株M41和A9的最佳液体培养基为玉米粉2%、菜籽饼(M41)或蚕蛹粉(A9)4%、磷酸二氢钾0.15%、硫酸镁0.075%。恒温振荡(121 r/min,25℃)培养18 d后,菌株M41的菌丝体产量达16.71 g/L,显著高于对照菌株A9(10.76 g/L)(P<0.05)。【结论】筛选出的优良菌株M41可用于后续生产,优化液体培养基显著提高了蜜环菌菌株M41和A9的菌丝体产量。

【Objective】The Armillaria mellea strains with fast growth and excellent characteristics were screened,and the carbon and nitrogen sources were screened and optimized in the liquid medium of the selected strain,which provides basis and reference for the study of submerged fermentation technology of A.mellea.【Method】Using biomass(dry mass of mycelium)as the basis and the strain A9 commonly used in industrial fermentation and production as the control,single factor test was used to screen excellent strains from 20 A.mellea strains isolated and collected in the laboratory.The carbon and nitrogen sources of liquid medium were screened and optimized by setting different carbon sources,nitrogen sources,and their combinations with different contents.【Result】Among the 20 tested A.mellea,strains M41 and M57 grew rapidly,and their biomass were significantly higher than that of control A9(P<0.05).In addition,strain M41 had strong rhizomorph and excellent characteristics.Thus,it was used as the excellent strain for subsequent research.Among the seven carbon sources and five nitrogen sources tested,the best carbon sources of strains M41 and A9 in liquid medium were cornmeal and wheat bran,the best nitrogen sources were rapeseed cake and yeast extract powder,the best combination of carbon and nitrogen sources were cornmeal+rapeseed cake,cornmeal+silkworm pupa powder,and the best carbon and nitrogen contents were 2%and 4%,respectively.The optimum liquid medium for strains M41 and A9 were:2%cornmeal,4%rapeseed cake(M41)or silkworm pupa powder(A9),0.15%KH 2PO 4 and 0.075%MgSO 4.The mycelium yield of strain M41 reached 16.71 g/L 18 days after constant temperature oscillation(121 r/min,25℃),which was significantly higher than that of control strain A9(10.76 g/L)(P<0.05).【Conclusion】The selection of carbon and nitrogen sources had great impacts on the growth and yield of A.mellea,and the optimum carbon and nitrogen sources and the optimum medium composition of different A.mellea strains were different.The mycelial yields of A.mellea strains M41 and A9 were significantly increased by screening and optimizing carbon and nitrogen sources in liquid medium.The screened strain M41 could be used for subsequent production.