一个产氢产乙酸菌互营共培养体的培养基优化

Composition optimization of medium for a syntrophic acetogen coculture

摘要:

营养生态位位于产酸发酵菌和产甲烷菌之间的产氢产乙酸菌,其分离培养困难,种子资源匮乏,限制了基于强化产氢产乙酸功能作用的高效厌氧生物处理技术的开发.在前期获得对丙酸具有较强降解能力的产氢产乙酸菌互营共培养体7-m-2a的基础上,探讨了丙酸质量浓度、氮源、Ca2+、Fe2+、Mg2+和泛酸等对其生长代谢的影响.结果表明,培养基中适宜的丙酸钠和Fe2+、Mg2+、泛酸质量浓度分别为10 g/L和88、38、30 mg/L,最佳氮源是由质量浓度为0.33 g/L的酵母膏、胰蛋白胨和NH4Cl组成的复合氮源.在优化条件下38℃培养30 d,7-m-2a对丙酸的降解速率和乙酸产量分别可达998 mg/(L.d)和3 947 mg/L.

Abstract:

Hydrogen-producing acetogens,between acidogenes and methanogens in trophic niche,is very difficult to be separated and only few of the pure cultures have been obtained.This has restricted the development of new anaerobic organic wastewater treatment process with high efficiency based on enhancing their metabolic capability.A new syntrophic acetogen coculture named 7-m-2a which showed great capacity in degrading propionic acid was introduced in this paper.To optimize the culture medium,the influences on 7-m-2a’s growth and metabolism of propionic acid concentration,nitrogen sources,Fe2+,Mg2+,Ca2+ and pantothenic acid were investigated.The results indicated that the suitable concentration of propionic acid and Fe2+,Mg2+,pantothenic acid were 10 g/L and 88,38,30 mg/L,respectively.The optimum nitrogen source was the mixture of yeast extract,tryptone and NH4Cl with a concentration of 0.33 g/L respectively.With the optimization culture,a specific degradation rate of propionic acid and acetic acid yield of 998 mg/(L·d) and 3 947 mg/L,respectively,obtained after fermenting for 30 days at 38 ℃.