Biodetoxification fungus selectively degrades toxic inhibitors generated from pretreatment of lignocellulose without consuming fermentable sugars.However,one barrier for practical application is the sustained cell via...Biodetoxification fungus selectively degrades toxic inhibitors generated from pretreatment of lignocellulose without consuming fermentable sugars.However,one barrier for practical application is the sustained cell viability in the consequent fermentation step to compete the fermentable sugars with fermenting strains,resulting in sugar loss and reduced target product yield.This study investigated the competitive growth property between the biodetoxification fungus Paecilomyces variotii FN89 and the L-lactic acid bacterium Pediococcus acidilactici ZY271 under varying temperature and lactic acid osmatic stress.The results show that the L-lactic acid bacterium Ped.acidilactici ZY271 showed less thermotolerance to Pae.variotii FN89 at high temperature of 45°C to 50°C in both synthetic medium and wheat straw hydrolysate.In the higher temperature environment,the growth of the biodetoxification strian failed to compete with the lactic acid fermentation strain and was quickly eliminated from the fermentation system.The high temperature fermentation facilitated a fast transition from the detoxification stage to the fermentation stage for higher production of L-lactic acid.展开更多
[目的]以甲醛降解菌宛氏拟青霉菌F1-23为实验菌株,分离纯化得到甲醛脱氢酶的酶液,并考察其酶学性质。[方法]从液体培养液中收集菌体,通过细胞粉碎,采用(NH4)2SO4沉淀、透析、DFAE-Sepharose离子交换层析及Superdex-200凝胶过滤层析,纯...[目的]以甲醛降解菌宛氏拟青霉菌F1-23为实验菌株,分离纯化得到甲醛脱氢酶的酶液,并考察其酶学性质。[方法]从液体培养液中收集菌体,通过细胞粉碎,采用(NH4)2SO4沉淀、透析、DFAE-Sepharose离子交换层析及Superdex-200凝胶过滤层析,纯化得到电泳纯的FADH。[结果]该酶的分子量约为112.81 k Da;亚基分子量分别为65k Da和42 k Da;纯酶液活力为336.10 U/mg,较纯化前提高了4.02倍。对该酶的酶学性质分析结果表明,该酶最适反应温度为37℃,在25~45℃时稳定性很好;最适反应p H为8.0,在p H 6.5~8.0范围内酶活力较为稳定。底物特异性研究表明FADH最适底物为甲醛,相对偏好短链醛类。金属离子对酶活性的影响试验表明,Zn^(2+)、Mn^(2+)、Ag^+、Fe^(3+)和Hg^(2+)几乎完全抑制FADH酶活力;Ca^(2+)对酶活有促进作用。纯酶液在4℃环境下,在24h内可保存78%的活性。[结论]FADH结构较为特殊,且活性较大,为后期表达和深入研究其生物学功能提供理论和数据支持。展开更多
基金The National Key R&D Program of China(2023YFA0914400)the National Natural Science Foundation of China(32301269)+1 种基金China Postdoctoral Science Foundation(2023M741175)the Yangfan Project of Science and Technology Committee of Shanghai Municipality(23YF1409900).
文摘Biodetoxification fungus selectively degrades toxic inhibitors generated from pretreatment of lignocellulose without consuming fermentable sugars.However,one barrier for practical application is the sustained cell viability in the consequent fermentation step to compete the fermentable sugars with fermenting strains,resulting in sugar loss and reduced target product yield.This study investigated the competitive growth property between the biodetoxification fungus Paecilomyces variotii FN89 and the L-lactic acid bacterium Pediococcus acidilactici ZY271 under varying temperature and lactic acid osmatic stress.The results show that the L-lactic acid bacterium Ped.acidilactici ZY271 showed less thermotolerance to Pae.variotii FN89 at high temperature of 45°C to 50°C in both synthetic medium and wheat straw hydrolysate.In the higher temperature environment,the growth of the biodetoxification strian failed to compete with the lactic acid fermentation strain and was quickly eliminated from the fermentation system.The high temperature fermentation facilitated a fast transition from the detoxification stage to the fermentation stage for higher production of L-lactic acid.
文摘[目的]以甲醛降解菌宛氏拟青霉菌F1-23为实验菌株,分离纯化得到甲醛脱氢酶的酶液,并考察其酶学性质。[方法]从液体培养液中收集菌体,通过细胞粉碎,采用(NH4)2SO4沉淀、透析、DFAE-Sepharose离子交换层析及Superdex-200凝胶过滤层析,纯化得到电泳纯的FADH。[结果]该酶的分子量约为112.81 k Da;亚基分子量分别为65k Da和42 k Da;纯酶液活力为336.10 U/mg,较纯化前提高了4.02倍。对该酶的酶学性质分析结果表明,该酶最适反应温度为37℃,在25~45℃时稳定性很好;最适反应p H为8.0,在p H 6.5~8.0范围内酶活力较为稳定。底物特异性研究表明FADH最适底物为甲醛,相对偏好短链醛类。金属离子对酶活性的影响试验表明,Zn^(2+)、Mn^(2+)、Ag^+、Fe^(3+)和Hg^(2+)几乎完全抑制FADH酶活力;Ca^(2+)对酶活有促进作用。纯酶液在4℃环境下,在24h内可保存78%的活性。[结论]FADH结构较为特殊,且活性较大,为后期表达和深入研究其生物学功能提供理论和数据支持。
