白洋淀水中白腐真菌对双酚A的降解规律及途径研究

研究白洋淀表层水(白洋淀原水)、无机盐培养基、无机盐培养基强化的白洋淀原水中双酚A在白腐真菌作用下的生物降解规律,同时考察了细菌及pH等因素对降解率的影响.实验结果表明,白洋淀原水中双酚A在白腐真菌作用下的降解率很高.甚至高于最适营养条件(无机盐培养基)下双酚A的降解率.在6 d达到完全降解.但是无机盐培养基强化的白洋淀原水抑制了白腐真菌对双酚A的降解;当细菌存在时.白腐真菌与细菌对碳源和能源等形成了竞争关系,抑制了白腐真菌的生长.不利于白腐真菌对双酚A的降解;无机盐培养基强化的白洋淀原水在初始pH-6.00时双酚A的降解率高于初始pH=7.00时双酚A的降解率.通过气相色谱/质谱(GC/MS)分析.白腐真菌降解双酚A的中间产物包括2-对羟苯基-2-酮基-1-乙醇、2-羟基苯乙酸和丙二酸等小分子酸.     

菌根在污染土壤生物修复中的作用

菌根是土壤真菌 -植物根系形成的共生体 ,广泛存在于自然界中 ,它能增强植物的吸收能力 ,改善植物的生长 ,提高植株的抗逆能力和耐受能力等。所以 ,菌根化植物可作为很好的生物修复载体。本文主要从无机、有机以及放射性污染 3方面对国内外关于菌根在污染土壤生物修复中的作用进行了综述     

8种中药提取物对植物病原真菌的抑制活性

研究目的是改良植物源杀菌剂的筛选思路,降低植物源农药的毒残留,寻找效果较持久的植物源杀菌剂.通过筛选提取常见且具有强抗逆性的植株如柳、盐肤木等植物叶中活性抑菌成分,寻找低毒持效的杀菌剂.从试验数据分析得出,在粗提物质量浓度为50mg/mL时,连翘、盐肤木对3种供试植物病原菌抑制效果显著,抑制率均在65%以上,柳叶、马尾松针、臭椿、茵陈蒿的粗提物对至少两种植物病原菌的菌丝生长速率抑制率在50%以上;香槐和枫杨叶活性较低,仅对其中一种病原菌活性达到50%;柳叶、马尾松针、臭椿叶对两种病原菌气生菌丝的生长状况具有明显的抑制作用;盐肤木粗提物的抑制作用具有较好的延续性,因此连翘、盐肤木作为植物源杀菌剂具有深入研究的价值.     

食用植物油油脚的资源化利用新途径

食用植物油油脚是植物油毛油精炼过程中的尉产品,来源广、数量大且价格低廉,目前还没找到很好的利用方法.为了资源化利用油脚,对其成分进行了测试.结果表明,油脚包含了有机质、蛋白质、氨基酸、糖脂、磷、钾等许多益于食用菌生长的营养成分,且不存在重金属污染问题,可替代部分价格较高的棉籽壳、麦麸等传统食用菌原材料.     

重金属污染土壤的生物修复——菌根技术的应用

本文阐述了重金属污染土壤的修复现状,提出菌根修复技术做为土壤重金属污染生物修复技术是目前研究的热点。主要从其作用原理和已有研究成果分析菌根技术的优越性,并提出不足和发展展望。     

丛枝菌根强化型生态浮床处理煤化工模拟含盐废水

针对缺乏经济有效的中低盐废水脱盐技术问题,本试验利用丛枝菌根(AM)真菌增强植物抗盐胁迫能力,搭建AM强化型生态浮床,既探索新的中低盐废水处理技术,又解决普通浮床植物耐盐胁迫能力差、除盐效率低的问题.结果表明,AM真菌(Glomus etunicatum)与浮床植物美人蕉(Canna indica L.)建立了良好的共生关系,且侵染不受盐胁迫的影响.接种AM真菌提高了生态浮床处理含盐废水的能力,21 d内TDS、COD、TN和TP的去除率分别达到了36. 1%、74. 4%、57. 6%和59. 1%,比未接种AM真菌的普通生态浮床分别提高了79. 2%、36. 4%、32. 7%和37. 6%.从具体盐离子来看,21 d内水体中Na、K、Ca和Mg离子的去除率分别达到了34. 4%、61. 3%、57. 4%和51. 9%,相比未接种AM真菌的普通生态浮床分别提高了11. 4%、37. 1%、18. 3%和24. 6%.从植物对盐的吸收来看,AM的存在促进了美人蕉对Na离子的吸收和向地上部的转移,这可能是AM强化型生态浮床功能得到提升的主要原因之一.本研究表明AM真菌可增强生态浮床修复水体污染的能力,提高脱盐效率.     

The formation kinetics and control of biofilms by three dominant fungi species isolated from groundwater

Filamentous fungi can enter drinking water supply systems in various ways, and exist in suspended or sessile states which threatens the health of individuals by posing a high risk of invasive infections. In this study, the biofilms formation kinetics of the three genera of fungal spores, Aspergillus niger (A. niger), Penicillium polonicum (P. polonicum) and Trichoderma harzianum (T. harzianum) isolated from the groundwater were reported, as well as the effects of water quality parameters were evaluated. In addition, the efficiency of low- concentrations of chlorine-based disinfectants (chlorine, chlorine dioxide and chloramine) on controlling the formation of fungal biofilms was assessed. The results showed that the biofilms formation of the three genera of fungi could be divided into the following four phases: induction, exponential, stationary and sloughing off. The optimum conditions for fungal biofilms formation were found to be neutral or weakly acidic at 28 °C with rich nutrition. In fact, A. niger, P. polonicum, and T. harzianum were not observed to form mature biofilms in actual groundwater within 120 hr. Carbon was found to have the maximum effect on the fungal biofilms formation in actual groundwater, followed by nitrogen and phosphorus. The resistance of fungal species to disinfectants during the formation of biofilms decreased in the order: A. niger > T. harzianum > P. polonicum. Chlorine dioxide was observed to control the biofilms formation with maximum efficiency, followed by chlorine and chloramine. Consequently, the results of this study will provide a beneficial understanding for the formation and control of fungal biofilms.     

锰过氧化物酶(MnP)对农药毒死蜱降解的初步研究

以广泛使用的有机磷杀虫剂毒死蜱为研究对象,利用白腐菌P.sordida YK-624菌株所产锰过氧化物酶(MnP)对其进行生物降解的初步研究。首先比较确定了MnP降解毒死蜱所需要的降解体系,即对于毒死蜱的降解,需要在有机酸(丙二酸)存在的缓冲体系中进行,此体系不需要表面活性剂Tween 80,但必须含有Mn2+和葡萄糖氧化酶氧化葡萄糖产生的H2O2。随后对主要影响因素的试验结果表明,MnP降解毒死蜱较好的条件是在pH 4.5的丙二酸缓冲体系中含7.5 mmol/L MnSO4、2.5 mmol/L葡萄糖以及40 U葡萄糖氧化酶,温度30℃。此时,400 U/L的MnP可将30 mg/L的毒死蜱经3 d时间降解77.51%。同时,利用GC-MS对毒死蜱酶降解后的产物进行了初步分析,得到1种可能的酶解产物O,O,O’,O’-四乙基二硫代焦磷酸酯,不同于水解和细菌降解途径,值得进行进一步研究。     

白腐真菌吸附废水中Zn~(2+)的影响因素及吸附机理研究

研究白腐真菌粉末对Zn2+的吸附效果、影响因素及其吸附机理。结果表明,35 min后吸附过程基本完成,pH适宜范围为5~6,Zn2+吸附率随着Zn2+初始浓度增大而提高,且在Zn2+初始浓度为25 mg/L,吸附剂用量为2.5 g/L,pH为5.5的最佳条件下,Zn2+吸附率达到98.01%。与原白腐真菌相比,用0.8 mol/L NaOH对菌样进行预处理,Zn2+的吸附率可提高10%左右。运用扫描电镜(SEM)、X射线衍射仪(XRD)和红外光谱仪(FTIR)对Zn2+吸附前后的白腐真菌粉末进行表征。结果表明,白腐真菌表面粗糙,孔隙多。吸附Zn2+的过程中,白腐真菌表面的-OH和-PO4与Zn2+发生络合反应,生成的产物主要为磷酸锌和氢氧化锌。     

Antifungal efficacy of some natural phenolic compounds against significant pathogenic and toxinogenic filamentous fungi

In terms of food safety, species of the Fusarium, Aspergillus and Penicillium genera are considered the most significant because they produce the great majority of known mycotoxins. Developing resistance against commonly used fungicides have become a critical problem in area such as agriculture, the storage and production of food and even in human medicines. The need for research and development of new alternative antifungal treatment based on natural antifungal substances is obvious. Here, the antifungal efficacy of 21 phenolic components of essential oils and plant substances were tested against these filamentous fungi with respect to their different molecular structures. Minimum inhibitory concentration values MIC₅₀ and MIC₁₀₀ were successfully estimated for 15 substances by means of probit analysis. Thymol and carvacrol were evaluated as the most effective. The MIC₅₀ values for thymol ranged from 30 to 52 μg mL⁻¹. The MIC₁₀₀ values for thymol ranged from 76 to 255 μg mL⁻¹, respectively. For carvacrol, the MIC₅₀ values ranged from 37 to 76 μg mL⁻¹, and the MIC₁₀₀ ranged from 131 to 262 μg mL⁻¹. The results also revealed differences in the efficacy of phenols depending on molecular structures and different inter-species sensitivity.