产谷氨酰胺转胺酶菌株的筛选及其产酶条件研究

利用设计的低廉简便的凝胶法从土壤中分离得到1株高产谷氨酰胺转胺酶(microbialtransglutami-nase,MTG)的菌株,初步鉴定属于放线菌纲的链霉菌属(Streptomycessp.)。摇瓶发酵试验表明,其最适产酶氮源和碳源分别是蛋白胨和葡萄糖,通过正交试验确定最适产酶培养基为(g/L):葡萄糖20.0,蛋白胨20.0,酵母提取物3.0,MgSO4·7H2O2.0,K2HPO4·3H2O2.0,KH2PO42.0,CaCO35.0。单因素试验确定最佳培养时间和最适pH分别为72h和7.0;在优化条件下,发酵液中MTG酶活达1.04U/mL。     

漆斑菌发酵产胆红素氧化酶及其对酸性靛蓝脱色的研究

[目的]提高漆斑菌（Myrothecium sp.IMER1）产胆红素氧化酶产量,并研究其酶液对酸性靛蓝脱色性能。[方法]筛选合适的产酶培养基,研究外加碳源、温度、pH值等条件对产酶量的影响。提取粗酶液并对酸性靛蓝进行了脱色研究,用紫外-可见分光光度计扫描其在200~800 nm波长的变化。[结果]漆斑菌在PDB培养基上生长良好且产酶量最大;当以PDB培养基为基本培养基时,葡萄糖是其产酶的最适外加碳源,该菌最适产酶的温度和pH值分别是28℃和7.0。该酶在2 h内对酸性靛蓝脱色率可达到82%,酸性靛蓝降解液的扫描光谱图证实了染料分子的结构受到了破坏。[结论]试验结果为提高胆红素氧化酶产量提供了试验依据,证实了该酶在印染废水的脱色净化处理中具有潜在的应用前景。     

响应面法对漆斑菌液体发酵产胆红素氧化酶条件的优化

对漆斑菌(Myrothecium sp.IMER1)菌株液体发酵产胆红素氧化酶的条件进行了优化。采用单因素试验筛选出最适碳源为葡萄糖,氮源为硝酸铵,p H为7,温度为28℃和最有效促进产酶的金属离子为Cu2+。在此基础上,利用Plackett-Burman设计对影响产酶因素的效应进行评价,筛选出具有显著影响的3个因素葡萄糖、p H和温度。用最陡爬坡路径逼近最大产酶区域后,利用响应面中心组合设计对显著因素进行优化,得出p H、温度和葡萄糖分别为5.7、28℃、8 g/L时,优化后液体发酵液中胆红素氧化酶活力提高到0.627 U/m L,比未优化前的酶活力0.214 U/m L提高了近2倍,结果表明单因素与响应面结合法可优化菌株IMER1液体发酵产胆红素氧化酶的条件。     

蛋白质谷氨酰胺酶发酵条件的初步优化

蛋白质谷氨酰胺酶在食品行业中具有广泛的应用前景,通过对蛋白质的脱酰胺基作用,可以促进植物蛋白的溶解、乳化和起泡等。对产吲哚金黄杆菌产生蛋白质谷氨酰胺酶的代谢曲线和发酵培养基配方进行研究,结果表明,发酵液氨浓度和pH值随发酵时间延长而升高,发酵12 h酶活最高,发酵培养基初始pH值为5.2时酶活最高;通过单因素试验,确定乳糖和蔗糖为最适碳源,大豆蛋白胨和多聚蛋白胨为最适氮源;正交试验结果表明,大豆蛋白胨、乳糖和Tween 80最适浓度分别为1.2%、0.7%和0.15%,培养基优化后酶活最高为0.661 U/mL。     

β-甘露聚糖酶高产基因工程菌株发酵条件优化

采用正交试验对1株基因工程菌株的种子培养基与发酵培养基进行优化。通过在3因素（碳源、生长素、无机盐）3水平上进行正交试验,确定种子培养基成分为：0.5%牛肉膏,0.5%葡萄糖,0.5%蛋白胨,0.35%NaCl,0.1%KH2PO4,0.05%MgSO4;发酵培养基的成分为：0.5%牛肉膏,0.3%魔芋精粉,0.5%蛋白胨,0.35%NaCl,0.1%KH2PO4,0.05%MgSO4;产酶高峰时段为10～12 h之间,最适的发酵温度为35℃,最高酶活可达775 U/ml。     

红缘拟层孔菌的培养条件

为了解药用真菌红缘拟层孔菌的最佳培养条件,在单因素试验的基础上,以葡萄糖、蛋白胨、黄豆粉煮汁、pH值为因素,以菌丝干质量和发酵液抗肿瘤活性为标准,采用正交试验方法从中选出最优培养条件。结果表明:红缘拟层孔菌生长的最适温度为25℃,中性偏酸性环境,最适碳源为葡萄糖,氮源为蛋白胨,以菌丝干质量为标准,最优培养条件为:葡萄糖25 g/L,蛋白胨10 g/L,黄豆粉煮汁3 g/L,pH值为6;以发酵液抗肿瘤活性为标准,最佳培养条件为:葡萄糖20 g/L,蛋白胨8 g/L,黄豆粉煮汁4 g/L,pH值为6。     

红曲霉JR产红曲色素液态发酵培养基配方的筛选

首先对红曲霉JR产红曲色素的液态发酵培养基配方的筛选进行研究,结果表明葡萄糖、蛋白胨、硫酸镁、硫酸锌和硫酸锰最利于红曲色素的合成.在此基础上,应用二次正交旋转组合实验设计方法对发酵培养基选用的葡萄糖、蛋白胨、硫酸镁、硫酸锌和硫酸锰等组分作进一步研究,结果显示,红曲霉JR产红曲色素的较佳发酵培养基配方(g/L)为:葡萄糖33.18,蛋白胨13.36,MgSO_4 0.66,MnSO_4 0.1,ZnSO_4 0.1.该发酵培养基配方下红曲色素色阶达到203.4 U/mL,比二次正交旋转组合实验设计中的初始发酵培养基配方(葡萄糖50 g/L,蛋白胨10 g/L,MgSO_4 1.0 g/L,MnSO_4 0.1 g/L,ZnSO_4 0.1 g/L)下的红曲色素色阶(145.6 U/mL)提高将近39.70%.     

1株益生蜡样芽孢杆菌发酵培养基优化研究

[目的]通过优化蜡样芽孢杆菌的发酵培养基,提高蜡样芽孢杆菌的生物量。[方法]在初始发酵培养基的基础上,通过单因素试验和正交试验确定蜡样芽孢杆菌发酵培养基的最适碳氮源和碳氮比。[结果]优化后的发酵培养基为:葡萄糖15.00 g/L,可溶性淀粉40.00 g/L,蛋白胨10.00 g/L,玉米浆干粉30.00 g/L,硫酸铵3.00 g/L,磷酸氢二钾5.00 g/L,磷酸二氢钠5.00 g/L,硫酸镁1.25 g/L,硫酸锰0.60 g/L,氯化钙2.00 g/L。优化后蜡样芽孢杆菌在50 L不锈钢发酵罐中的发酵液活菌数达1.6×1010cfu/m L,较优化前提高了1个数量级。[结论]优化后的蜡样芽孢杆菌发酵培养基大大提高了该菌的生物量,为工业化放大生产提供了参考。     

一株黑曲霉产纤维素酶培养基优化

采用单因素试验和正交试验对黑曲霉FSDZH-1摇瓶发酵生产纤维素酶的营养条件进行优化。结果表明:其最佳培养基配方(g/L)为:玉米粉40.0,蛋白胨3.0,(NH_4)_2SO_42.0,Na_2HPO_40.5,Mg SO_40.2,Fe SO_4·7H_2O 0.1,CaCO_30.5。在最佳培养基条件下,发酵液酶活力可达315.6 U/m L。     

酿酒酵母发酵条件与培养基组成的优化研究

在单因素试验的基础上,进一步采用正交试验,对一株用于发酵饲料的酿酒酵母菌株进行了培养条件和培养基组成的优化试验。试验结果表明,该酿酒酵母菌株的最佳发酵条件为:接种量8%,培养基初始pH值6.5,转速250 r/min,发酵温度30℃,装液量20%,发酵时间30 h;最佳发酵培养基组成为:葡萄糖20 g/L,蛋白胨7.5 g/L,酵母粉7.5 g/L,磷酸二氢钾0.156 g/L,七水硫酸镁0.496 g/L。在上述发酵条件和发酵培养基下进行发酵,酿酒酵母活菌数可达8.4×108 CFU/mL。     

不同种植方式对苗期大豆、玉米根际土壤酶活性及微生物量碳、氮的影响

通过盆栽试验的方法,研究不同种植方式对苗期大豆、玉米根际土壤脲酶、过氧化氢酶、多酚氧化酶和蔗糖酶活性和微生物量碳、氮的影响,试验共设9个处理,分别在前茬作物为大豆、玉米和大豆-玉米混作的土壤上种植大豆、玉米和大豆-玉米混作。结果表明,①与大豆-玉米轮作相比,大豆连作降低了根际土壤多酚氧化酶和脲酶活性,玉米连作降低了脲酶活性而提高了过氧化氢酶活性,三种种植方式下蔗糖酶活性无显著差异。②与大豆-玉米混作相比,大豆连作和玉米连作都降低了根际土壤脲酶活性,提高了根际土壤蔗糖酶的活性,根际土壤多酚氧化酶的活性变化不明显。在前茬为玉米的土壤处理中,大豆-玉米混作的根际土壤过氧化氢酶活性显著低于单作大豆和单作玉米的处理。③大豆连作和玉米连作的土壤微生物量碳、氮均高于大豆-玉米轮作。在前茬为玉米的土壤处理中,大豆-玉米混作的土壤微生物量氮显著高于单作大豆和单作玉米的处理。④土壤微生物量碳与微生物量氮及其碳氮比都与土壤过氧化氢酶活性和多酚氧化酶活性呈显著相关或极显著相关。因此,不同的种植方式能够影响大豆和玉米的根际土壤酶活性和土壤微生物量碳、氮,但变化规律不尽相同。     

不同供氮水平对芸豆碳氮代谢平衡的影响

采用盆栽土壤基施0、15、30 kg·hm^-2三个氮 素水平试验，研究了芸豆荚果形成后不同氮素水平下叶片和荚果的碳、氮代谢主要酶活性 以及抗氧化酶系活性的变化。结果表明，芸豆荚果形成后，随着土壤供氮水平的增加，荚果 的磷酸烯醇式丙酮酸羧化酶活性、多酚氧化酶活性、超氧化物歧化酶和过氧化氢酶活性逐渐 增强；叶片的蔗糖合成酶活性、蔗糖磷酸合成酶活性、硝酸还原酶和磷酸烯醇式丙酮酸羧化 酶活性大于同一供氮水平荚果的活性；且荚果的总可溶性糖和可溶性蛋白含量高于叶片；叶 片的磷酸烯醇式丙酮酸羧化酶的活性与荚果的蔗糖磷酸合成酶和硝酸还原酶活性呈显著相关 性。由此可以得出，源器官是芸豆植株的代谢活跃中心，而库器官成为植株的生长中心，且 后者的碳、氮代谢过程主要受前者的调控。     

氮素和水分对贝加尔针茅草原土壤酶活性和微生物量碳氮的影响

在内蒙古贝加尔针茅草原,分别设对照(N0)、1.5 g·m^-2(N15)、3.0 g·m^-2(N30)、5.0 g·m^-2(N50)、10.0 g·m^-2(N100)、15.0 g·m^-2(N150)、20.0 g·m^-2(N200)和30g·m^-2(N300)(不包括大气沉降的氮量)8个氮素(NH₄NO₃)梯度和模拟夏季增加降水100 mm的水分添加交互试验,研究氮素和水分添加对草原土壤养分、酶活性及微生物量碳氮的影响。结果表明:氮素和水分添加对草原土壤理化性质和生物学特性有显著影响。随施氮量的增加土壤总有机碳、全氮、硝态氮、铵态氮含量呈增加的趋势,相反,土壤pH值呈降低的趋势。土壤脲酶和过氧化氢酶的活性随施氮量的增加而升高,多酚氧化酶则随施氮量的增加呈下降的趋势。氮素和水分添加对草原土壤微生物量碳氮含量有显著影响,高氮处理(N150、N200和N300)显著降低了微生物碳含量,微生物氮含量随施氮量的增加呈上升趋势。水分添加能够减缓氮素添加对微生物的抑制作用,提高微生物量碳、微生物量氮含量。草原土壤养分、土壤酶活性及土壤微生物量碳氮含量间关系密切,过氧化氢酶与全氮、总有机碳、硝态氮呈显著正相关,多酚氧化酶与铵态氮、硝态氮、全氮呈显著负相关。微生物量氮含量与土壤全氮、铵态氮、硝态氮含量以及过氧化氢酶和磷酸酶活性呈显著正相关,与多酚氧化酶呈负相关;微生物量碳与过氧化氢酶呈负相关,与多酚氧化酶活性呈正相关。     

Effects of Different Cropping Patterns of Soybean and Maize Seedlings on Soil Enzyme Activities and MBC and MBN

Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial bio...     

Changes in the activities of key enzymes and the abundance of functional genes involved in nitrogen transformation in rice rhizosphere soil under different aerated conditions

Soil microorganisms play important roles in nitrogen transformation.  The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods (continuous flooding (CF), continuous flooding and aeration (CFA), and alternate wetting and drying (AWD)).  The abundances of amoA ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering (S1), heading (S2), and ripening (S3) stages.  We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon (MBC) and soil microbial biomass nitrogen (MBN), with the concentration of soil nitrate and ammonium nitrogen.  The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments.  AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong.  During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively.  The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively.  The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase.  All the above indicators were positively correlated with soil MBC and MBN.  In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2.  Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.      

羟丙基壳聚糖对小麦幼苗生理功能的影响

利用0.3%羟丙基壳聚糖溶液对小麦幼苗进行喷洒处理,在幼苗发育的5个时段对4种酶活性和叶绿素含量进行测定。结果表明,用羟丙基壳聚糖处理后,硝酸还原酶、核酮糖二磷酸(RuBP)羧化酶、超氧化物歧化酶活性比对照高出20%左右,多酚氧化酶活性变化不显著,随着幼苗发育呈现先高后低的变化,叶绿素含量处理明显高于对照30%左右,说明羟丙基壳聚糖可以促进小麦碳氮代谢,对小麦的抗性和光合作用有明显的促进作用。     

Effects of Carbon and Nitrogen Additions on Soil Microbial Biomass Carbon and Enzyme Activities Under Rice Straw Returning

The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon, dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field, and the mechanism of the decomposition of rice straw returning to the field was discussed. Completely randomized experiment of the two factors of the three levels was designed, and a total of nine treatments of indoor soil incubation tests were conducted. Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source), 1(low levels of carbon and nitrogen sources) and 2(high levels of carbon and nitrogen sources), respectively. The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content. Compared with T0 N0, the microbial biomass carbon of T2 N2 was increased significantly by 170.48%; the dissolved organic carbon content of T1 N2 was significantly increased by 58.14% and the free humic acid carbon contents of T0 N2, T1 N1 and T2 N0 were significantly increased by 56.16% and 45.55% and 47.80%, respectively; however, there were no significant differences among those of treatments at later incubation periods. The addition of different carbon and nitrogen sources could promote the soil enzyme activities. During the incubation period, all of the soil enzyme activities of adding sugar and urea were higher than those of T0 N0 treatment. Therefore, the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content, dissolved organic carbon and soil enzyme activities.     

氮肥施用对柑橘果园土壤有机碳矿化的影响(英文)

[目的]了解柑橘果园土壤有机碳矿化在不同温度下对不同氮肥施用量的影响关系,为构建果园生态系统的碳循环模型提供参数。[方法]采用室内模拟试验,在10、20、30℃3个温度条件下,研究施肥施用对柑橘果园土壤有机碳矿化的影响。[结果]3种温度处理下,各施氮处理土壤有机碳矿化速率都表现为培养前期快速下降,培养后期保持相对稳定的趋势。在整个培养过程中,3种温度条件下各施氮处理的土壤CO2累积排放量为1328.25~2219.42mg/kg,100mg/kg(N4)处理土壤有机碳矿化量最大,CK处理最低,100mg/kg(N4)和80mg/kg(N3)2个高氮处理显著高于低氮50mg/kg(N2)、30mg/kg(N1)处理。土壤有机碳矿化速率随温度升高而增长,不同的土壤施氮条件下土壤有机碳矿化的温度敏感性不同,N2处理土壤有机碳矿化的温度敏感性最低,N4处理最高。柑橘果园土壤有机碳矿化受高施氮量影响较大,低施氮影响不明显。[结论]随着施氮量的增加土壤有机碳矿化的温度敏感性增加,氮肥施用和温度的共同作用可能使柑橘林向大气中排放的CO2增加。     

不同施肥处理对红壤水稻土团聚体有机碳、 氮分布和微生物生物量的影响

【目的】研究不同施肥处理对红壤水稻土水稳性团聚体组成、不同粒级团聚体中有机碳、氮含量与分布及土壤微生物生物量碳氮含量的影响,为揭示施肥对土壤肥力形成演变的影响机制提供重要理论依据。【方法】依托鹰潭农田生态系统国家野外科学观测研究站已进行了20年的长期定位试验,试验包括9个处理：对照（不施肥,CK）、有机质循环（C）、化学氮肥（N）、氮肥+有机质循环（NC）、化学氮磷肥（NP）、化学氮磷钾肥（NPK）、化学氮磷钾肥+有机质循环（NPKC）、化学氮磷肥（NK）和化学氮磷钾肥+1/2秸秆回田（NPKS）。采集各小区耕层土壤,利用湿筛法得到不同粒级水稳性团聚体,测定团聚体中有机碳、氮含量及土壤微生物量碳、氮含量。【结果】长期不同施肥处理对＞2 mm团聚体含量影响最大,与对照相比,施用有机肥的处理（NC、NPKC、C）该粒级团聚体含量分别提高了37.0%、22.6%和33.2%。各施肥处理下,有机碳、氮在1—2 mm团聚体中含量最高,在0.053—0.25 mm团聚体中含量最低,＞0.25 mm大团聚体比＜0.25 mm微团聚体含有更多的有机碳、氮。有机肥的施用显著提高了各粒级团聚体中有机碳、氮的含量,NC处理各粒级团聚体中有机碳、氮含量均最高,与对照相比,各粒级有机碳提高了17.0%—34.6%,全氮提高了25.8%—48.3%。0.25—1 mm和＞2 mm粒级团聚体对全土有机碳和全氮的贡献率最大,前者贡献率分别为22.1%—30.3%和23.3%—33.7%,后者贡献率分别为24.7%—37.3%和25.5%—38.0%。不同施肥处理间土壤微生物量碳、氮含量也有显著差异,与对照相比, NC、NPKC和C处理微生物量碳提高了122.1%、127.0%、94.0%,微生物量氮提高了92.0%、43.1%、91.1%。＞2 mm团聚体含量与全土有机碳、全氮、微生物量碳、微生物量氮含量及水稻产量呈显著或极显著正相关,＜0.053 mm团聚体则与之呈显著或极显著负相关。【结论】水稳性大团聚体是土壤有机碳、氮的主要载体;有机肥的施用显著提高了水稳性大团聚体及其中有机碳、氮的含量,是改善土壤团粒结构,提高红壤生物功能和生产力的有效措施。     

福州地区7年生柑橘果园生态系统的碳氮储量

通过野外实地调查对福州地区林龄7年的柑橘果园生态系统碳氮储量及分布特点进行了研究,结果表明:有机碳储量为158.282 t.hm-2,其中土壤(0-100 cm)碳储量为151.734 t.hm-2,占总有机碳储量的95.86%,植被碳储量为6.548 t.hm-2,占4.14%;氮储量为14.602 t.hm-2,其中土壤(0-100 cm)氮储量为14.399 t.hm-2,占总氮储量的98.61%,植被氮储量为0.203 t.hm-2,占1.39%.相关分析表明,柑橘果树不同器官碳氮含量呈极显著负相关(r=0.976),不同土层土壤的碳氮含量呈极显著正相关(r=0.998).