玫瑰色微球菌的生物学特性及其培养基的优化

对本实验室分离纯化的玫瑰色微球菌（Micrococcus roseus）M1进行生物学特性研究,包括形态与培养特征的观察,细胞色素的测定,菌体对碳氮源和生长因子的利用,以及该菌株的最适生长条件。通过单因素试验,获得菌株最适生长条件为：培养温度30℃、p H7.5、振荡频率120 r/min、盐度0.5%。采用均匀设计法优化菌株M1的培养基,得到最优培养基（g.L-1）：CH3COONa 6;NH4Cl 2.4;Na HCO30.1;Mg SO40.1;维生素溶液12 m L/L;微量元素溶液1 m L/L。在最适生长条件下,接种菌株M1于最优培养基,培养72 h后,菌体和类胡萝卜素的OD值分别达到2.753和4.733,而在基础培养基上的生物量和类胡萝卜素的OD值为1.895和3.258,分别提高了45%和50%。     

脱氮菌株的诱变育种及其脱氮条件的优化

以一株具有脱氮功能的玫瑰色微球菌(Micrococcus roseus)为出发菌株,经紫外线(UV)、硫酸二乙酯(DES)、氯化锂(LiCl)诱变剂反复诱变处理,并通过纳氏试剂法初筛和氨氮滴定法复筛,得到一株脱氮能力较强的菌株Mc32,脱氮率比出发菌株提高了36.8 %.采用正交设计实验优化Mc32菌株的脱氮条件,优化后的菌株脱氮率达到74 %,多次传代实验表明该菌株遗传稳定性较好.     

一株脱氮硫杆菌的筛选及其脱氮除硫性能分析

利用人工模拟酸性环境,从定期浇注HCl的土壤中筛选出一株脱氮硫杆菌T1菌株,并对其生长特性以及pH、盐度等理化因素对其脱氮除硫性能的影响进行了研究。结果表明,该菌株最适生长pH为7.02,最适脱氮pH为7.0;培养基中NaCl含量低于1.5%时,其脱氮能力没明显变化;与硫酸盐还原菌混菌培养能将H2S氧化为SO42-,从而明显抑制H2S的产生。在液体静置混菌培养过程中,在培养开始后的24 h内,SO42-生成速率最大(11.21 mg/(L·h)),随后不断降低。该菌不仅适用于不同pH、盐度废水的生物处理,还可以与硫酸盐还原菌混合添加到厌氧消化池中以减少硫化物的形成,从而减轻后者对污水处理系统中的金属设备和管道的腐蚀作用以及硫化氢对大气的污染。     

均匀设计法优化高丽参多糖的提取

利用均匀设计法优化了高丽参多糖的提取过程.主要考察料液质量比、浸泡时间、提取温度和提取时间四个因素对提取率的影响.通过数学模型得到最优提取状况和3D曲面图.结果表明,提取温度对高丽参多糖得率影响最大,在料液质量比1:35、浸泡时间135 min、水提取温度81℃条件下提取156 min,高丽参多糖最大理论提取率为49.51%.最优化模型下实际多糖得率49.29%与理论得率相符.     

一株饵料微藻与益生菌混合固定化培养条件的优化

目的:一株饵料微藻与益生菌混合固定化培养条件的优化.方法:在单因素实验基础上,采用U*6(64)均匀设计表,对海藻酸钠浓度、氯化钙浓度、藻的接种量和菌的接种量进行优化实验.并采用DPS软件对实验结果进行分析,以获得适宜的混合固定化条件;并按照此优化条件对混合固定化和单藻、单菌固定化胶球中微藻和益生菌的生长速率进行比较.结果:①获得适宜的混合固定化条件为:海藻酸钠浓度4%,氯化钙浓度1.2%.藻接种量为21.9889×102个细胞,菌接种量为58.7676×109个细胞;②混合固定化胶球中藻细胞的生长速率比单藻固定化胶球中的藻的生长速率提高了18.8%;菌的平均生长速率比单菌固定化胶球中的菌的平均生长速率提高了92.6%:结论:该实验首次对饵料微藻和海洋益生菌的混合同定化培养条件进行优化.发现藻菌混合固定化胶球中藻和菌的生长速率比单独固定化均有较明显提高.实验结果说明,在混合固定化的微环境体系中,特定的藻菌株具有相互促进生长的作用.实验结果为藻菌混合固定化技术的应用和发展提供了必要的实验数据和理论基础.     

均匀设计优化建兰ISSR-PCR体系

采用均匀设计,对影响建兰ISSR-PCR体系的引物、Mg^2＋、dNTP和Taq DNA聚合酶浓度等进行4因素5水平和4因素3水平两轮优化,建立了适合于建兰ISSR-PCR的反应体系：在20μL反应体系中,舍引物0．25μmol／L、Mg^2＋ 2．5mmol／L,dNTP0．2mmol／L、Taq DNA聚合酶1.5U和模板DNA40ng．在此基础上对扩增程序中的循环次数和退火温度,以及ISSR引物进行筛选．筛选获得的扩增程序为：94℃预变性5min;接着进行32个循环：94℃变性35S,52～56℃退火45S,72℃延伸90s;循环结束后,72℃延伸10min．同时筛选得到14个扩增稳定、多态性丰富的ISSR引物．     

均匀设计法优化发菜细胞悬浮培养条件

通过摇瓶发酵实验研究了培养温度、光照强度等培养条件对发菜细胞悬浮培养生物量和代谢产物发菜多糖累积的影响,通过均匀设计试验对培养条件进行了优化。结果表明:在培养温度24℃、培养基初始pH8.0、光照强度60μmol/(m2.s)、转速150r/min的条件下培养20d,发菜细胞生物量(细胞质量浓度)达到1.34g/L,胞外多糖产量达到208.32mg/L;与优化前相比,发菜细胞生物量和胞外多糖产量分别提高27.3%、111.17%。     

均匀设计法优化黄芩愈伤组织培养基

目的:优化黄芩愈伤组织培养条件。方法:采用均匀设计法,以黄芩甙含量为主要考察指标,对黄芩愈伤组织生长的MS培养基成分进行多因素多水平考察。结果:最佳培养基为MS附加0.25mg/L NAA、0.5mg/L 6-BA、17g/L葡萄糖和35g/L蔗糖。最佳培养基黄芩甙含量为27.44mg/gDW。结论:用均匀设计法优化愈伤组织培养基省时、方便,且最佳培养基黄芩甙含量与预测值相近,且明显高于均匀设计实验方案中的黄芩甙含量。经SAS软件分析得出的优化方程拟合度很好。     

均匀设计优化毛竹EST-SSR PCR反应体系

本研究以毛竹叶片DNA为模板,利用均匀设计U10(54)表,对毛竹EST-SSRPCR反应体系的TaqDNA聚合酶、Mg2+、dNTPs及引物浓度4因素5个水平进行优化筛选。优化实验结果表明,毛竹EST-SSRPCR的25μL优化反应体系为:10×PCRBuffer(含Mg2+)2.5μL、TaqDNA聚合酶1.5U,Mg2+、dNTPs及引物的最适浓度分别是1.0mmol/L、0.1mmol/L、0.48μmol/L;通过梯度PCR试验筛选得到相应引物的最佳退火温度为52.4℃。对优化出的EST-SSRPCR反应体系进行稳定性检测,结果均能获得丰富、稳定、清晰可辨的DNA谱带。该优化体系为利用EST-SSR分子标记对毛竹进行遗传多样性等相关研究工作提供了基础条件。     

玫瑰色微球菌A-04的红色素鉴定及稳定性分析

从石油污染的土壤和水样中筛选出一株玫瑰色微球菌A-04 Micrococcus roseus,对其所产红色色素进行了分离,并初步鉴定了色素种类,基于对影响A-04色素稳定性的单因素分析基础之上,采用3因素3水平响应面分析法,进一步对影响色素稳定性的主要因素进行了优化分析。结果表明A-04所产红色色素为类胡萝卜素,对该菌株的色素稳定性的单因素条件分析,色素对环境条件的耐受性较好,在80℃、pH5. 0～8. 0等条件下依然能长时间保持鲜红而不褪色。经响应面优化分析表明:温度、pH和溶剂是影响该色素稳定性的主要因素,温度与溶剂的交互作用对色素稳定性的影响也较为明显。pH5. 0～8. 0之间时,在80℃范围内,温度越低,同时溶剂的极性越大,越有利于维持色素的稳定性。本研究结果为该色素的实际开发和应用奠定了基础。     

Process of simultaneous hydrogen sulfide removal from biogas and nitrogen removal from swine wastewater

The feasibility of a new flowchart describing simultaneous hydrogen sulfide removal from biogas and nitrogen removal from wastewater was investigated. It took 30 days for the reactor inoculated with aerobic sludge to attain a removal rate of 60% for H₂S and NO_x–N simultaneously. It took 34 and 48 days to attain the same removal rate for the reactor without inoculated sludge and the reactor inoculated with anaerobic sludge respectively. The reactor without inoculated sludge still operated successfully, despite requiring a slightly longer startup time. The packing material was capable of enhancing the removal efficiency of reactors. Based on the concentration of NO_x–N and H₂S in the effluent, the loading rate and the ability of the system to resist shock loading, the performance of the reactor filled with hollow plastic balls was greater than that of the reactor filled with elastic packing and the reactor filled with Pall rings.     

Evaluation of pilot-scale modified A2O processes for the removal of nitrogen compounds from sewage

In this study, pilot-scale experiments for the removal of nitrogen from sewage obtained from a county Y sewer system were performed using modified A₂O processes. Using this approach, the total amount of nitrogen discharged during denitrification of the influent was average 38.6 mg/L and a level of average 10.8 mg/L was maintained throughout the denitrification process, which resulted in an average removal efficiency that was greater than 72%. The nitrogen components in the effluent water consisted of 22% ammonia nitrogen, 6% nitrite nitrogen and 72% nitrate nitrogen, reaching a nitrification efficiency of 94%. In conclusion, since these advanced treatment methods, which involve modified A₂O processes, were successfully employed to remove nitrogen from sewage discharge, they hold promise for wide spread use by treatment plants.     

光氧环境对紫色硫细菌YL28去除无机三态氮的影响

【背景】光和氧是制约光合细菌生长代谢进而影响其除氮效果的重要因素。不产氧光合细菌紫色硫细菌——海洋着色菌(Marichromatium gracile) YL28能以亚硝氮为唯一氮源进行光合生长,对高浓度无机三态氮具有良好去除能力。【目的】阐明YL28菌株除氮效率与光氧环境的交互联系,获得其生物除氮的最适光氧条件。【方法】以高浓度无机三态氮共存海水水体为研究体系,在有光/无光条件下考查装样量(表征体系溶氧状态)对YL28菌株生物除氮活性的影响,并通过响应面分析法对装样量、光照强度和光周期3个主要因素进行优化。【结果】光照且氧浓度较低时(80%装样量),YL28具有最佳生长和无机三态氮去除能力;装样量在10%-100%时,菌体生物量(OD_(660))在0.938-2.719之间,当氨氮、亚硝氮和硝氮分别为7.16、5.67和4.83mmol/L时,其去除率分别在71.44%-89.09%、99.22%-99.83%和91.60%-97.33%。黑暗条件下,装样量在20%-100%时,氨氮、亚硝氮和硝氮去除率分别在48.07%-64.27%、73.51%-86.42%和42.57%-46.34%,但菌体生物量(OD_(660)为0.615-0.903)明显降低。通过响应面优化,当装样量、光照强度和光周期分别为80.0%(溶氧量约为0.32 mg/L)、2 800 lx和24L:0D时,细胞生长和氨氮去除活性达到最佳状态,分别比优化前提高了21.28%和14.11%。在实际应用中,选取72%-89%装样量(溶氧量约为0.26-0.63mg/L)、2240-3460lx光照强度和21L:3D-24L:0D光周期,细胞活性可达95%以上。【结论】80%装样量有助于促进菌体光照生长和除氮;在黑暗有氧和无氧环境下,YL28菌株也具有较好除氮活性,这为不产氧光合细菌在生物反应器中高效去除无机三态氮的应用提供了有价值的参考数据。     

Growth and removal of nitrogen and phosphorus by free-living and chitosan-immobilized cells of the marine cyanobacterium Synechococcus elongatus

This study investigated the growth rate of chitosan-immobilized cells of the marine cyanobacterium Synechococcus elongatus and its potential application in the removal of nitrogen and phosphorus for wastewater treatment. Immobilized cell cultures had a lag phase of growth due to the immobilization method, and their growth rate was similar to that of free-living cell cultures. Ammonia removal was higher in free cells (54%) than in immobilized cells (29%), but nitrate removal was similar in immobilized (38%) and free cells (44%); phosphorus removal was more efficient in free cells (88%) than in immobilized cells (77%). Chlorophyll a and protein content were higher in immobilized cells. Our study demonstrates that S. elongatus immobilized into chitosan capsules can remove nutrients and is able to maintain a growth rate comparable to that of free cells in culture.     

Studies on the optimization of growth and indole alkaloid production by hairy root cultures of Catharanthus roseus

Catharanthus roseus hairy root cultures, genetically transformed with Agrobacterium rhizogenes, produce a wide variety of indole alkaloids. The effect of sucrose, phosphate, nitrate, and ammonia concentrations on growth and indole alkaloid production of C. roseus hairy root cultures were studied by using statistical experimental designs and linear regression analysis. Contradictory effects of these nutrients on growth and indole alkaloid production were found. The maximal growth was obtained by having 77. 8 mg NaH(2)PO(4) . H(2)O/L and 1. 311 g KNO(3)/L in the medium, whereas the specific production of alkaloids was highest at the lowest levels of all the nutrients studied. The maximal dry weight was obtained with high values of sucrose and ammonia, but clear optimum concentrations could not be found. When having enough nutrients to support reasonable growth, it appeared difficult to affect the specific alkaloid production rates considerably. The growth (dry wt.) with the optimized nutrient concentrations in the medium was more than 50% better than in the control medium with about the same alkaloid production.     

Organic carbon and nitrogen losses influenced by vegetation removal in a semiarid mediterranean soil

A reduction in plant cover can lead to an increase in the erosionprocesses that diminish soil quality. Any rise in temperature resulting frompredicted climate changes may aggravate this effect, particularly in semiaridMediterranean areas. Bearing this in mind, the capacity of a soil to preserveorganic matter becomes very important if the soil is to maintain its physicaland chemical properties. Soil organic carbon and nitrogen changes wereevaluatedin a non-disturbed (with natural vegetation) and a disturbed (all vegetationmanually clipped to ground level) pine system. Nine years after vegetationremoval significant differences (p < 0.01) were found in the soil organiccarbon content between plots (top 20 cm), but not in totalnitrogen. In the disturbed plot 0.0232 Mg ha^–1y^–1 of soil organic carbon were lost through erosionand4.30 Mg ha^–1 y^–1 throughmineralization. In the first 48 months after vegetation removal the soilorganiccarbon content fell from 40.3 to 28.0 g kg^–1. Inthe last 60 months of the experiment the amount of organic carbon in the soilfell from 28.0 to 27.7 g kg^–1. This result wasmainly attributable to the intense oxidization, which took place during thefirst 60 months, of organic matter linked to the coarse soil mineral fraction.Up to the 72^nd month the losses by erosion were a total of 532.7g, which rose to 1284.4 g by the end of theexperiment(108 months). The effect of vegetation removal in a Mediterranean semiarid arealeads to a rapid decline in the amount of organic carbon stored in the soil.Such perturbation is irreversible if left to nature.     

Comparison of quasisteady-state performance of the DEAMOX process under intermittent and continuous feeding and different nitrogen loading rates

The recently developed denitrifying ammonium oxidation (DEAMOX) process combines the anammox reaction with autotrophic denitrifying conditions using sulfide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. This paper compares a quasisteady-state performance of this process for treatment of baker's yeast wastewater under intermittent and continuous feeding and increasing nitrogen loading rate (NLR) from 300 till 858 mg N/L/d. The average total nitrogen removal slightly decreased on increasing the NLR: from 86 to 79% (intermittent feeding) and from 87 to 84% (continuous feeding). The better performance under continuous feeding was due to a more complete nitrate removal in the former case whereas the ammonia removal was similar for both feeding regimes under the comparable NLR. A possible explanation can be that, during continuous feeding (simultaneous supply of nitrate and sulfide), there were less mass transfer limitations for sulfide oxidizing denitrifiers presumably located in the outer layer of sludge aggregates. On the contrary, the ammonia oxidisers presumably located inside the aggregates apparently suffered from nitrite mass transfer limitations under both the feedings. The paper further describes some characteristics of the DEAMOX sludge.