松毛虫赤眼蜂携带球孢白僵菌防治亚洲玉米螟技术研究与应用

高效的载菌技术是提高载菌赤眼蜂防治效果的重要基础。本研究对比了不同吸附助剂对松毛虫赤眼蜂羽化时间、羽化量、存活时间及载菌量影响,证明了不同助剂及吸附球孢白僵菌分生孢子后对赤眼蜂无不利影响。试验结果表明,0.1%（w/v）淀粉溶液作为吸附助剂可显著提高赤眼蜂的载菌量,达3.6×10⁴孢子/蜂以上,并应用该助剂建立了赤眼蜂高效携带白僵菌方法。从被害株数、蛀孔数、活虫数和僵虫数4个方面测定了载菌赤眼蜂田间防治玉米螟效果。结果表明,载菌赤眼蜂较单一使用赤眼蜂防治效果显著提高,被害株数、蛀孔数和活虫数均显著降低,分别降低了28.1%、22.8%和24.5%,并且载菌赤眼蜂处理组中僵虫数量显著高于单独使用赤眼蜂处理组,说明载菌赤眼蜂对玉米螟具有协同防控作用。利用该方法进行玉米螟田间防治,能够降低防治成本,提高防治效率,节约劳动力,具有巨大的应用和推广价值。     

秸秆复合有机酿热物对大棚土壤环境的影响

为解决黑龙江省早春大棚土壤温度低及设施土壤环境恶化问题,以‘千禧’番茄为材料,研究秸秆+牛粪(NGH)、秸秆+马粪(MGH)、秸秆+羊粪(YGH)、单一秸秆(JG),以未进行反应堆技术为对照(CK),对早春大棚‘千禧’番茄土壤温度、土壤理化性状、酶活性及微生物群落结构的影响。结果表明,与对照相比,各处理降低了土壤pH,提高了土壤温度、土壤EC、碱解氮、速效钾、有机质含量及土壤蔗糖酶、脲酶、磷酸酶、过氧化氢酶活性。经过秸秆生物反应堆处理的20 cm土层温度有明显的提升,其中秸秆+羊粪处理在反应启动后提升土壤温度效果最好;秸秆+羊粪(YGH)处理提高了土壤速效磷含量,是对照的2倍;秸秆+羊粪(YGH)处理土壤中4种酶活性均处于最高水平,分别比对照提高了91.9%、220%、18.5%、7.3%。各处理微生物多样性指数均显著高于对照,变化规律一致为秸秆+羊粪(YGH)>秸秆+牛粪(NGH)>秸秆+马粪(MGH)>秸秆(JG)>对照(CK);秸秆+羊粪(YGH)及秸秆+牛粪(NGH)处理对糖类、氨基酸类、酯类、醇类、胺类、酸类6类碳源的利用能力最强,显著高于其他处理和对照。应用主成分分析和聚类分析方法将大棚番茄土壤分为4个等级,秸秆+羊粪(YGH)处理为第一级,秸秆+牛粪(NGH)处理为第二级,秸秆+马粪(MGH)及单一秸秆(JG)处理为第三级,对照(CK)为第四级。应用秸秆复合有机酿热物生物反应堆促进了土壤环境的改善,以秸秆+羊粪(YGH)作为复合有机酿热物效果最佳。     

菜地土壤中纤维素降解菌的筛选及其产酶条件优化

利用传统的微生物学方法,从菜地土壤中筛选出高产纤维素酶的菌株,并对其产酶条件进行优化。结果表明,从4种菜地土壤中共分离获得16株纤维素降解菌,其中生菜地土壤中获得的菌株最多,白菜地土壤中获得的菌株最少;在16个菌株中,从油菜地中分离纯化的1个菌株具有最强的纤维素降解能力;对该菌株的产酶条件优化发现,以麸皮作为唯一碳源、培养温度35℃、培养时间96 h时酶活力最高。     

鸡粪除臭菌的分离筛选及除臭效果分析

以鸡粪堆肥为材料,筛选高效除臭菌株并构建复合菌系,为鸡粪的无害化处理提供具有除臭功能的菌种资源。首先,采用驯化富集法、平板稀释法、产气试验、除氨试验、除硫化氢试验以及纤维素降解试验筛选出鸡粪堆肥中的除臭菌;其次,通过16S rRNA基因测序鉴定菌株;最后,通过拮抗试验构建除臭菌系。研究分离得到5株具有除臭功能的菌株,分属于芽孢杆菌属(MS03,Bacillus sp.)、贝莱斯芽孢杆菌(MS07,Bacillus velezensis)、耐寒短杆菌(MS11,Brevibacterium frigoritolerans)、木糖葡萄球菌(MS42,Staphylococcus xylosus)和变异棒杆菌(MS82,Corynebacterium variabile)。复合菌系C2(MS03+MS07)和C4(MS03+MS82)的综合除臭率均高于60%,且明显高于单株菌株及其他复合菌系。研究表明,这两个由不同除臭菌组合而成的复合菌系在无害化处理鸡粪方面具有较大的潜力和应用前景。     

养殖尾水处理系统填料生物膜氮循环微生物功能特征

为探讨填料生物膜在养殖尾水处理中对水体氮循环的影响机制,采用16S rRNA基因扩增子测序和宏基因组测序技术,对填料生物膜、水体细菌的群落结构及其与氮循环相关的功能基因丰度差异特征进行了研究。结果显示,填料生物膜微生物主要参与氮代谢活动。在属水平上,Pseudomonas、Spirochaeta、Opitutus和Syntrophus是填料生物膜氮素转化过程的重要功能微生物类群。与水体相比,填料生物膜的碳代谢活动能力较强（P<0.05）;填料生物膜上固氮功能基因nifH、硝化功能基因hao、反硝化和异化硝酸盐功能基因napA、nirS、norB、norC、nrfA、nirB和氮代谢调控基因ntrC及其相应的关键酶均显著高于周围水体（P<0.05）,且对含氮污染物有显著去除效果。研究表明,养殖尾水处理系统内复合填料生物膜具有比周围水环境更强的氮周转能力,主要通过关键功能物种介导的固氮和反硝化作用实现养殖尾水氮素的转化和迁移。研究结果作为野外实验证据,可为复合填料生物膜系统在水产养殖尾水治理中的应用提供理论依据。     

黄土高原马铃薯不同连作年限土壤 理化性质及微生物特性

以黄土高原旱作区马铃薯不同连作年限土壤为研究对象,采用空间代替时间序列方法,对撂荒（CK₁）、小麦/豌豆/马铃薯轮作（CK₂）、连作2 a、连作4 a和连作6 a等不同连作年限的土壤容重、结构分维、总有机碳、酶活性与微生物数量及变化规律进行研究。结果表明：(1）不同处理土壤容重差异显著,连作6 a土壤容重最小;(2）连作可以改变土壤中不同粒级团聚体的比例,各处理中＞4 mm粒径的土壤含量最高;(3）马铃薯长期连作显著降低土壤有机碳含量,连作6 a土壤总有机碳含量较撂荒降低14.27%; (4）马铃薯主要生育期内土壤转化酶、过氧化氢酶变化动态呈“S”型曲线,脲酶呈“M”型变化趋势,3种酶活性与土壤肥力因子均呈极显著正相关,与土壤容重呈极显著负相关;(5）细菌是连作土壤中优势菌,真菌和放线菌也占一定比重;细菌、真菌和放线菌数量在0～10 cm土层显著高于10～20 cm土层;马铃薯长期连作显著降低土壤微生物数量,群落结构随连作年限明显改变。     

生物菌肥和钾肥配施对苹果钾素吸收及果实品质的影响

为了研究生物菌肥和钾肥对苹果果实品质及生长发育的协同作用,以7 a生'瓦里短枝'(Vallee spur Del)为研究对象,设置T1(K2O 420 kg·hm-2)、T2(生物菌肥2520 kg·hm-2)、T3(生物菌肥2520 kg·hm-2+K2O 294 kg·hm-2)、T4(生物菌肥2520 kg·hm...     

Contribution of microorganisms to the biofilm nutritional quality: protein and lipid contents

The nutritional quality of biofilm, a microbial community associated to an organic matrix, was evaluated in artificial substrate (polyethylene screen) in net cages during 30 days in the Patos Lagoon estuary, Southern Brazil. During this period, samples of biofilm were collected each 5 days for analysis of chlorophyll a, microorganisms abundance, dry weight, protein and lipid contents. During the study, chlorophyll a varied from 0.38 to 2.75 μg cm^?2; dry weight between 7.16 and 17.63 mg cm^?2; protein content from 0.43 to 1.76 mg cm^?2 and lipid concentration between 1.21 and 4.23 mg cm^?2. The variation of lipid in the biofilm was closely related to the abundance of free heterotrophic bacteria (34.25–56.54 × 10⁶ cells cm^?2), filamentous cyanobacteria (7.5–15.9 × 10⁶ filaments cm^?2), flagellates (6.92–12.89 × 10⁶ cells cm^?2) and mainly nematodes (29–1,414 organisms cm^?2), while protein content varied similarly to the abundance of unicellular centric diatoms (52.10–179.81 × 10³ cells cm^?2), and nematodes. This information will allow a better management of food supply to raised aquatic organism with the utilization of natural productivity in the culture systems, with considerable decrease in production costs.     

A Review on Decaffeination of Tea Products

Since caffeine possesses some well-unknown adverse effects,many attempts have been conducted to remove it from tea products,including selective extraction with different solvents,enzymatic degradation and inhibition the caffeine synthesis pathway.Reports showed that caffeine can be safely and efficiently removed from fresh tea leaves by hot water blanching,however this approach is not suitable for treating the rolled or dried leaves because of the unavoidable loss of catechins.Although microwave-enhanced vacuum ice water extraction can be used for decaffeination of dried tea,time consumption seems to be the main shortage of this method.Liquefied dimethyl ether might be used as another alternative solvent for selective extraction of caffeine from tea products because of its low toxicity and residum,but its decaffeination efficiency needs to be verified furthermore.It has been proved that supercritical carbon dioxide extraction is an effective approach for removing caffeine from different types of tea products,while the application of the technique is always limited as its expensive equipments and high running costs.Decaffeination with microbe incubation or enzymatic digestion is highly hopeful since many studies showed that some microorganisms can degrade the caffeine through induced demethylase and oxidase under gentle condition in some model systems,unfortunately,this approach is far away from application since security and quality of the decaffeinated products are rarely concerned.Low-caffeine tea products can be easily produced through normal manufacture by using the leaves harvested from some low-caffeine cultivars which are derived through genetic modification or conventional breeding,but these germplasms are very limited.     

人工湿地氧化还原特征及其与微生物活性相关性

在水力负荷为800 mm/d的运行条件下,研究了复合垂直流人工湿地中试系统不同功能层面的氧化还原特征、好氧微生物数量、基质的耗氧速率及氧化还原酶类活性的分布特点。结果表明:各功能层面的氧化还原电位、好氧微生物数量、耗氧速率表层最高,并且随着基质深度的增加逐渐降低。除过氧化物酶外,氧化酶活性表现为表层高于中下层;而硝酸盐还原酶、亚硝酸盐还原酶等活性变化趋势则相反。同时,氧化还原电位与基质中细菌、真菌、放线菌的数量、耗氧速率等存在显著正相关关系;氧化还原电位与多酚氧化酶、过氧化氢酶、脱氢酶等氧化酶活性也存在显著正相关,而与下行流池的硝酸盐还原酶、亚硝酸盐还原酶等还原酶类存在显著负相关关系。