化感链霉菌6803菌株液体发酵工艺优化的研究

土壤微生物链霉菌6803菌株被证明对高等植物具有化感作用。采用单因子实验方法,研究液体发酵碳源、氮源、无机盐、发酵温度、发酵液初始pH值、摇床转速、发酵时间等对链霉菌6803菌株菌丝体产量及发酵液化感作用的影响,用均匀试验设计法优化了发酵工艺条件。结果表明：链霉菌6803菌株生长和产生化感作用的最佳发酵条件为：p（淀粉）=26．67g·L-1,p（蔗糖）=25．15g·L-1,p（NH4C1）=0．30g．L-1,黄豆饼粉浸液8．88％,所（NI-h）H2P04]=O．18g·L-1,p（FeS04．7H20）=O．002g·L-1,p（NaCl）=0．75g·L-1,pH值7．6,装量系数O．16,接种量3％,温度36℃,转速200r·min-1,发酵144h。本研究为利用微生物次生代谢产物作为天然除草剂奠定了基础。     

一株产耐热纤维素酶菌株的筛选及酶学性质

采用纤维素刚果红平板法从大田蘑菇种植场建堆的稻草样中分离得到了1株能产具有较好温度耐受性和pH稳定性的纤维素酶的放线菌DY3.综合形态、生理生化特征以及16S rDNA序列分析,将其初步鉴定为嗜热裂孢菌(Thermobifida fusca).对该菌所产纤维素酶的性质研究表明:最适催化温度为65℃,在70℃保温60 min后仍有75%以上的活力;最适催化pH为7.5,在pH 5.5～10.0之间该酶的稳定性较好,pH 10.0的条件下仍有80%的活力;最适作用底物是羧甲基纤维素钠.研究可为木质纤维素的生物预处理提供一定参考价值.     

一株丁二酮高产菌株的鉴定及发酵条件优化

天然丁二酮是一种香精载体,为提高其产量,有必要筛选出丁二酮高产菌株及其最佳发酵条件.从保存的一株丁二酮高产菌株6-1(2)出发,通过分子生物学方法对其进行鉴定,采用单因素试验和最佳单因素组合实验的方法筛选出该菌株的最佳发酵条件.结果表明,实验菌株6-1(2)与植物乳杆菌Lactobacillus plantarum的AB326301.1序列同源性最高,初步鉴定为植物乳杆菌;发酵条件经过优化后,丁二酮的产量从初始的38 mg/L提高到167.56 mg/L,提高了340.95%,产量提高显著.优化发酵条件为:牛肉膏10 g/L,柠檬酸氢二胺2 g/L,酵母浸粉15 g/L,磷酸氢二钾2 g/L,乙酸钠2 g/L,葡萄糖20 g/L,蛋白胨30 g/L,吐温-80 1 mL/L,初始pH 6.2-6.4,接种量1.5%,37℃静置培养10 h;该发酵条件下的丁二酮产量提高显著.本研究对丁二酮的工业化生产具有一定的参考价值.     

拮抗放线菌T111菌株鉴定、发酵液理化性质测定及发酵条件优化

为明确放线菌T111在植物病害生物防治中的应用潜力,通过形态观察、生理生化测定结合16S rDNA序列分析确定了其分类地位,采用平板打孔法测定了发酵液的理化性质,并采用单因素试验与正交设计方法筛选出该菌株的优化发酵配方和发酵条件.结果表明,T111与黄色链霉菌Streptomyces flaveus strain NBRC3359(AB184749)序列的同源性最高,初步鉴定为黄色链霉菌(Streptomyces flaveus).该发酵液对黄瓜菌核、黄瓜蔓枯、棉花红腐病菌等有较高的抑制活性;贮存稳定性和热稳定性良好,4℃贮存60 d,抑菌活性为对照的88.3%,80℃处理60 min抑菌活性为对照的90.9%;对pH值较敏感,在pH 5～7时活性较高;对紫外线稳定,紫外光照射12 h,其活性基本不受影响.培养基优化组合为:可溶性淀粉20 g,大豆蛋白胨5 g,NaNO3 20 g,FeSO4 0.5 g,去离子水1 000 mL;优化发酵条件为:发酵温度27℃,发酵时间5 d,初始pH 6.0,接种量5%,装液量75 mL/250 mL,摇床转速150 r min-1.图6表2参18     

放线菌产纤维素酶固定化研究

选择琼脂、明胶、琼脂-明胶3类固定化载体对具有降解纤维素能力的放线菌2235产生的纤维素酶进行固定化,在分别以羧甲基纤维素钠( CMC - Na)和滤纸为底物条件下,通过测定不同方法固定化后的纤维素酶活性,确定用于固定化纤维素酶的优良载体.结果表明,明胶法固定化效果最差;琼脂-明胶协同法固定化效果最优,采用该方法测得的滤纸酶和CMC酶活性分别可达3 317和8 868 nkat·mL-1.     

发酵木糖产乙醇酵母菌的选育及其发酵特性

为了提高木质纤维素水解产物中戊糖的利用率,采用划线分离法、TTC(2,3,5-氯代三苯基四氮唑)法从多年生乔木下方土壤及林中朽木中筛选出4株能利用木糖产乙醇的酵母菌。其中1株产乙醇能力较佳,其发酵条件为150 r/m in、30℃、接种量12%、初始pH值6.0时,乙醇产量达4.88g/L,木糖转化率达理论值的24.3%。经初步鉴定,该菌为假单丝酵母属(Cand ida)。研究还表明,该菌株在pH 6.5,温度40℃仍能很好地发酵木糖产乙醇。     

产中性纤维素酶芽孢杆菌Y106产酶条件优化

筛选得到一株高产中性纤维素酶的芽孢杆菌Ｙ１０６,并对其发酵条件进行了优化,麸皮能够较大幅度地促进产酶,果糖是良好的诱导物,有机氮流促进产酶的效果优于无机氮源,最优的有机氮源是蛋白胨。Ｆｅ＾３＋、Ｆｅ＾２＋、Ｎａ＾＋、Ｃａ＾２＋可以促进纤维素酶的合成,而Ｃｕ＾２＋、Ａｇ＾＋、Ｃｏ＾２＋、Ｈｇ＾２＋则对合成起遏制作用,在酶反应系统中Ｆｅ＾３＋、Ｆｅ＾２＋、Ｃａ＾２＋、Ｍｇ＾２＋能激活纤维素酶活性,Ｃｏ     

碱性β—聚糖酶产生菌选育及产酶条件优化

从碱性土样中分离到数十株产碱性β－聚糖酶类的细菌经摇瓶反复筛选后,得到一株碱性β－聚产产量较高的耐碱细菌经初步鉴定,属短小芽孢杆菌,其纤维素酶作用的最适ＰＨ为７．６,最适θ为６０℃,木聚糖酶的作用最适ＰＨＪ为９．０,最适θ为５５℃,该菌的最适生长ＰＨ为８．０,最适产酶θ为２８－３２℃,木聚糖与山梨糖分别是木聚糖酶和纤维素酶的良好诱导物,以麸皮为碳源,产酶的最适浓度为５％,添加尿素和（ＮＨ４）２ＳＯ     

响应面法优化菌株Bacillus sp.W77酯酶发酵条件

为开发适应性好的工业用酶,从深圳福田红树林自然保护区土壤中分离纯化获得一株产耐高温嗜碱性酯酶的菌株,通过形态学和分子生物学初步鉴定该菌株为芽孢杆菌属(Bacillus sp.),命名为Bacillus sp.W77;对所产的粗酶液进行酶活测定,发现该菌产的酯酶的最适反应温度是50℃,最适pH为8.0,且在碱性条件下较稳定;采用响应面法(Response surface methodology)对土壤菌株Bacillus sp.W77的产酯酶条件进行了优化,酵母提取物6.67 g/L,磷酸氢二钾0.56 g/L,硫酸镁0.36 g/L时,此时预测的最大酯酶活力的D405 nm值为1.266,在最佳产酶条件下,优化后酯酶活力的D405 nm值由0.829提高到1.235,实际值达到理论预测值的97.5%.     

氢化可的松高转化菌株的选育及其发酵条件

利用酮康唑抗性突变选育氢化可的松高转化菌株，即将经过紫外线诱变处理的新月弯孢霉原生质体倾注于含有酮康唑最小抑制浓度(10μmoL／L)的培养基平板上，获得了136株酮康唑抗性突变株，氢化可的松转化率高于出发菌株的有14株．其中抗性突变株KA-91，其氢化可的松转化率为出发菌株的1．42倍，达到68．05％．研究了菌株的发酵性能，优化了培养基组成和发酵工艺条件，氢化可的松转化率达到73．6％．图7表3参5     

Practical consideration for design and optimization of the step feed process

Based on the anoxic/oxic (A/O) step feed process, a modified University of Cape Town (UCT) step feed process was developed by adding an anaerobic zone and adjusting sludge return pipeline. Performance evaluation of these two types of processes was investigated by optimizing operational parameters, such as the anaerobic/anoxic/oxic volumes, internal recycle ratios, and sludge retention times, for removal of chemical oxygen demanding (COD), nitrogen, and phosphorus. Results showed high removal efficiencies of COD of (85.0±1.7)%, ammonium of (99.7±0.2)%, total nitrogen (TN) of (85.5±1.7)%, phosphorus of (95.1±3.3)%, as well as excellent sludge settleability with average sludge volume index of (83.7±9.5) L·mg^-1 in the modified UCT process. Moreover, (61.5±6.0)% of influent COD was efficiently involved in denitrification or phosphorus release process. As much as 35.3% of TN was eliminated through simultaneous nitrification and denitrification process in aerobic zones. In addition, the presence of denitrifying phosphorus accumulating organisms (DNPAOs), accounting for approximately 39.2% of PAOs, was also greatly beneficial to the nitrogen and phosphorus removal. Consequently, the modified UCT step feed process was more attractive for the wastewater treatment plant, because it had extremely competitive advantages such as higher nutrient removal efficiencies, lower energy and dosages consumption, excellent settling sludge and operational assurance.     

生态环境脆弱地区城市化发展特征及城市发展路径选择流程研究

脆弱的生态环境会对城市化进程产生一定的约束作用。生态环境脆弱地区的城市化,表现出与非脆弱地区不同的特征。以往的研究,更倾向于对各类生态环境脆弱地区分别进行研究。本文试图站在更宏观的角度,通过研究生态环境脆弱和非脆弱地区这两个大类在城市化发展方面的异同,明确生态环境脆弱地区城市化发展的特征及合适的路径。首先在阅读了大量国内外相关文献的基础上,总结了干旱区、喀斯特地区、高寒地区、过渡区等类型的生态环境脆弱区的共性,了解其城市化现状及约束因素,并结合学者们的研究,与生态环境良好地区的城市化进行了对比,提出发展的对策。在理论分析的基础上,文章第二部分初步构建了一个生态环境脆弱地区城市化发展路径的选择方法及流程。研究表明生态环境脆弱区城市化的制约因素主要有地质条件、地形、水文、气候、植被和地上地下自然资源等,与生态环境良好地区城市化的差异主要体现在产业选择、人口承载力及城市建设用地等方面,这些方面也是该类地区在城市化过程中应格外重视的。生态环境脆弱地区城市化路径选择流程主要分为以下几个步骤：归类、分析城市化水平及阶段、分析生态环境演变历程、研究城市化与生态环境的相互作用机制、情景分析、制定战略规划,确定城市的功能、定位等。     

苏云金芽孢杆菌生物杀虫剂发酵生产的影响因素及其工艺选择

化学杀虫剂的长期使用给生态环境造成了严重破坏,也使害虫种群的抗药性日益提高,生物杀虫剂以其＂绿色环保＂的特点引起人们的广泛关注。其中,苏云金芽孢杆菌（Bacillus thuringiensis）制剂是目前世界上产量最大、应用最广的生物杀虫剂。它对鳞翅目、双翅目、鞘翅目、螨类等许多有害昆虫有毒杀作用,而对人类、动物和农作物无害。长期以来,人们一直致力于苏云金芽孢杆菌发酵过程的研究,以期获得高毒效的生物杀虫剂产品。本文首先对苏云金芽孢杆菌发酵生产的各种影响因素进行了综合分析,将影响因素分为培养条件和培养基组分两类,得出最佳培养条件为温度：（30±1）℃,pH：7.0±0.1,搅拌速度：400～600r·min-1,通气量：1∶0.6～1.2（发酵培养基体积与每分钟通入空气的体积之比）,接种时间：对数期初;最佳培养基配比为碳氮比：8～10∶1,无机盐含量：KH2PO4或K2HPO4为0.075%～0.2%;MgSO4·7H2O为0.075%～0.3%;CaCO3为0.075%～0.15%;MnSO4·H2O、FeSO4·7H2O各为0.002%。其次,对当前研究与工业化生产中的各种发酵工艺进行了评述,总结了现有发酵工艺的优缺点。在现有研究基础上,降低培养基原料成本、改进发酵工艺和采用基因学手段构建高效工程菌株将成为未来研究热点。     

Photo-Fenton oxidation of Orange G azo dye: process optimization and mineralization mechanism

Environmental Chemistry Letters - Textile effluents containing synthetic dyes are one of the most important sources of water pollution. Several dyes are toxic to the aquatic life and...     

Genetic evidence for the “good genes” process of sexual selection

The adaptive nature of female mate choice remains one of the most contentious issues in the study of sexual selection. Here, I provide evidence that mate choice by females of the ovoviviparous cockroach Nauphoeta cinerea influences the rate at which offspring develop and provides both direct and indirect benefits to the female. Males that are more attractive to females produce offspring with shorter development times than less preferred males. Development time is heritable and apparently unconstrained by antagonistic pleiotropy. Male attractiveness and rate of offspring development are genetically correlated. Offspring gain an indirect benefit from their mother's mate choice because, on average, individuals that hatch faster reach sexual maturity more quickly. Females that discriminate among males gain a direct benefit because N. cinerea is ovoviviparous and the time between clutches is decreased by producing offspring with shorter development. In addition to providing evidence for beneficial consequences of mate choice, this study highlights how genetic data provide insights into the process of sexual selection not gained in a purely phenotypic study.Communicated by P. Pamilo     

Degradation of refractory organics in concentrated leachate by the Fenton process: Central composite design for process optimization

• 90% total COD, 95.3% inert COD and 97.2% UV₂₅₄ were removed. • High R² values (over 95%) for all responses were obtained with CCD. • Operational cost was calculated to be 0.238 €/g COD_removed for total COD removal. • Fenton oxidation was highly-efficient method for inert COD removal. • BOD₅/COD ratio of leachate concentrate raised from 0.04 to 0.4. The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic pollutants. Within this framework, this study focuses on the treatability of leachate nanofiltration concentrate through Fenton oxidation and optimization of process parameters to reach the maximum pollutant removal by using response surface methodology (RSM). Initial pH, Fe²⁺ concentration, H₂O₂/Fe²⁺ molar ratio and oxidation time are selected as the independent variables, whereas total COD, color, inert COD and UV₂₅₄ removal are selected as the responses. According to the ANOVA results, the R² values of all responses are found to be over 95%. Under the optimum conditions determined by the model (pH: 3.99, Fe²⁺: 150 mmol/L, H₂O₂/Fe²⁺: 3.27 and oxidation time: 84.8 min), the maximum COD removal efficiency is determined as 91.4% by the model. The color, inert COD and UV₂₅₄ removal efficiencies are determined to be 99.9%, 97.2% and 99.5%, respectively, by the model, whereas the total COD, color, inert COD and UV₂₅₄ removal efficiencies are found respectively to be 90%, 96.5%, 95.3% and 97.2%, experimentally under the optimum operating conditions. The Fenton process improves the biodegradability of the leachate NF concentrate, increasing the BOD₅/COD ratio from the value of 0.04 to the value of 0.4. The operational cost of the process is calculated to be 0.238 €/g COD_removed. The results indicate that the Fenton oxidation process is an efficient and economical technology in improvement of the biological degradability of leachate nanofiltration concentrate and in removal of resistant organic pollutants.     

Influence of dung volatiles on the process of resource selection by coprophagous beetles

Summary. Most dung beetles colonize the faeces of several vertebrate species without much discrimination, and are thus often considered as polyphagous. Recent studies have provided evidence for clear feeding preferences in scarab beetles colonizing dung of herbivore species, but little is known about these insects’ abilities to discriminate among odours from faeces of various herbivores. In this study, trophic preferences were examined using blocks of pitfall traps baited with dung from four different herbivore species, i.e., sheep, cattle, horse, and red deer, in a mountainous area of south-central France. 4941 coprophagous scarabs, belonging to 27 species, were captured. Beetles were more attracted to dung of sheep (2257 individuals) than that of cattle (1294 individuals), followed by deer dung (768 individuals) and horse dung (622 individuals). Eleven of the 27 beetle species collected had significant feeding preferences for one of the four dung types. For each insect species, trophic habits did not vary between the two different sites of trapping, an open pasture and a wooded habitat. In laboratory olfactometer bioassays, scarab beetles orientated preferentially towards the dung volatiles from the dung type they preferred in the field. Trypocopris pyrenaeus, Anoplotrupes stercorosus, and Aphodius rufipes were more attracted to volatile compounds from sheep dung, Onthophagus fracticornis significantly preferred horse dung volatiles, and Aphodius haemorrhoidalis responded positively to deer dung odours. The role of dung olfactory cues in the process of resource selection by dung beetles is discussed.     

Sexual selection and cuckoldry in a monogamous songbird: implications for sexual selection theory

Sexual selection is generally assumed to be weaker in monogamous than in polygynous animals. Recently, though, extra-pair fertilizations have been hailed as an important force in generating variance in reproductive success among males in socially monogamous species, thereby increasing the intensity of sexual selection. To see if extra-pair copulations contribute to variance in male reproductive success in the house finch (Carpodacus mexicanus), we used DNA fingerprinting to determine the paternity of chicks from 35 nests. This species is a socially monogamous passerine in which plumage brightness serves as a sexually selected indicator of male quality. Out of 119, nestlings 10 (8.3%) were fathered by a male other than the attending male, but cuckoldry occurred randomly with respect to the plumage colouration, size, or age of the attending male. Thus extra-pair fertilizations do not generate variance in male reproductive success with respect to plumage colour. On the other hand, a strongly male-biased sex ratio and asynchronous breeding by females may generate substantial variance in male reproductive success and could explain the evolution of ornamental colouration.