氨基葡萄糖发酵条件研究

对基因工程菌JZ2316发酵的接种量、pH及诱导剂IPTG添加时间等条件进行了研究。结果表明,该菌株的最佳发酵条件为:培养基组成为葡萄糖0.500 0 g/L、磷酸二氢钾0.667 0 g/L、一水柠檬酸0.355 0 g/L、七水硫酸镁0.250 0 g/L、二水氯化钙0.002 5 g/L、消泡剂0.025 0 g/L、微量元素母液(包括七水硫酸铁5.00 g/L、硼酸0.10 g/L、六水氯化钴0.10 g/L、一水硫酸锰0.33 g/L、七水硫酸锌3.80 g/L、二水钼酸钠0.10 g/L、硫酸钴0.10 g/L)0.010 0 g/L,流加糖为60%葡萄糖(质量体积比),pH为6.9,接种量为10%,发酵OD600 nm达到28添加诱导剂。     

高产中性纤维素酶的巨大芽胞杆菌基因工程菌发酵工艺条件优化

为了加快纤维素酶工业化应用的步伐,解决纤维素酶发酵工业产量低、生产成本高等问题,本研究采用正交设计法对高产中性纤维素酶的巨大芽胞杆菌(Bacillus megaterium)基因工程菌的培养基和发酵条件进行优化.结果表明,最佳发酵培养基成分为:麦麸2.5%、玉米浆1.5%、磷酸二氢钾0.75%、硫酸镁0.04%、氯化钠0.25%;最佳发酵条件为:温度37℃,pH 7.0,罐压0.03～0.05 Mpa,转速600 r/min,装液量3 L,接种量10%,培养4 h后以0.25 g/L/h的流速流加木糖10 h,发酵16 h后,以恒溶氧方式流加补料8 h,共补加料320mL,发酵过程控制溶氧浓度≥30%.该工程菌在此最佳发酵条件下培养,纤维素酶活力可达3846.48 U/mL,是优化前摇瓶发酵的4.3倍.本研究可为工业化生产纤维素酶提供依据.     

汽爆玉米秸秆同步糖化发酵产乙醇的工艺优化

该文对同步糖化发酵玉米秸秆生产纤维乙醇的工艺条件进行了研究,分别利用单因素试验和正交试验考察了影响发酵的工艺条件。结果显示：温度37℃、pH值4.8、底物15%（质量分数）、表面活性剂Tween-20 0.15%（质量分数）、纤维素酶用量30 U/g、酵母用2%的葡萄糖溶液活化,接种量5‰（相对底物干质量）、培养基的组成：KH2PO4 2.5 g/L,(NH4)2SO4 2.0 g/L,MgSO4·7H2O 0.15 g/L,CaCl2 0.35 g/L、发酵时间60 h为同步糖化发酵（SSF）生产乙醇的最优工艺条件,该条件下乙醇的体积分数为2.85%,乙醇得率达理论值的88.12%。     

利用木糖产乙醇酵母菌株的构建

以酿酒酵母缺陷型(Saccharomyces cerevisiae)与黏红酵母(Rhodotorula glutinis)为亲本菌株,分别采用聚乙二醇(PEG)和电击方法进行原生质体融合。对得到的融合细胞进行木糖发酵验证,通过检测发酵液中乙醇的含量,筛选出1株产乙醇的重组酵母菌株。利用该重组酵母进行木糖、葡萄糖共发酵,发酵条件为接种量3%,发酵温度27~30 ℃,pH 5.5~6.5,发酵组分为4%木糖、3%蛋白胨、2%酵母浸粉和12%葡萄糖,发酵周期40 h,结果重组酵母可发酵木糖,木糖消耗速率明显低于葡萄糖,乙醇浓度为72 g/L。     

苹果渣固态发酵苹果醋工艺研究

以新鲜苹果渣为主要原料,采用果胶酶法对苹果渣的酒精发酵和醋酸发酵工艺进行优化研究,通过正交试验确定最优酿造工艺参数。初步获得的苹果渣酒精发酵条件是果胶酶添加量0.06%、酵母接种量8%、初始糖度16 °Brix;苹果渣醋酸发酵过程的最优工艺条件是干湿苹果渣的配料比为1 ∶ 10、醋酸菌接种量15%、发酵温度32 ℃,此条件下总酸含量增长到38.267 6 g/L。     

酒糟浸出液发酵产细菌纤维素工艺优化

为了使酿酒废弃物酒糟得以重复利用,降低环境污染,该研究将酒糟作为发酵原料,对木醋杆菌(Acetobacter xy Linum M12)发酵产细菌纤维素进行工艺条件的优化。按照酒糟∶蒸馏水=1∶4 g/g的料液比过滤得到酒糟浸出液,并分析酒糟浸出液成分,以细菌纤维素产量为响应值,从葡萄糖、蛋白胨、酵母粉、柠檬酸、Na2HPO4·12H2O、KH2PO4·3H2O、Mg SO4·7H2O和接种量这8个影响细菌纤维素产量的因素中筛选出显著水平为95%以上的三因素,通过响应面设计对这3个因素进行响应面优化,得出产细菌纤维素数学模型的R2为0.9734,并对数学模型进行了理论分析。研究表明:影响细菌纤维素产量的三因素的影响主次顺序依次为葡萄糖、接种量、柠檬酸,产细菌纤维素的二阶回归模型(P=0.0001)高度显著,决定系数R调整2=0.9392,在此基础上得到的最优的培养基配方为:每1 L酒糟浸出液加入葡萄糖23 g,蛋白胨25 g,酵母粉25 g,柠檬酸4.5 g,Na2HPO4·12H2O 2g,KH2PO4·3H2O 1g,Mg SO4·7H2O 0.2g,接种量8%,发酵温度30°C,培养周期7 d,得到细菌纤维素的预测产量为14.42 g/L。通过验证分析在此条件下细菌纤维素产量为14.44 g/L与预测值(14.42 g/L)吻合度较高,相对误差为0.14%,比优化前(6.0 g/L)提高了140.6%,研究结果为实现酒糟的综合利用提供参考。     

利用甜高粱秸秆汁发酵生产丁醇、丙酮

该试验以甜高粱秸秆汁作为生产丙酮、丁醇的发酵原料,从5种丙酮-丁醇菌中选出能够利用甜高粱秸秆汁且丁醇产量高的Bacillus acetobutylicum Bd3菌作为试验菌株,并对该菌株的发酵条件进行优化,得到的优化条件为:糖度为10oBrix的甜高粱秸秆汁,玉米浆含量5 g/L,接种量6%(v/v),(NH4)2SO4 5 g/L,KH2PO4 0.4 g/L,CaCO3 6 g/L,温度32℃,pH6.8,丁醇产量达到10.29 g/L。     

植物乳杆菌ST-Ⅲ脱脂乳的发酵工艺优化

为研发富含植物乳杆菌ST-Ⅲ新型益生菌发酵乳制品,该试验尝试用植物乳杆菌ST-Ⅲ和嗜热链球菌共发酵,并对植物乳杆菌ST-Ⅲ发酵乳的工艺进行了优化研究。通过单因素试验分析了大豆多肽添加量、葡萄糖酸锰添加量、嗜热链球菌的接种量和发酵温度对发酵乳的pH值和植物乳杆菌ST-Ⅲ活菌数的影响。通过响应面法优化并确定了最佳工艺条件:大豆多肽添加质量分数11 g/kg;葡萄糖酸锰添加质量分数11 mg/kg;嗜热链球菌的接种量106 CFU/g;植物乳杆菌ST-Ⅲ的接种量106 CFU/g;发酵温度为37℃。在此优化最佳工艺条件下,发酵乳的植物乳杆菌ST-Ⅲ的活菌数为1.88×109 CFU/mL,有效地提高了发酵乳中植物乳杆菌ST-Ⅲ的活菌数。研究结果可为拓展植物乳杆菌ST-Ⅲ在乳制品领域的应用提供参考。     

芽孢杆菌组合CL-8发酵条件优化及其防病效能研究（简报）

为了使生防菌Bacillus sp.组合CL-8发酵水平达到最佳效果,为其工业化发酵生产和田间应用提供参考,通过单因素实验和正交实验,确定了Bacillus sp.组合CL-8最佳发酵培养基和最佳发酵条件.最佳发酵培养基为:玉米粉10g/L、豆粕10g/L、蜂蜜5 g/L、氯化钠5g/L、碳酸钠2 g/L、磷酸氧二钾2 g/L、硫酸镁0.2 g/L、碳酸钙1 g/L、硫酸锰0.1 g/L、氯化铁0.1 g/L;最佳发酵条件为:二个单一拮抗菌株Bacillus sp.SL-13、SL-14和SL-44最佳接种比例为2:1:2,培养基初始pH值为7.0.组合CL-8发酵液对加工番茄种子浸种后可提高加工番茄的防病效果,达到55.53%,明显高于三株单一菌浸种后的效果.     

黑曲霉发酵麦麸生产β-葡萄糖苷酶的工艺优化及动力学研究

用单因素和正交试验对黑曲霉M85以小麦麸皮为发酵基质生产β-葡萄糖苷酶的工艺条件进行了优化，并研究了最优发酵条件下的动力学模型。正交试验结果表明，培养基中麦麸的有效添加量为2%，适合摇瓶和5 L罐最佳发酵工艺条件：转速分别为(200±5)r/min和(400±10)r/min，发酵温度均为(30±0.5)℃，接种量分别为15%和10%。黑曲霉M85在摇瓶和5 L罐发酵过程中动力学曲线具有相同的变化趋势，发酵第3 d发酵液中β-葡萄糖苷酶酶活分别达到1103.73 U/mL和1318.82 U/mL，对麦麸的转化率分别为55186.61 U/g和76085.82 U/g。其细胞生长和产物合成可以分别用Monod方程和Luedeking-Piret方程拟合。结果可为麦麸资源生物发酵深加工生产β-葡萄糖苷酶提供技术基础。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.