固定化微生物菌剂与蕹菜对中华鳖养殖污水的净化效果研究

为解决中华鳖(Trionyx sinensis)养殖所造成的水环境污染问题,研究利用海藻酸钠、沸石对复合光合菌剂和枯草芽孢杆菌菌剂分别进行固定化,并研究了不同固定化微生物菌剂与蕹菜对中华鳖养殖污水的净化效果。结果表明:净化处理15d后,利用固定化微生物菌剂与蕹菜共同处理组对中华鳖养殖污水的净化处理效果最好,养殖污水的CODMn、NH 4+-N、NO3-N、NO 2-N、PO34的去除率分别为88.7%、87.3%、90.8%、98.3%、74.9%。蕹菜处理组对于NO3-N、NO 2-N、NH 4+-N的去除率显著高于固定化复合光合菌剂处理组和固定化枯草芽孢杆菌处理组。固定化复合光合菌剂处理组对于NO3-N、NO 2-N、NH 4+-N的去除率显著高于固定化枯草芽孢杆菌菌剂处理组,但固定化枯草芽孢杆菌处理组对于污水的CODMn的去除率最高,可达90.6%。     

根际微生物组介导的解淀粉芽孢杆菌FH-1对水稻的促生机制

【目的】利用大田实验和分子生物学技术进行水稻促生菌解淀粉芽孢杆菌(Bacillus amyloliquefaciens) FH-1改良土壤微生物组的研究,以初步了解解淀粉芽孢杆菌FH-1的促生机理,为微生物肥料的研制和应用提供理论基础。【方法】设置菌剂FH-1处理(FH)和空白对照(CK)的水稻大田实验,测定植物生理性状包括水稻株高、根长和穗长,并统计水稻的穗数、单穗粒数和千粒重;利用实时荧光定量PCR技术分析水稻根际土壤细菌的数量;利用16SrRNA基因高通量测序解析水稻根际土壤微生物的物种组成;进一步通过Pearson相关统计分析研究水稻-土壤-微生物之间的相互作用。【结果】与空白对照(CK)相比,菌剂FH-1处理(FH)中植物的株高、根长、穗长、单株穗数、单穗粒数、千粒重显著提高,但是土壤理化性质无显著性差异。菌剂FH-1处理(FH)对细菌总数量无显著影响,但是可显著降低微生物α多样性,显著提高土壤中的γ-变形菌纲、绿弯菌门,显著降低土壤中的β-变形菌纲、疣微菌门的丰度(P0.05),LEfSe分析显示菌剂FH-1处理(FH)土壤中富集的微生物有19个,主要包括绿弯菌门、PAUC34f、S035、4-29、芽孢杆菌纲、芽孢杆菌目、浮霉菌纲、A31、H39、S0208、Gemmatales、红螺菌目、HOC36、AKIW659、0319-6A21、生丝微菌科、红螺菌科、EB1003、HB2-32-21。相关性分析结果表明施加菌剂FH-1及其富集的相关物种与水稻植株的各个特性呈正相关。【结论】在水稻大田种植中施加微生物菌剂FH-1,可显著促进水稻生长,对土壤理化性质无显著影响,但可以显著改变微生物群落结构和功能,富集有益物种。因此我们推测解淀粉芽孢杆菌FH-1是通过调控根际微生物群落结构和功能促进水稻生长和发育。     

水稻秸秆腐解复合菌系RSS-4的选育及其腐解特性

采用限制性培养技术与温度梯度诱导相结合的方法, 从四川成都平原多年还田的土壤中筛选、构建出一组在中温条件下对水稻秸秆具有腐解功能的复合菌系RSS-4。该复合菌系在22°C条件下, 稻秆腐解试验表明: pH先升高后降低, 最后稳定在7.20; 纤维素酶活、半纤维素酶活均经历了先升后降的变化趋势, 最高酶活分别为0.91、3.40 U; 到16 d腐解结束时, RSS-4对稻秆、纤维素及半纤维素的降解率分别达到了45.0%、55.5%和44.1%, 而木质素在整个腐解过程中未发生明显的变化; 说明所筛选构建的这组腐解复合菌系可加速稻秆的腐解。同时发现采用未灭菌的筛选方法筛得的复合菌系RSS-4比灭菌所得的RSS-4￠腐解效果要好。     

饲用微生物的分离鉴定及其对杏鲍菇菌糠发酵的效果

【目的】菌糠的营养素含量齐全,但纤维素含量过高是阻碍其饲料化利用的主要因素。故本研究筛选适合于发酵杏鲍菇菌糠的微生物菌株,以改善其饲用品质。【方法】首先,本研究采用纤维素-刚果红、苯胺蓝和MRS-Ca (De Man, Rogosa, Sharpe-Ca)筛选培养基,结合纤维素、木质素酶活力及抑菌活性的测定,从EM (effective microorganisms)原液发酵的杏鲍菇菌糠中分离筛选具有较强纤维素、木质素降解能力及抑菌能力的细菌/真菌。通过细菌16S rRNA和真菌18S rDNA基因序列分析确定菌株所属种属。其次,将筛选出的菌株菌液等体积混合制成复合菌剂用于固态发酵杏鲍菇菌糠。测定不同发酵时长菌糠营养成分含量以确定最佳发酵时间,并与相同工艺条件下EM原液发酵的杏鲍菇菌糠进行饲用品质比较。【结果】筛选并鉴定得到纤维素酶活性较高的特基拉芽孢杆菌(Bacillus tequilensis)菌株P11、发酵毕赤酵母(Pichia fermentans)菌株R8和马克斯克鲁维应变酵母(Kluyveromyces marxianus)菌株MU5;木质素酶活性较高的解淀粉芽孢杆菌(Bacillus amyloliquefaciens subsp.plantarum)菌株MU7;抑菌活性较高的类肠膜魏斯氏菌(Weissella paramesenteroides)菌株R4和乳酸片球菌(Pediococcus acidilactici)菌株R9。使用以上菌株复合发酵杏鲍菇菌糠7 d后,各项指标达到稳定。与EM原液发酵的杏鲍菇菌糠相比,复合菌剂发酵杏鲍菇菌糠的NDF和ADF分别显著降低了19.6%和21.44%(P0.05);CP (crude protein)、CA (crude ash)和EE (ether extract)含量分别显著提高了10.44%、5.26%和123.53%(P0.05)。【结论】本研究筛选得到的芽孢杆菌、酵母菌和乳酸菌优势菌株复合后用于发酵杏鲍菇菌糠可以很好地改善其饲用品质,效果优于生产中常用市售EM原液。     

一件出土饱水木漆器文物中可培养细菌的鉴定及对木材的腐蚀作用

【背景】饱水木质文物易受到微生物侵害,目前国外围绕饱水木质文物微生物病害已开展多方面研究,并取得阶段性进展,而国内在饱水木质文物微生物学技术方面的报道比较少。【目的】研究保藏水环境中出土饱水木漆器F446及水中细菌的种类,以及对木材的腐蚀作用。【方法】采用16S rRNA基因序列分析方法及生理生化试验,对饱水木漆器F446及水环境中细菌进行鉴定,并选取典型菌按5×10~8个/瓶菌量接种马尾松心材(悬于无菌自来水中),37°C培养120 d,测试木材的损失率。【结果】从F446文物和水样中分离的53株细菌中,21株被鉴定为芽孢杆菌属(Bacillus),为优势菌属,其中蜡样芽孢杆菌(B.cereus)19株,病研所芽孢杆菌(B.idriensis)和苏云金芽孢杆菌(B.thuringiensis)各1株;11株菌被鉴定为短杆菌属(Brevibacterium),此外还有4株短波单孢菌属(Brevundimonas),5株粪产碱杆菌(Alcaligenes faecalis),5株Altererythrobacter,2株水氏黄杆菌(Flavobacterium mizutaii);另外,还有解糖假苍白杆菌(Pseudochrobactrum saccharolyticum)、梭型芽孢杆菌(Lysinibacillus fusiformis)、Leucobacter aridicollis、Ochrobactrum pseudogrignonense、类芽孢杆菌属(Paenibacillus)菌株各1株。菌株A5、A6分别为类芽孢杆菌(Paenibacillus)和Altererythrobacter属中的疑似新种。从典型菌中选取15株菌回接木材进行腐蚀试验,结果显示,9株细菌与对照组比较存在极显著差异,说明这些菌对马尾松木材有一定的腐蚀作用,但是腐蚀率非常低,最高仅1.38%,表明这些细菌对试验木材马尾松腐蚀并不严重。【结论】F446木漆器文物样品中优势菌属为芽孢杆菌属(Bacillus),水样中优势菌属依次为短杆菌属(Brevibacterium)、短波单孢菌属(Brevundimonas)和Altererythrobacter。从F446木漆器文物和水样中分离出的细菌对木材的降解非常缓慢,短期内腐蚀作用有限。     

茄子黄萎病菌抗性根际芽孢杆菌的筛选与鉴定

利用离体抑菌圈法从茄子根际土壤筛选出8株对黄萎病菌大丽轮枝菌(Verticillium dahliae)抑菌效果明显的芽孢杆菌,其中F53菌株分泌几丁质酶和-β1,3-葡聚糖酶,对所检测的12种植物病原菌具明显的抑制作用,其发酵液热、酸碱稳定性强,用F53菌株制成的菌剂对茄子黄萎病盆栽试验防效为52.4%~75.8%,初步鉴定F53菌株为环状芽孢杆菌(Bacillus circulans)。     

片烟产果胶酶细菌的鉴定及酶活测定

以果胶为碳源, 对津巴布韦片烟烟叶表面产果胶酶细菌进行分离, 采用16S rDNA限制性酶切片段长度多态性分析(ARDRA)和测序方法, 结合形态学、生理生化实验, 对所分离产果胶酶菌株进行鉴定, 同时研究培养时间、温度、起始pH、接种量对菌株产酶的影响。结果表明, 从津巴布韦片烟烟叶表面分离得到的产果胶酶菌株主要为芽孢杆菌属的枯草芽孢杆菌Bacillus subtilis和产碱菌属的粪产碱菌Alcaligenes faecalis。在所分离的菌株中, 枯草芽孢杆菌T10酶活力最高, 以6%的接种量, 在温度为35 °C、起始pH为7.5条件下培养48?56 h, 其果胶酶酶活为571 U/mg, 聚半乳糖醛酸裂解酶酶活为297 U/mg。     

复合菌系RSS-4传代对水稻秸秆腐解的影响

对筛选到的1组稻秆腐解复合菌系RSS-4,以腐解产物的pH值、酶活及稻秆失重率为指标,研究了该复合菌系的性质稳定性和功能稳定性;并用变性梯度凝胶电泳法(DGGE)分析了该复合菌系的菌种组成稳定性。结果表明,多代继代培养过程中各代复合菌系腐解产物的pH值变化趋势基本一致,pH值从起始的6.72左右迅速升至最高点7.75,然后逐渐下降并稳定在7.20;多代继代培养后复合菌系各代之间的酶活动态变化及其对稻秆腐解能力的差异均很小。在连续继代培养的过程中,DGGE图谱揭示第15~23代复合菌系之间的菌种组成没有明显差异。     

粪产碱杆菌青霉素G酰化酶在枯草芽孢杆菌中的表达、纯化及其性质

利用PCR技术克隆了粪产碱杆菌 (Alcaligenesfaecalis,CICCAS1.76 7)青霉素G酰化酶 (pencillinGacylase ,PGA)基因 (GenBank登录号AF4 5 5 35 6 )。通过构建工程菌E .coli(pETAPGA) ,该酶在大肠杆菌中获得了表达 ,表达产物分泌到周质空间。进一步构建的工程菌B .subtilis (pMAPGA)和B .subtilis(pBAPGA)实现了该酶的胞外分泌表达。分泌表达的最高表达量为 6 5 3u/L ,比野生型A .faecalis表达量高 10 9倍。表达产物经硫酸铵分级沉淀和DEAE SepharoseCL 6B两步纯化 ,纯度提高 86倍 ,活力回收率达到 81% ,纯化后的PGA活力为 1.4 6 9u/mg。研究表明 ,PGA家族成员中只有粪产碱杆菌PGA和巨大芽孢杆菌PGA可以在枯草芽孢杆菌中分泌表达。与巨大芽孢杆菌PGA相比 ,粪产碱杆菌PGA的最适pH值为 8.0 ,最适温度为 6 0°C ,而且在有机溶剂中具有更强的稳定性。该酶在水相中具有较低的头孢氨苄合成活力。本研究为粪产碱杆菌PGA的获得提供了新的途径。     

应用16S rDNA克隆文库法分析有机物料腐熟菌剂细菌组成

应用16SrDNA克隆文库法对有机物料腐熟菌剂A和B样品中的细菌组成进行分析研究。结果表明,样品A有14个OTU,主要是融合乳杆菌(Weissella confusa)、枯草芽孢杆菌(Bacillus subtilis)和短小芽孢杆菌(Bacillus pumilus),其比例分别占总克隆文库的28.6%、30.4%和23.2%;样品B有43个OTU,主要是布氏乳杆菌(Lactobacillus buchneri)、香肠乳杆菌(Lactobacillus farciminis)和耐酸乳杆菌(Lactobacillus acetotolerans),占总克隆文库的比例分别为18.03%、18.86%和13.12%;所得出的结果均与产品标注存在差异,样品A未提及细菌的种类,而样品B只标注短小芽孢杆菌。研究表明这一方法在微生物菌剂细菌组成分析及其质量检测中具有良好的应用前景。     

玉米秸秆和异Vc钠生产废液固态发酵生产高蛋白饲料研究

以玉米秸秆为原料,以麸皮和异Vc钠生产废液(WEP)为辅料进行生物蛋白饲料固态发酵研究.通过菌种配伍试验,确定了混菌发酵菌种为白地霉、产朊假丝酵母和枯草芽孢杆菌.在此基础上通过单因素优化试验确定了秸秆蛋白饲料的最优发酵条件:以玉米秸秆(5 g)和麸皮(1 g)为基料,4%WEP营养液,固液比1:4(g/mL),初始pH值4.5;以麸皮浸汁作种子培养液,种龄24 h,各菌接种比例为产朊假丝酵母∶白地霉∶枯草芽孢杆菌=3:1:1,接种量2 mL;28℃、静置发酵2 d,在此条件下,秸秆饲料中真蛋白含量为6.21%,比对照提高了23.95%.该研究为秸秆和异Vc钠生产废液的高质化利用提供了新的思路和途径.     

Production of Xylanase of Bacillus coagulans and its bleaching potential

Summary The production of xylanase from Bacillus coagulans has been studied with respect to the environmental parameters, the carbon source and the concentration of carbon source at the shake flask level. Among the various carbon sources used, wheat straw powder favoured higher enzyme production. Xylan isolated from wheat straw gave higher enzyme production as compared to the birchwood xylan. Maximum enzyme activity of 165 IU/ml was obtained with 2% wheat straw xylan in a shake flask study. Improvement of xylanase production was achieved by increasing the wheat straw powder concentration up to 3%. Enzyme has optimum activity at a temperature of 55 °C and pH of 7. The concentrated crude enzyme was found to reduce the kappa number of enzyme-treated eucalyptus pulp by␣5.45% with a marginal increase in the CED viscosity of the enzyme treated pulp as compared to the non-enzymatically treated pulp.     

产木聚糖酶芽胞菌Y-12的筛选及产酶条件的研究

利用透明圈平板培养和木聚糖发酵试验,筛选出1株高产木聚糖酶的芽胞杆菌,并对该菌株的酶学特性和适宜发酵条件进行研究。结果表明,此菌对秸秆和麦麸的分解率分别为43.3%和63.4%。产酶较高的最适培养条件,即大豆蛋白胨2%、胰蛋白胨3%、酵母粉0.1%和葡萄糖2%。适宜反应温度和pH分别为37℃和7。采用10 L发酵罐发酵,培养48 h后,酶活达3024 U/m l,比三角瓶发酵(酶活达2185 U/m l)提高了38%。     

Solid-state anaerobic digestion of spent wheat straw from horse stall

The spent wheat straw from horse stall bedding has lower cellulose and hemicellulose contents, but higher volatile fatty acid content than raw wheat straw. Biogas production from solid-state anaerobic digestion (SS-AD) of spent wheat straw and raw wheat straw was compared in this study. The SS-AD tests were conducted at 22% total solids (TS) content using inoculum from a liquid AD system at three feedstock-to-inoculum (F/I) ratios of 2.0, 4.0, and 6.0. Daily methane yields of spent wheat straw peaked 8 and 3 days earlier than those of raw wheat straw at F/I ratios of 2.0 and 4.0, respectively. The highest methane yield of 150.0 L/kg volatile solids (VS) was obtained from spent wheat straw at an F/I ratio of 4.0, which was 56.2% higher than that of raw wheat straw. The corresponding cellulose and hemicellulose degradation of spent wheat straw was 24.1% and 49.4% higher than those of raw wheat straw, respectively.     

Improving enzymatic hydrolysis of wheat straw using ionic liquid 1-ethyl-3-methyl imidazolium diethyl phosphate pretreatment

This study aims to establish a cellulose pretreatment process using ionic liquids (ILs) for efficient enzymatic hydrolysis. The IL 1-ethyl-3-methyl imidazolium diethyl phosphate ([EMIM]DEP) was selected in view of its low viscous and the potential of accelerating enzymatic hydrolysis, and it could be recyclable. The yield of reducing sugars from wheat straw pretreated with this IL at 130 °C for 30 min reached 54.8% after being enzymatically hydrolyzed for 12 h. Wheat straw regenerated were hydrolyzed more easily than that treated with water. The fermentability of the hydrolyzates, obtained after enzymatic saccharification of the regenerated wheat straw, was evaluated using Saccharomyces cerevisiae. This microbe could ferment glucose efficiently, and the ethanol production was 0.43 g/g glucose within 26 h. In conclusion, the IL [EMIM]DEP shows promise as pretreatment solvent for wheat straw, although its cost should be reduced and in-depth exploration of this subject is needed.     

Effects of wheat straw particle size as a free-choice provision on growth performance and feeding behaviors of dairy calves

In the dairy calf feeding, supplementation of forage to the starter feed is commonly practiced. However, data are insufficient about how changes in particle size (PS) of forage affect calf performance and behavior in a free-choice forage provision system. This study aimed to assess the effects of supplementing wheat straw varying in PS on performance, skeletal growth characteristics, ruminal pH, nutritional behaviors, and blood metabolites of dairy calves. Forty-eight Holstein calves (43.8 ± 3.2 kg of BW) from d 15 of age were randomly assigned to one of the four treatments (n = 12/treatment; six males and six females): (1) starter without wheat straw supplementation (CON), (2) CON supplemented with wheat straw chopped at 1 mm geometrical mean particle length (GMPL) (fine PS), (3) CON supplemented with wheat straw at 4 mm GMPL (medium PS), and (4) CON supplemented with wheat straw at 7 mm GMPL (long PS). The calves were given ad libitum access to feed and water throughout the study. All calves were weaned on d 56 of age and continued the experiment until d 90. The starter, wheat straw, and total solid feed intakes were not affected by GMPL of wheat straw; however, CON calves had a lower solid feed-, total DM- and NDF-intake than calves offered wheat straw. Further, ADG, weaning, and final BWs as well as feed efficiency were similar between treatments. No difference was observed in growth rate of hip height, hip width, body barrel, wither height, and heart girth among treatments, however, wheat straw supplemented calves tended to have greater body length at weaning. Blood concentration of serum β-hydroxy butyrate was greater in wheat straw supplemented calves compared with CON calves on d 56 and 90. Calves supplemented with wheat straw spent more time eating starter and forage, lying and ruminating and less time for standing and non-nutritional behaviors compared with the CON calves on d 49 and 63 of the study. Moreover, calves offered wheat straw had greater ruminal pH than CON calves at 4 and 8 h after offering starter feed on d 35. In conclusion, supplementing wheat straw as a free-choice increased solid feed intake, rumen pH, and calves' welfare, however, PS of wheat straw had no effect.     

Operating conditions of a 200l staged vertical reactor for bioconversion of wheat straw by Phanerochaete chrysosporium

Bioconversion of wheat straw using Phanerochaete chrysosporium was carried out in a 200l staged vertical reactor. The bioconversion process was characterized by measuring the percentage degradation of lignin and cellulose, and increment in crude protein content. The effect of airflow rate, inoculum amount and wheat straw loading on bioconversion was investigated using a statistical experimental design. An analysis of variance was performed to determine response surfaces. The quality of bioconversion indicated by an optimization index called the desirability coefficient had the highest value of 0.75 for the fifth day of cultivation. This corresponded to an operating condition of 1.5kg wheat straw per stage using an inoculum amount of 0.38g (100g dry wheat straw)(-1) and an airflow rate of 15lmin(-1). The lignin and cellulose degradation achieved at this operating condition was 27% and 29%, respectively. A ratio of 3 for the weight of wheat straw to inoculum amount gave the highest crude protein of 5.9% on dry weight basis. Among the variables investigated, the airflow rate exhibited a significant effect on the quality of bioconversion. Our results indicate that the quality of bioconversion may be controlled by implementing a predetermined airflow rate schedule.     

Effect and aftereffect of gamma radiation pretreatment on enzymatic hydrolysis of wheat straw

Irradiation pretreatment of wheat straw was carried out at different doses by using Co-60 gamma radiation. The weight loss and fragility of wheat straw after irradiation, the combination effect of irradiation and mechanical crushing on enzymatic hydrolysis of wheat straw as well as the aftereffect of irradiation were examined. It is shown that irradiation can cause significant breakdown of the structure of wheat straw. The weight loss of wheat straw increased and the size distribution after crushing moved to fine particles at elevated irradiation doses. The glucose yield of enzymatic hydrolysis of wheat straw increased with increasing doses and achieved the maximum (13.40%) at 500 kGy. A synergistic effect between irradiation and crushing was observed, with a glucose yield of 10.24% at a dose of 500 kGy with powder of 140 mesh. The aftereffect of irradiation had important impact on enzymatic hydrolysis of wheat straw. The aftereffect (at 22nd day) of 400 kGy irradiation accounted for 20.0% of the initial effect for glucose production, and the aftereffects of 50, 100, 200 (at 9th day) and 300 kGy (at 20th day) accounted for 12.9%, 14.9%, 8.9% and 9.1%, respectively, for reducing sugar production.     

Genetic variability in arbuscular mycorrhizal fungi compatibility supports the selection of durum wheat genotypes for enhancing soil ecological services and cropping systems in Canada

Crop nutrient- and water-use efficiency could be improved by using crop varieties highly compatible with arbuscular mycorrhizal fungi (AMF). Two greenhouse experiments demonstrated the presence of genetic variability for this trait in modern durum wheat ( Triticum turgidum L. var. durum Desf.) germplasm. Among the five cultivars tested, 'AC Morse' had consistently low levels of AM root colonization and DT710 had consistently high levels of AM root colonization, whereas 'Commander', which had the highest colonization levels under low soil fertility conditions, developed poor colonization levels under medium fertility level. The presence of genetic variability in durum wheat compatibility with AMF was further evidenced by significant genotype × inoculation interaction effects in grain and straw biomass production; grain P, straw P, and straw K concentrations under medium soil fertility level; and straw K and grain Fe concentrations at low soil fertility. Mycorrhizal dependency was an undesirable trait of 'Mongibello', which showed poor growth and nutrient balance in the absence of AMF. An AMF-mediated reduction in grain Cd under low soil fertility indicated that breeding durum wheat for compatibility with AMF could help reduce grain Cd concentration in durum wheat. Durum wheat genotypes should be selected for compatibility with AMF rather than for mycorrhizal dependency.     

Fractionation of wheat straw by atmospheric acetic acid process

Fractionation of wheat straw was investigated using an atmospheric acetic acid process. Under the typical conditions of 90% (v/v) aqueous AcOH, 4% H(2)SO(4) (w/w, on straw), ratio of liquor to straw (L/S) 10 (v/w), pulping temperature 105 degrees C, and pulping time 3h, wheat straw was fractionated to pulp (cellulose), lignin and monosaccharides mainly from hemicellulose with yields of approximately 50%, 15% and 35%, respectively. Acetic acid pulp from the straw had an acceptable strength for paper and could be bleached to a high brightness over 85% with a short bleaching sequence. Acetic acid pulp was also a potential feedstock for fuels and chemicals. The acetic acid process separated pentose and hexose in wheat straw to a large extent. Most of the pentose (xylan) was dissolved, whereas the hexose (glucan) remained in the pulp. Approximately 30% of carbohydrates in wheat straw were hydrolyzed to monosaccharides during acetic acid pulping, of which xylose accounted for 70% and glucose for 12%. The acetic acid lignin from wheat straw showed relatively lower molecular weight and fusibility, which made the lignin a promising raw material for many products, such as adhesive and molded products.