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1.
米根霉发酵生产L-乳酸   总被引:11,自引:0,他引:11  
报道了L-乳酸菌株的分离与筛选,探讨了不同碳源、氮源、通气量、温度等发酵条件对产L-乳酸的影响,从78株米根霉中筛选出13株产L-乳酸较高的菌株,其中米根霉(Rhizopus oryzae)Rs928产L-乳酸最高,产酸最稳定。试验结果表明,该菌株最适发酵培养组成(%):淀粉水解糖16,MgSO4 0.08,KH2PO4 0.05,ZnSO4 0.01,CaCO3 7,pH自然。在60t发酵罐中,  相似文献   

2.
提高CO2浓度对两种亚热带树苗光合作用的影响   总被引:15,自引:0,他引:15  
鼎湖山季风常绿阔叶林的主要优势乔木树种裂壳锥(Castanopsisfissa (Cham p.ex Benth.) Rehd.etWils.)和荷木(Schim a superba Gardn.etCham p.)幼苗,盆栽于自然条件(CO2 浓度350 μL·L- 1)或高CO2 浓度为500 μL·L- 1和空气CO2(350 μL·L- 1)的半开顶式气罩中。在生长最旺盛的6~9 月份,高浓度CO2 条件下生长的叶片,其光合速率比在自然条件下生长的提高79% ~95% 。当叶片在350 μL·L- 1和500 μL·L- 1的CO2 浓度下测定时,其光合速率无明显差异。高浓度CO2 下生长的叶片其光合速率-CO2 浓度响应曲线比对照(350 μL·L- 1)高,叶绿素和类胡萝卜素含量低,但叶绿素a 和b 的比值及类胡萝卜素和叶绿素的比值不变。高浓度CO2 下生长的叶片气孔导度明显降低。两种植物在85 d 的高浓度CO2 的生长过程中,并未出现光合速率下调现象  相似文献   

3.
土曲霉(Aspergillus terreus)产生洛伐他汀(lovastatin)的研究   总被引:14,自引:0,他引:14  
从土曲霉Aspergillus terreus CA951发酵液中,分离出一种白色针状晶体,经质谱、紫外光谱、红外光 谱和核磁共振谱分析,与文献报道的洛伐他汀(lovastatin)基本一致。 A.terreus  CA951经亚硝基胍诱变,选出 编号为CAN 187的突变株,其产生洛伐他汀的能力比CA951高66%。摇瓶发酵实验研究了不同碳源、氮源和 水质对 CAN187 菌株产生洛伐他汀的影响,并进行了 500L发酵罐实验,发酵单位达900mg/L左右。  相似文献   

4.
对青藏高原高山冰缘地区毛茛科3种特有植物的核型进行了分析。它们的核型公式(K)、染色体相对长度组成(C.R.L.)和核型不对称系数(As.K%)分别为:青藏金莲花Troliuspumilusvar.tanguticus:K(2n)=6m+8sm(2SAT)+2st,C.R.L.=4L+4M2+4M1+4S,As.K%=63.57,核型属2B型;甘青乌头Aconitumtanguticum为K(2n)=6m+10sm,C.R.L.=4L+8M1+4S,As.K%=62.54,2B型;单花翠雀花Delphiniumcandelabrumvar.monanthum为K(2n)=6m+8sm+2st,C.R.L.=4L+4M2+4M1+6S,As.K%=64.34,属3B型。经同相关近缘种核型资料比较,青藏金莲花核型不对称性和进化程度比金莲花T.chinensis低;甘青乌头的核型不对称性和进化程度在其近缘类群(乌头组Sect.Aconitum)已报道的种之内最低;单花翠雀花核型不对称性和进化水平比翠雀组(Sect.Delphinastrum)已报道的展毛翠雀花D.kamaoensevar.glabrescens、  相似文献   

5.
室内恒温条件下以人工饲料饲养的嗜卷书虱Liposcelis bostrychophila Badonnel成虫,分别在0.5%和1%O2组配的气调环境中以7%左右的选择压力处理,以选育其耐低氧气调性。选育至30低氧品系LOC1和LOC2,以LT50为标准其性倍数分别达4.7和3.9倍。整个选育过程中,气调暴露时间对数值与死亡率机率值间的回归直线基本平行,其值均低于敏感基线的斜率值,这表明嗜卷书虱对  相似文献   

6.
在5升发酵罐上对L-Arg和L-Lys作了单级连续培养试验。从嗜醋酸棒杆菌(Corynebacteriumacetoacidophilum)产L-Arg的突变型MC-13的连续培养液中分离出的SC-190菌株能连续超过250小时稳定地产L-Arg达60g/L。用谷氨酸棒杆菌(Corynebacteriumglutamicum)产L-Lys突变株B-6进行连续培养,可稳定维持500小时之久。连续培养产L-Lys·HCl浓度达105g/L,体积产率为5.6g/L/h,是流加培养的2.5倍。产率提高依赖于氧气的供应,实验表明连续培养是分离适于连续培养菌株和提高产率的有效手段。  相似文献   

7.
浙江凤仙花属新分类群   总被引:3,自引:0,他引:3  
1九龙山凤仙花新种图1ImpatiensjiulongshanicaY.L.XuetY.L.Chen,sp.nov.Fig.1SpecieshabituetformafoliorumI.chekiangensiY.L.Chenvaldesimilis...  相似文献   

8.
西藏佩枯错距今13000—45000年间的介形类及环境变迁   总被引:13,自引:0,他引:13  
西藏西南部佩估错的三级价地剖面产有壳体数量较大的介形类运动群,但属种相对单调,计有5属14种,分别为Leucocythere mieabilis,L.dorsotuberosa,L.subsculpta,L.sp.1,L.sp.2,Leucocytherella sinensis,L.cf,sinensis,L.biechinata,L.trindoa,Candona xizangensis,C.  相似文献   

9.
阳军  孙华保 《蛇志》1998,10(4):17-19
目的观察辛伐他丁对冠心病高血脂症患者血清脂质的影响。方法冠心病高血脂症病人50例,均有血脂(TC、TG、HDL-C、LDL-C或4项中任何一项)异常。服用辛伐他丁,5~20mg,每日1次,晚间顿服,疗程8周。服药前后晨起空腹查血脂以作自身对照。结果对高TC下降有效率达91.5%,对高LDL-C下降有效率达82.5%,对高TG下降有效率达76.2%,对低HDL-C增高有效率为72.2%。其中对TC、LDL-C治疗8周有极显著意义(P<0.01),,对TG下降、HDL-C升高8周后有显著意义(P<0.05)。治疗期间不良反应轻微。结论辛伐他丁可作为冠心病患者减少CHD事件发病率及住院率的理想药物。  相似文献   

10.
浙江鸭跖草属植物的核型研究   总被引:1,自引:0,他引:1  
王丰  金锦萍  王庆红  方益华   《广西植物》1994,14(4):354-356
本文报道了浙江二种鸭跖草属植物──饭包草CommelinabengalensisL.和鸭跖草CommelinacommunisL.的染色体数目与核型:CommelinabengalensisL.核型为K(2n)=22=18m+4smCommelinacommunisL.核型为K(2n)=22=4M+12m+4sm+2st  相似文献   

11.
产油真菌在甘薯淀粉废水中发酵的初步研究   总被引:1,自引:0,他引:1  
目的:利用甘薯淀粉废水发酵低成本获取微生物油脂。方法:以甘薯淀粉废水为发酵基质,进行菌株筛选、发酵工艺优化及油脂成分的气相色谱分析。结果:筛选出一株刺孢小克银汉霉F7,生物量为19.375g/L,含油量为45.1%。菌株F7发酵第11天生物量达到18.140g/L,含油量达到51.2%,COD去除率87%。研究发现与对照相比,NaAc和KH2PO4对生长、产油以及出水COD去除有显著促进作用,NaAc2g/L时生物量提高了25.4%,含油量提高了4.4%,COD下降了52.0%,KH2PO4的作用稍次之。结论:资源化利用甘薯淀粉废水发酵生产微生物油脂同时降低废水COD是一条可行的途径,可以为生物柴油提供廉价油源。  相似文献   

12.
An eco-friendly and cost effective technique- phytoremediation was used to remediate contaminants from waste water. This study demonstrated that phytoremediation ability of duckweed (Lemna minor L.) to remove chloride, sulphate from Biological Oxygen Treatment (BOT) waste water of coke oven plant. The BOT water quality was assessed by analyzing physico-biochemical characters – pH, Biological oxygen demand (BOD), Chemical oxygen demand (COD), total dissolved solids (TDS) and elemental concentration. It was observed that an increase in pH value indicated an improvement of water quality. The experimental results showed that, duckweed effectively removed 30% chloride, 16% sulphate and 14% TDS from BOT waste water, which suggested its ability in phytoremediation for removal of chloride and sulphate from BOT waste water. A maximum increase of 30% relative growth rate of duckweed was achieved after 21 days of experiment. Thus, it was concluded that duckweed, an aquatic plant, can be considered for treatment of the effluent discharged from the coke oven plant.  相似文献   

13.
Conjugation in starforming Rhizobium lupini   总被引:9,自引:0,他引:9  
Summary ARhizobium strain which exhibits high efficiency of starformation has been isolated from the root nodules ofLupinus luteus. Mutants of this strain were induced by repeated treatment of the wild type with nitrous acid. The mutants are marked with one or two auxotrophic characters and with different colors (carotenoid production). Two-, three-, and four-point crosses were performed. The maximum recombination rate is around 10%. A quantitative evaluation of the results of the crosses indicates the existence of a circular linkage map.The recombination is the result of a conjugation between cells during which most probably always the whole chromosome is transferred.The research was supported by NSF Grant. No. GB-4287 and NJH Grant No. 1 PO 1 GM 13234.  相似文献   

14.
A medium based on less expensive nutrient sources, such as corn starch hydrolyzate (hydrol), corn steep liquor (CSL), urea and potassium phosphate was used for the growth of the yeast Phaffia rhodozyma 2A2N strain. A central composite experimental design has been employed to derive a statistical model on the effect of hydrol and CSL on carotenoid production. An initial concentration of sugars as glucose equivalent 73?g/l in hydrol and 43?g/l CSL were found optimal for the maximization of final carotenoid production in shake flask cultures. The carotenoid production was increased by adding urea and phosphate sources. Laboratory scale fermentation was performed with the optimized medium and total carotenoid production of 52.4?mg/l was obtained using constant fed-batch culture.  相似文献   

15.
Jin B  Huang LP  Lant P 《Biotechnology letters》2003,25(23):1983-1987
Rhizopus arrhizus, strain DAR 36017, produced L(+)-lactic acid in a simultaneous saccharification and fermentation process using starch waste effluents. Lactic acid at 19.5-44.3 g l(-1) with a yield of 0.85-0.96 g g(-1) was produced in 40 h using 20-60 g starch l(-1). Supplementation of nitrogen source may be unnecessary if potato or corn starch waste effluent was used as a production medium.  相似文献   

16.
激光诱变青霉PT95原生质体选育类胡萝卜素高产菌株   总被引:5,自引:0,他引:5  
采用激光对青霉PT95菌株的原生质体进行了诱变处理,选育到一株菌核生物量和类胡萝卜素含量均有显提高的突变菌株L05。与出发菌株相比,L05菌株的菌核生物量提高了98.6%,菌核中的类胡萝卜素含量提高了28.3%,在查氏平板上的类胡萝卜素产率提高了154.0%。所选育的L05菌株经3次传代培养,菌落没有发生扇形变异,菌核生物量和类胡萝卜素含量没有明显改变,说明该菌株具有良好的遗传稳定性。  相似文献   

17.
目的从土壤中分离产淀粉酶相对较高的菌株,并对其产酶条件进行优化,以期获得更经济、易得的高活力淀粉酶。方法用平板稀释涂布法分别从温州及其周边地区多个淀粉含量高的土壤、污水中采集的样品中筛选产淀粉酶菌株,通过菌落形态、生理生化反应和16S rDNA序列比对对菌株进行鉴定;并从碳源、氮源、离子浓度及紫外诱变等产酶条件对高产淀粉酶菌株进行优化;利用碘-淀粉法等对粗酶液酶学性质进行初步研究。结果从采集到的26个样品中共筛选到19株酶活较高、产酶稳定的野生型菌株。其中编号为Z19的菌株酶活最高,达到351.78 U/mL。经形态和生理生化鉴定,结合16S rDNA序列分析,将该菌株鉴定为解淀粉芽胞杆菌。对菌株Z19的液体发酵条件研究表明,最佳条件为玉米粉1.0%,明胶1.5%,淀粉含量0.5%,NaCl 0.5%,pH7.0,发酵温度37℃,72 h,酶活达到1 360.92 U/mL;在固体培养基上,直接用麸皮,接种量为0.1%,含水量为60%,pH7.0,120 h时,酶活达到1 504.2 U/mL。其最适酶反应pH为6.5,反应温度55~60℃,底物浓度为0.5%。结论从土壤中分离得到了产淀粉酶相对较高的解淀粉芽胞杆菌Z19菌株,产酶条件适用于工业生产,具有一定的应用前景。  相似文献   

18.
Summary A clump-forming bacterial strain was isolated from a sludge community derived from a waste water treatment plant. The Gram-negative bacterium is hydrophobic and forms an extensive capsule while clumping in dilute medium (0.1% bacto peptone). Emulsan, a capsule inhibitor, does not affect the clumping ability of this bacterium. Clumps are not dispersed with high and low pH, detergents or chelators. Bacterial clumping selected by the waste water treatment processes appears to be a complex set of interactions within and between the strains of bacteria. This study reveals some of the complexities.  相似文献   

19.
Biological treatment of industrial waste is a widely practiced technique that generates comparatively less environmentally hazardous waste than other chemical treatment processes. Wet milling of maize generates huge amount of wastewater (5 m3/ton) of low pH with organic matter and nutrients. Anaerobic methanogenic and aerobic bacteria are mostly highly sensitive to low pH. The treatment of wastewater causes huge cost of chemical neutralization or hydraulic recirculation for maintaining neutral pH. In the present study, different microbial consortia isolated from cow dung, active sludge from an anaerobic reactor for treatment of industrial wastewater, and leaf debris from benthic soil were screened for tolerance against low pH and for potential of chemical oxygen demand (COD) removal in order to find out an alternative microbial population for industrial water treatment at low pH. The most effective consortia found from leaf debris were further investigated for optimal operation. The microscopic analysis of leaf debris sludge showed abundance of Gram‐negative methanococci, which was found tolerant to low pH in plate culture method. On further investigation for COD removal from starch industry effluent, they were found to be most effective at pH 5 with highest COD removal rate of 70% and lowest biomass generation of 81%. Hence, it was concluded that the low pH‐tolerant methanogen bacteria, enriched from leaf debris sludge, is highly beneficial for anaerobic treatment of wastewater from several industries including corn starch industry by reducing cost of operation for neutralization to neutral pH and through reducing excess waste sludge production by the treatment system.  相似文献   

20.
Moderately halotolerant selenate- and tellurite-reducing bacteria were characterized for wastewater treatment applications. A selenate-reducing strain 9a was isolated from the biofilm of a leachate treatment plant at a sea-based waste disposal site. A tellurite-reducing strain Taa was isolated from an enrichment culture derived from brackish sediment. Both bacterial strains were Shewanella species. Strain 9a could anaerobically remove 45–70% of 1.0 mM selenate and selenite from water containing up to 3% NaCl within 4 days, while strain Taa could anaerobically and aerobically remove 70–90% of 0.4 mM tellurite from water containing up to 6% NaCl within 3 days. Globular particles of insoluble selenium were observed both outside and inside the cells of strain 9a. The insoluble tellurium formed by strain Taa was globular under microaerobic conditions but nanorod under aerobic conditions. These bacteria will yield a range of useful selenium and tellurium nanomaterials as well as wastewater treatment applications.  相似文献   

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