不同氮/碳源组合条件下斜生栅藻的生长、光合及油脂产率

以斜生栅藻为研究材料,选取NaNO3、NaNO2、NH4Cl、尿素（CO(NH2)2）作为氮源,Na2CO3、C6H12O和CH3COONa作为碳源,进行两两组合培养,研究不同氮源、碳源组合条件对斜生栅藻生长、最大光量子产率（Fv/Fm）、油脂产率及脂肪酸组成的影响。结果表明：CO(NH2)2作为氮源时,斜生栅藻生物量、叶绿素a含量及Fv/Fm均达到最高,而NH4Cl不利于斜生栅藻的生长。在NaNO3、NaNO2和NH4Cl为氮源时,3种碳源对斜生栅藻生长的影响差异不显著（P>0.05）,而在CO(NH2)2环境中,Na2CO3的添加使得斜生栅藻生物量显著高于其他两组（P<0.05）,说明CO(NH2)2和Na2CO3组合更有利于斜生栅藻的生长。12组处理中,N1（CO(NH2)2+Na2CO3）和Y2（NaNO2+C6H12O）油脂产率最高,分别占细胞干重的23.14%和21.54%,同时藻油中油酸相对含量分别为57.92%和57.81%。因此,无论是生物量的积累还是油脂产率,CO(NH2)2作为氮源且Na2CO3作为碳源具有一定的应用前景。     

户外环境条件下三角褐指藻生长和积累脂肪酸的条件优化

微藻的脂肪酸含量与其应用价值有直接关系,而环境因素对微藻脂肪酸含量有着显著影响。本文以细胞密度、干重浓度、脂肪酸含量等为评价指标,研究了户外跑道池系统中不同盐度(20‰、25‰和30‰)、p H值(7.5、8.0和8.5)、氮源种类(尿素和碳酸氢铵)等环境因素下三角褐指藻户外生长、脂肪酸积累的规律。结果表明,随着培养基盐度的升高,三角褐指藻的增长速率变缓,在20‰盐度条件下获得最大生物量177.78 mg/L;在30‰盐度条件下获得最大脂肪酸含量123.99 mg/g;p H值8.0条件下,三角褐指藻生物量浓度及脂肪酸含量均达到最大值(166.39 mg/L和145.92 mg/g),而在p H值7.5条件下,三角褐指藻的生长受到抑制。尿素作为氮源较碳酸氢铵更有利于三角褐指藻的生长,最终生物量为150.83 mg/L,但以碳酸氢铵为氮源条件下,更利于脂肪酸的积累,脂肪酸含量达到169.72 mg/g。因此,户外跑道池中的最适培养条件为盐度20‰、p H值8.0、尿素为氮源。     

氮源对等鞭金藻生长和脂肪酸组成的影响

研究了在培养基中添加不同浓度的NaNO3、NH4 Cl、NH2 CONH2 对等鞭金藻生长和脂肪酸组成的影响。结果表明 ,当不在培养基中添加氮源时 ,等鞭金藻生长缓慢。但C16∶0 ,C18∶0 和多不饱和脂肪酸 (PUFAs)占总脂肪酸的比例最高。氮浓度在 0 9～ 7 0mmol/L之间 ,等鞭金藻的生长随着NH4 Cl浓度的增加而下降 ,随着NH2 CONH2 浓度的增加而升高 ,而受NaNO3浓度变化的影响不显著。以NaNO3或NH2 CONH2 为氮源 ,DHA占总脂肪酸的比例随着其浓度的增加先上升后下降 ,最适浓度为 3 5mmol/L。以NH4 Cl或NH2 CONH2 为氮源 ,PUFAs占总脂肪酸的比例随着氮浓度的增加而下降 ,且等鞭金藻DHA占干重的比例在 1 8mmol/L的浓度时达到最高 ,分别为1 8%和 1 6% ;以NO- 3为氮源 ,在浓度为 3 5mmol/L时DHA含量最高 ,为 2 2 %。在相同氮浓度下 ,DHA占干重的比例以NaNO3为氮源最高 ,以NH2 CONH2 为氮源时最低。     

光照对眼点拟微绿球藻和三角褐指藻生长及总脂的影响

研究了不同光照强度及单、双侧光照对眼点拟微绿球藻(Nannochloropsis oculata)和三角褐指藻(Phaeodactylum tricornutum)的生长、总脂及叶绿素a的影响.结果表明:眼点拟微绿球藻的生物量随光照强度的增加而升高,相同光照强度下单侧光照优于双侧;三角褐指藻的生物量受光照强度及单、双侧光照的影响不明显.眼点拟微绿球藻的总脂含量随光照强度的升高先增加后减少;三角褐指藻的总脂含量随光照的增强呈上升趋势.两种藻的叶绿素a含量随藻体总脂含量的升高而降低.综合考虑,眼点拟微绿球藻较三角褐指藻进行油脂生产更有优势.     

三角褐指藻跑道池规模化培养及岩藻黄素积累条件的优化

岩藻黄素是一种广泛存在于海洋藻类的类胡萝卜素,具有清除自由基、抗癌和抗肥胖等生理活性,尤其在抗肿瘤和减肥方面功效突出。三角褐指藻中的岩藻黄素含量丰富,而环境因子及营养因素对微藻生长及岩藻黄素含量有着显著影响。本文以OD值、细胞密度、干重和岩藻黄素含量等为评价指标,研究了不同盐度(20、25、30)、pH值(7.5、8.0、8.5)、氮源种类(尿素、碳酸氢铵)等因素对三角褐指藻户外生长、岩藻黄素积累的影响。研究表明:盐度为20条件下,三角褐指藻获得最大细胞密度6.01×10~6/m L,不同盐度对岩藻黄素含量的增长无明显效果;pH值8.0条件下,三角褐指藻细胞密度及岩藻黄素含量均达到最大值(5.8×10~6/m L和17.79 mg/g);与碳铵相比尿素作为氮源更有利于三角褐指藻的生长,最终细胞密度为4.1×10~6/m L,但以碳铵为氮源条件下,更利于岩藻黄素的积累,岩藻黄素含量达到9.96 mg/g。因此,户外跑道池中的最适培养条件为盐度20、pH值8.0、碳铵为氮源。     

氮源对小球藻光合作用和色素积累的影响

本文研究了自养培养条件下尿素、NH4NO3、(NH4)2SO4和NaNO3四种氮源对小球藻(Chlorella sp.TCCC45058)生长、光合作用以及叶绿素a产率的影响。实验结果显示,NaNO3是Chlorella sp.TCCC45058生长的最佳氮源,以NaNO3为氮源时得到最高细胞密度4.1×107个/mL;而尿素对藻细胞色素积累最有利,最高叶绿素a产率达到21 mg/g。培养过程中,不同氮源会对培养液pH造成不同影响,以NaNO3为氮源时,随着NO3-的消耗培养液pH会出现显著的上升;以(NH4)2SO4为氮源时pH呈下降趋势;而尿素和NH4NO3则不会对其产生明显影响。将pH维持在中性不会对各组氮源培养效果产生显著影响,因此实际生产中无需对培养基pH做全程控制。     

三角褐指藻跑道池规模化培养及岩藻黄素积累条件优化

岩藻黄素是一种广泛存在于海洋藻类的类胡萝卜素,具有清除自由基、抗癌和抗肥胖等生理活性,尤其在抗肿瘤和减肥方面功效突出。三角褐指藻中的岩藻黄素含量丰富,而环境因子及营养因素对微藻生长及岩藻黄素含量有着显著影响。本文以 OD 值、细胞密度、干重和岩藻黄素含量等为评价指标,研究了不同盐度（20、25、30）、p H 值（7.5、8.0、8.5）、氮源种类（尿素、碳酸氢铵）等因素对三角褐指藻户外生长、岩藻黄素积累的影响。研究表明：盐度为 20 条件下,三角褐指藻获得最大细胞密度 6.01×106/m L,不同盐度对岩藻黄素含量的增长无明显效果;p H 值 8.0 条件下,三角褐指藻细胞密度及岩藻黄素含量均达到最大值（5.8×106/m L 和17.79 mg/g）;与碳铵相比尿素作为氮源更有利于三角褐指藻的生长,最终细胞密度为 4.1×106/m L,但以碳铵为氮源条件下,更利于岩藻黄素的积累,岩藻黄素含量达到 9.96 mg/g。因此,户外跑道池中的最适培养条件为盐度 20、p H 值 8.0、碳铵为氮源。     

不同氮浓度对紫球藻生长及藻胆蛋白和叶绿素a含量变化的影响

通过研究不同NaNO3浓度下紫球藻细胞密度、生长速率及生长末期细胞内藻胆蛋白和叶绿素a含量的变化,系统探讨不同NaNO3浓度下对紫球藻生长代谢的影响.实验表明,NaNO3添加量为0、0.1g/L时,紫球藻生长稳定期缩短,NaNO3添加量为0.4g/L～1.2g/L时,紫球藻生长速率差别很小且稳定期延长;紫球藻在不同浓度下生长稳定期含叶绿素a、藻胆蛋白的含量与藻体生长状况呈明显的正相关规律,即藻体稳细胞密度越大,累积产物总含量越高.     

磷限制对三角褐指藻脂质含量及相关基因表达的影响

为了提高微藻生产油脂能力,本论文研究了不同浓度磷限制（0、16、32、48、64 μmol/L）对三角褐指藻细胞生长、总脂含量、叶绿素a含量和脂质合成相关基因表达量的影响,为三角褐指藻油脂的规模化生产和分子机理研究提供了理论基础。结果表明,磷限制虽然极显著地抑制了三角褐指藻细胞生长和叶绿素a含量,但却极显著地促进了脂质的积累。当磷浓度为0 μmol/L时,三角褐指藻细胞密度与对照组（64 μmol/L）相比极显著下降,下降了21.6%,但其脂质含量与对照组相比极显著上升,上升了61.64%。RT-QPCR分析结果表明：磷浓度为0 μmol/L时,FABD、DLD、FAD2、FABI、PTD12和ACC1等6个基因的表达量均极显著上调,这和磷浓度为0 μmol/L时的总脂含量变化一致,说明磷限制是通过促进脂质合成相关基因的表达来促进三角褐指藻脂质的积累的。主成分分析表明,DLD、FAD2和ACC1 3个基因是对脂质合成的主要贡献因子,累计贡献率达89.916%。     

温度对海洋微藻生长及脂肪酸组成的影响

研究了不同温度下,三角褐指藻和等鞭金藻生长及脂肪酸组成.结果表明,三角褐指藻的最适生长温度为20℃,而等鞭金藻的最适生长温度为25℃.无论是三角褐指藻的EPA还是等鞭金藻的DHA,均随着培养温度的升高而下降.低温有利于三角褐指藻积累EPA和PUFAs,但PUFAs含量（W/W）在10-20℃之间差异不显著（P＞0.05）.虽然等鞭金藻DHA含量随着温度的上升而下降,但PUFAs在20℃时含量（W/W）最高,为10.5%.不同海洋微藻不仅具有不同的生长温度,且最适PUFAs合成的温度也不同.     

Influence of nitrogen source on the synthesis of fat from sucrose by Aspergillus terreus, Aspergillus ochraceus, Cladosporium fulvum, Cladosporium herbarum and penicillium gladioli

The influence of ammonium nitrate, ammonium sulphate, ammonium chloride, sodium nitrate, potassium nitrate and urea as nitrogen sources on the synthesis of fat by Aspergillus terreus, Aspergillus ochraceus, Cladosporium fulvum, Cladosporium herbarum and Penicillium gladioli has been studied. Sodium nitrate has proved to be the best source of nitrogen for production of fat by A. terreus, C. herbarum and C. fulvum where the highest yields obtained were of fat contents in the felt of 51.0, 29.2 and 23.5 %, respectively. In the case of A. ochraceus the highest yield of fat was obtained with urea as nitrogen source giving a fat content in the mycelium of 47.5%. The highest yield of fat by P. gladioli was obtained using ammonium nitrate, giving a fat content of 31.0%.     

不同碳氮组合对三角褐指藻兼养生长及脂质积累的影响

为了探讨兼养培养中不同碳氮组合对三角褐指藻(P.tricornutum)生长及脂质积累的影响,以葡萄糖为碳源,氯化铵为氮源,以不同的碳氮组合兼养培养P.tricornutum,用干重法测定P.tricornutum的生物量,三氯甲烷-甲醇法提取脂质,并采用GC分析脂肪酸组成。结果表明,兼养生长中P.tricornutum基于氯化铵消耗的细胞得率系数随着葡萄糖质量浓度的增加而降低,降低了对氮源的需求;在碳氮组合为葡萄糖质量浓度0.5 g/L,氯化铵浓度1.0 mmol/L的条件下,P.tricornutum生物量达最高,为1.25 g/L,脂质含量可达44.6%,不同碳氮组合对P.tricornutum脂质多不饱和脂肪酸(PUFA)和二十碳五烯酸(EPA)含量的影响不显著。     

硝态铵态氮比例对不同氮效率烟草苗期氮素吸收及利用的影响

【目的】为明确最有利于烤烟和白肋烟氮素利用的氮素形态配比。【方法】采用盆栽的方法,以烤烟品种中烟100和白肋烟品种TN90为材料,设置5个硝态铵态氮比例(T1:NO₃^-:NH₄⁺=100:0;T2:NO₃^-:NH₄⁺=75:25;T3:NO₃^-:NH₄⁺=50:50;T4:NO₃^-:NH₄⁺=25:75;T5:NO₃^-:NH₄⁺=0:100),测定各处理的生物量、色素含量、硝酸还原酶(nitrate reductase,NR)和谷氨酰胺合成酶(glutamine synthetase,GS)活性、NH₄⁺-N含...     

Effect of Culture Variables on Mycelial Arachidonic acid Production by Mortierella alpina

Effect of culture conditions on biomass, lipid, and arachidonic acid production was investigated in the oleaginous fungus Mortierella alpina CBS 528.72 under shake flask conditions. Several factors have been found to affect the biomass buildup and lipogenesis in this fungus, complicated by the fact that different strains demonstrate varying optimization conditions. Growth, lipid accumulation, and arachidonic acid production in the strain investigated were influenced by media, pH, temperature, carbon source, nitrogen source, etc. The results indicated that the most effective medium for growth and arachidonic acid production was glucose yeast extract medium. The optimum pH and temperature were found to be 6.5 and 28°C, respectively. On the same weight basis, glucose was the most efficient carbon source for biomass and lipid production in this fungal strain which yielded 6.8 g/L dry biomass and 40.2% (w/w) total lipid after 7 days of cultivation. Maximum arachidonic acid (ARA) production of 40.41% achieved in rhamnose-containing media was not concomitant with higher biomass and lipid yields. Efficacy of organic carbon sources, viz, yeast extract and peptone over inorganic sources like sodium nitrate, ammonium sulfate, ammonium chloride, etc, was established in the present study. M. alpina CBS 528.72 grown in peptone acquired the highest lipid content (42.0% (w/w)). However, the ARA content (28.74%) proved to be significantly less than that grown in yeast extract (35.28%). Furthermore, it was found that the biomass and ARA production declined drastically in a medium with vegetable oils as the sole carbon source but triggered the lipogenic pathway leading to higher accumulation of total lipids. Under the ideal conditions mentioned above, the maximum biomass, total lipid, and arachidonic acid production were 6.8 g/L, 41.6%, and 35.28% total fatty acid, respectively, in shake flask system.     

Effect of nitrogen source on oxalate accumulation in Setaria sphacelata (cv. Kazungula)

Setaria sphacelata (cv. Kazungula) was grown under controlled environment conditions on sand provided with mineral nutrient solutions containing nitrate, ammonium, urea, or nitrate plus ammonium as sole nitrogen sources. Growth in urea or ammonium resulted in small but significant decreases in oxalate concentrations of foliage compared with growth in nitrate, but nitrogen source had little effect on plant growth rates. Similar levels of potassium and total nitrogen were found in foliage from all treatments. Nitrate concentration was highest in leaves of plants supplied nitrate plus ammonium and lowest in leaves of plants supplied only ammonium as the nitrogen source. Nitrate reductase activity was virtually absent from new fully expanded leaves from all treatments, but readily detectable in young regrowth when highest activities were associated with the nitrate plus ammonium treatment and lowest with ammonium alone. Leaves continued to accumulate oxalate after reaching maturity and it is considered that anions other than nitrate must be responsible for the cation excess which prompts the synthesis of this oxalate. No diurnal variation in oxalate content of controlled environment or field grown Setaria sphacelata was observed.     

不同氮源海藻肥对无土栽培生菜生长及品质的影响

本研究用海带浸泡液复配酰胺态氮、植物氨基酸粉、鱼蛋白三种氮源制成肥料,分别探讨了不同稀释度对生菜生长及品质的影响。结果表明:与改良霍格兰配方对比,氨基酸粉海藻肥稀释倍数为3000 倍时,生菜鲜重、叶绿素、还原糖、蛋白含量分别增加23.21%、4.21%、35.48%、35.71%,硝酸盐含量降低了60.31%;鱼蛋白海藻肥稀释倍数为2000 倍时,生菜鲜重、叶绿素、还原糖、蛋白含量分别增加21.94%、14.81%、15.21%、24.85%,硝酸盐含量降低了57.96%;酰胺态氮(尿素)海藻肥稀释倍数为1800 倍时,生菜鲜重、还原糖、蛋白含量分别增加15.25%、16.31%、8.33%,硝酸盐和叶绿素含量分别降低了2.10%、15.09%。研究结果表明氨基酸粉海藻肥最适宜作为生菜无土栽培的有机肥。     

Nitrogen fertiliser source effects on the growth and mineral nutrition of pepper (Capsicum annuum L.) and wheat (Triticum aestivum L.)

BACKGROUND: The presence of stable mixed nitrogen forms (such as nitrate/ammonium/urea or nitrate/urea) in the soil solution is due to the use of nitrification and/or urease inhibitors in urea‐based fertilisers. However, there is no specific information in the literature comparing the efficiency of these urea mixed nitrogen forms as a nitrogen source for plants with that of nitrate and ammonium/nitrate. The aim of this study was to compare the effects on plant growth and mineral nutrition of different nitrogen forms, including mixed nitrogen forms containing urea. RESULTS: The results indicated that for both wheat (Triticum aestivum L.) and pepper (Capsicum annuum L.) the growth of plants fed mixed nitrogen forms containing urea was generally similar to that of plants receiving nitrate and nitrate/ammonium. Only in the case of pepper did ammonium/urea nutrition cause a significant decrease in plant growth. The presence of nitrate corrected the negative effects of mixed nitrogen forms containing ammonium and/or urea on the growth of pepper plants. CONCLUSION: Mixed nitrogen forms containing urea did not cause any negative effect on plant growth or mineral nutrition. In fact, plants fed mixed nitrogen forms containing urea had higher shoot concentrations of potassium, phosphorus, iron and boron than plants receiving nitrate. Copyright © 2007 Society of Chemical Industry     

无机氮源对红曲霉调控初探

采用以硫酸铵、硝酸铵、硝酸钾、亚硝酸钠4种不同的无机盐作为氮源,探讨其对红曲霉（Monascus）菌株GZUM-25菌落形态、菌丝形态以及色素种类和产量的影响。结果表明,在以硫酸铵为氮源的培养基上,红曲霉菌落的基质菌丝和气生菌丝生长紧密,且气生菌丝在边缘呈放射状,菌丝粗壮、分支多,色素种类多且色价最高为13.5 U/mL;在以硝酸钾为氮源的培养基上,菌落基质菌丝较为疏松,气生菌丝呈毛绒状,菌丝较为粗壮但不具有分支,色素种类单一,色价较高为1.91 U/mL;在以亚硝酸钠为氮源的培养基上,菌落基质菌丝细长且不具有分支,色价最低0.08 U/mL。由此可知,铵盐可以促进红曲霉菌丝的生长发育和次级代谢产物的生成,而亚硝酸盐则有抑制作用。