醋酸盐对螺旋藻生长和多糖及光合色素含量的影响

研究表明,醋酸钠作为有机碳源能显著提高螺旋藻的生长速率和细胞产率,同时还可促进螺旋藻多糖和光合色素的生成。本试验得出醋酸钠浓度为3.0g/L时,螺旋藻获得1.51g/L的最大细胞产率,与对照相比,细胞产率提高了近40%。添加醋酸钠后多糖含量最高可增加1.2倍左右,光合色素含量几乎增加一倍。     

pH值对钝顶螺旋藻生长的影响

pH值不但影响培养液中营养基质的离解程度，而且对螺旋藻的生长、代谢乃至细胞形态都造成显著的影响。本文得出：钝顶螺旋藻生长的pH范围为8.5～10．0，最适生长pH为9．0～9．6，pH值超过10．5时，对螺旋藻的生长产生抑制作用。混合营养培养时，通过对螺旋藻生长过程中pH值变化的研究，得出：与无机碳源相比，有机碳源作为营养源更易被螺旋藻利用并合成细胞物质。     

山药、苦荞对灰树花深层发酵产胞外多糖的影响

灰树花是一种药食两用真菌,可用液体深层发酵大规模生产灰树花胞外多糖。试验采用现代化的液体深层发酵技术,添加山药和苦荞,可分别使灰树花胞外多糖产量较传统液体深层发酵技术提高1．2g／L和0．5g／L左右。同时,对碳源、氮源作了进一步优化,为今后深入研究如何提高灰树花胞外多糖产量奠定了基础。     

螺旋藻混合营养培养中碳源分析

对螺旋藻混合营养培养过程中无机碳HCO3-和有机碳源葡萄糖进行详细的检测及分析,结果表明:在培养3d时各组所添加的葡萄糖基本用完,培养9d时,葡萄糖浓度为3.0g/L组培养液HCO3-含量最低.同时优选了螺旋藻混合营养培养的NaHCO3添加量,研究发现NaHCO3含量对螺旋藻混合营养细胞积累有很大的影响,NaHCO3的浓度在8.4g/L～16.8g/L时基本对螺旋藻生物量的积累没有太大的影响.     

悬浮培养霍山石斛原球茎合成活性多糖的研究

本文考察了基本培养基、碳源、氮源以及有机添加物对霍山石斛原球茎液体培养合成活性多糖的影响。在MS、B5、N6、SH及各自1／2基本培养基中，以1／2MS和N6最适多糖合成，继代培养30d，总多糖产率分别达到479．47mg／L和417．05mg／L。使用单一碳源时，葡萄糖对多糖的积累优于蔗糖和果糖，在30g／L时，总多糖产率达到1034．96mg／L。在一定浓度范围内，氮源种类对多糖的合成影响不太明显，但氮源浓度是主要冈素，以10mmol／L最佳。另外，100g／L的马铃薯提取液与100g／L的香蕉提取液均有利于多糖的合成。     

干酪乳杆菌LC2W合成胞外多糖培养基成分的优化

研究了不同培养基对干酪乳杆菌LC2W胞外多糖产量的影响，并研究了以脱脂乳为基础培养基，添加不同碳源、氮源和其他盐类对LC2W胞外多糖产量的影响。结果表明，不同培养基对LC2W胞外多糖产量影响较大，其中PTYG和脱脂乳培养基胞外多糖产量较高；以脱脂乳培养基为基础培养基，添加质量分数1．0％大豆蛋白胨、1．5％葡萄糖、0．1％的K2HPO4可以提高胞外多糖产量28.75％。     

羊肚菌液体深层发酵条件

以羊肚菌为材料，研究了发酵过程中碳源、氮源、无机盐、培养条件对菌丝体生物量、胞外多糖的影响，以及发酵过程中菌丝体生物量、胞外多糖、总糖及还原糖质量浓度、培养基PH值的动态变化，并在此基础上确定了羊肚菌液体深层发酵的最佳条件。结果表明：羊肚菌液体深层发酵的最优培养基配比为：玉米粉4．0g／dL、葡萄糖1．0g／dL、黄豆粉2．0g／dL、酵母粉0．3g／dL、KH2PO4 0．2g／dL、MgSO4 0．1g／dL、CaSO4 0．1g／dL；最优培养条件为：24℃，起始pH5．8，250mL的摇瓶装液量为100mL，接种量10mL，摇瓶转速140r／min，发酵时间为108h。     

关于蛹虫草菌多糖发酵及培养基的研究

研究了蛹虫草胞外多糖发酵过程，分析不同因素对胞外多糖得率的影响，获得了比较适宜的培养基组成和发酵条件。蛹虫草胞外多糖优化发酵培养基组成为：蔗糖12％，玉米浆2％，酵母膏2％，硝酸钾0．45％；发酵培养条件为：pH值6．5，温度20℃。此条件下蛹虫草胞外多糖得率为1．188g／100mL，菌丝体干重为1．221g／100mL。     

深层发酵生产红菇菌丝体和多糖的培养基优化研究

研究了采用液体发酵法生产红菇菌丝体及红菇多糖的发酵培养基。研究了碳源、氮源和金属离子对红菇细胞生长及红菇多糖的影响。结果表明:葡萄糖作为最佳碳源有利于细胞生长和胞内外多糖等代谢产物的积累而获得高的多糖产率;酵母膏作为最适氮源能获得最高的菌丝生物量、胞外多糖产量和多糖产率,尽管此时胞内多糖处于一个稍低水平;金属离子也对细胞生长具有影响,在锌离子存在的情形下能够获得最佳的细胞生长及代谢产物累积效果。在最优化培养基的条件下,细胞干重、胞外多糖、胞内多糖、总多糖及多糖产率分别达到20.94g/L,1.54g/L,78.11mg/g,2.95g/L和8.13%。     

光照对螺旋藻形态及胞外多糖的影响和机理

系统研究了光照对螺旋藻生长、细胞形态、藻体颜色及胞外多糖积累的影响规律，结果表明，提高光照强度不仅有利于提高细胞生物量，同时能促进胞外多糖的分泌，也加速藻体的衰老。光照强度为20klx的生长速率和胞外多糖的分泌量分别是10klx的两倍和三倍。红光有利于螺旋藻的生长；绿光则能明显刺激螺旋藻胞外多糖的分泌。     

应用渗透膜高密度培养富硒螺旋藻

应用透析袋(OT法)组装光生物反应器,与鼓泡式生物反应器(AB法)和摇瓶(SB法)进行对比实验,探讨利用渗透膜建立高密度培养富硒螺旋藻(Se-SP)方法的可行性。称质量法监测并推算藻细胞生长率和最大生物量,荧光光度法测定Se-SP及其培养液中硒含量和形态变化,分光光度法检测Se-SP中总蛋白(TP)、藻蓝蛋白(PC)、叶绿素a(Chla)、总胡萝卜素(Caro)、水溶性多糖(SPS)及巯基(-SH)含量等主要营养构成,培养液中无机碳(IC)和有机溶解碳(DOC)的含量采用自动分析仪测定。结果发现：OT法培养Se-SP的最大生物量可达9.6g/L,是AB和SB方法培养的3～5倍,其中有机硒转化率及TP、PC、Chla、SPS和-SH等主要营养成分的含量均有明显提高。相应地,培养基中 IC剩余减少, DOC无明显累积。结果提示,OT法可实现Se-SP高密度培养,并有望获得优质Se-SP产品,其优势体现在高细胞增殖速率、高有机硒转化率、高无机营养源消耗率和低有机碳的积累,便于培养液的再生利用,减少废液污染。     

碳酸氢铵为氮源对螺旋藻培养的影响

以碳酸氢铵作为氮源,研究在分批培养及流加培养条件下其对螺旋藻生长的影响。结果表明：当培养液中碳酸氢铵浓度小于5mmol/L时,螺旋藻生长正常;碳酸氢铵浓度超过5mmol/L时,螺旋藻生长受到抑制,解体死亡。采用生物量反馈补料的流加策略可以使培养液中螺旋藻生物量达到3.08g/L,产率达到0.26g/(L ·d),藻体中蛋白质及叶绿素含量分别达到65.06%和13.37mg/g,结果证实了碳酸氢铵为氮源高密度培养螺旋藻的可行性。     

营养强化混养条件下提高色绿藻生物量和虾青素产量

本研究在混养条件下,系统地比较了葡萄糖浓度、氮源种类以及不同碳氮比对色绿藻生物量和虾青素产率的作用规律。目的是在短时间内达到最高生物量同时获得较高含量的虾青素,为建立色绿藻高密度快速扩种和诱导积累虾青素应用技术提供科学依据。研究结果表明:在混养条件下,当葡萄糖浓度一定时,硝酸钠是细胞生长所需的最优氮源,6 d可达到最高生物量浓度9.23 g/L,平均比生长速率为0.24/d,虾青素产量为12.38 mg/L,虾青素占总类胡萝卜素的比例高达46.94%。至于不同碳氮比、葡萄糖浓度对色绿藻生物量和虾青素生产的影响,当葡萄糖浓度为30 g/L、C/N比为34为细胞生长的最优条件,生物量浓度最高为11.28 g/L,平均比生长速率高达0.32/d;虾青素含量显著优于其他组(p0.05),虾青素的产量为21.77 mg/L,虾青素占总类胡萝卜素的比例进一步提高到52.71%。本研究结果对于色绿藻高密度快速生长并积累大量虾青素的放大技术开发具有重要的指导意义。     

Submerged culture conditions for mycelial yield and polysaccharides production by Lyophyllum decastes

The effects of various carbon and nitrogen sources, their concentrations, initial pH and fermentation duration on the production of mycelia in terms of dry weight, exo-polysaccharide (EPS) and inner polysaccharide (IPS) by Lyophyllum decastes, a culinary-medicinal mushroom, were investigated in shake-flask cultures. Lactose, glucose and fructose were the top three best carbon sources for mycelial growth with corresponding yields of 6.73 g/l, 6.36 g/l and 6.10 g/l, respectively. Glucose was the best for production of EPS and IPS with 1.65 g/l and 317 mg/g dry mycelia, respectively. Maltose also performed well for EPS production. Yeast extract was the best nitrogen source for the production of mycelia (7.03 g/l) and IPS (325 mg/g dry mycelia), whereas EPS was improved further by increasing the yeast extract concentration (2.46 g/l at 2%). Similarly, initial pH 7 and 8 were best for polysaccharides production (EPS 1.73 g/l and IPS 320 mg/g) and mycelial growth (7.10 g/l), respectively. Maximum mycelial growth peaked at 15 days of cultivation whereas polysaccharides peaked at 10 days, and then tapered off. A concentration of glucose 3% and yeast extract 1% (mycelial yield and IPS) were found to be a suitable condition for submerged culture.     

Production of poly-beta-hydroxybutyric acid by microorganisms accumulated from river water using a two-stage perfusion culture system

The perfusion culture system using a shaken ceramic membrane flask (SCMF) was employed to accumulate microorganisms separated from river water and to produce poly-beta-hydroxybutyric acid (PHB). Using a two-step culture method with a single SCMF, river microorganisms were cultured by separately feeding four representative carbon sources, n-propanol, lactic acid, methanol, and formic acid. After 140 h culture, the cell concentration and PHB content respectively reached 43 g/l and 35% when a propanol medium was fed. Using a two-stage perfusion culture with twin SCMFs, the seed cell mass was increased in the first SCMF and then supplied to the second flask for PHB production. As a consequence, the cellular PHB content rose to 51% in the second SCMF, while the cell concentration gradually increased to 25 g/l after 175 h perfusion culture. These results demonstrated the utility of the two-stage perfusion culture system for developing a cheap means of producing PHB coincident with wastewater treatment.     

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。     

有机碳源对单针藻细胞生长、油脂积累和光合作用的影响

研究不同有机碳源对单针藻(Monoraphidium sp.)细胞生长,油脂积累和光合作用的影响,探讨其细胞生长和油脂积累的最佳碳源浓度。结果表明单针藻具有利用有机碳源进行混合营养生长的能力,葡萄糖、蔗糖对其细胞生长、总脂含量和光合放氧速率具有明显的促进作用,甘氨酸能够促进细胞生长,但总脂含量下降,乙酸钠则表现为抑制作用;在BG-11培养基中加入5g/L葡萄糖后,细胞生物量、总脂产量和光合放氧速率分别为7.8、3.2g/L和240.3μmolO2·(mg·chla)-1·h-1,是同等光合自养条件下的5.6、8.0和1.3倍;单针藻细胞生长、总脂积累的最佳葡萄糖添加浓度为10g/L。     

Sophorolipid production by Candida bombicola: medium composition and culture methods

Candida bombicola is able to produce sophorolipid molecules with surfactant properties when grown in a medium composed of two different carbon sources (usually sugar and oil) and a nitrogen source (frequently yeast extract). In this work, the composition of the medium and the culture method employed have been studied. The influences of glucose concentration, properties of oil and yeast extract concentration have been taken into account. Accordingly, a production medium composition is proposed (100 g/l glucose, 100 g/l sunflower oil and 1 g/l yeast extract). The most frequent culture methods reported in literature, i.e. batch, medium pulse mode and resting-cell methods, have been tested. The resting-cell method was found to produce the highest final concentration of sophorolipid, obtaining a good yield of carbon sources in a relatively short time. Under the best operational conditions and using the resting-cell method, 120 g/l sophorolipid was obtained in 8 d, with a carbon source yield of 0.60. Product distribution has also been investigated and the sophorolipid molecular structure of opened or cycled molecules has been determined under different operational conditions. Low yeast extract concentration and long fermentation time enhance the production of cycled structures by all the production methods studied.