优化灵芝真菌发酵条件的研究

通过摇瓶试验研究确定转速、接种量、通气量为影响灵芝真菌罐上发酵培养的影响因素,以菌体量、胞外多糖产量为目的产物,利用L9（34）正交试验进行7L发酵罐发酵条件优化,分析得出灵芝真菌培养的最佳工艺条件为：转速200r／min、接种量15％、通气量200L／h;菌丝体最大产量为7．35g／L,胞外多糖干重最高产量为0．92g／L。菌体量与胞体多糖产量存在线性关系,得到回归方程为y=0．0275x＋0．5968。     

溶氧控制条件对双孢菇发酵产胞外多糖的影响

以双孢蘑菇(Agaricus bisporus MJ-0811)为实验菌种,采用5L自控式发酵罐培养研究溶氧控制条件(搅拌转速和通气量)对双孢菇发酵过程的影响,考察发酵过程中菌体生物量、胞外多糖产量、相对溶氧、葡萄糖含量的变化。结果表明:搅拌转速和通气量对双孢菇的菌体生长和胞外多糖分泌具有显著的影响,并得出较佳的培养条件为:温度25℃、搅拌转速160r/min、通气量0.9vvm,此条件下,培养5d,菌体生物量最高达20.81g/L,胞外多糖产量最高达3.75g/L。     

裂褶菌放大培养条件的研究

以裂褶菌菌丝体和胞外多糖为目标产物,研究了裂褶菌从摇瓶、5L发酵罐至50L发酵罐的放大培养条件.根据单位体积发酵液所消耗的通气功率相等和单位体积发酵液通风量相等的准则,进行了主要控制参数-搅拌转速的理论放大计算,确定了裂褶菌50L发酵罐放大培养的理论搅拌转速为150r/min,通风量为30L/min;通过搅拌转速对菌体和胞外多糖产量影响的研究,确定了在发酵中后期采用阶梯式调整搅拌转速的发酵工艺,成功实现了由摇瓶至50L发酵罐的裂褶菌放大培养,裂褶菌菌丝体和胞外多糖的产量分别由原来的13.25g/L和3.14g/L提高至放大后的17.09g/L和7.74g/L.     

桑黄菌液体发酵工艺条件的研究

为能够提高桑黄液体菌丝体粗多糖产量,通过单因素试验,以菌丝生物量及菌丝多糖产量为指标,考察了接种龄、发酵液初始pH、装液量、接种量以及摇床转速等因素对其的影响,采用正交试验确定较佳发酵条件。结果表明:当装液量130mL/500mL,pH5.5,摇床转速180r/min时,菌丝生物量达18.2g/L,桑黄胞外粗多糖产量达6.02g/L。     

香菇多糖提取工艺的研究

本文对香菇液体深层发酵液中香菇胞内、胞外多糖的提取工艺进行了研究。结果发现，在4℃以下，发酵液pH7．0时，采用乙醇分步沉淀法从香菇发酵液中提取胞外多糖可使粗多糖得率从一次性沉淀的3．0g／L提高到3．8g／L。利用响应面分析(RSA)结果得到胞内多糖的提取工艺参数为：92．5℃，3h，湿苗体：水为1：2．5。在此条件下，采用机械法处理香菇苗丝体，多糖得率从未处理时的6g／kg干菌体提高到12．62g／kg干菌体。     

灰树花液态深层发酵条件研究

以菌丝体生物量和多糖含量为评价指标,通过单因素试验研究了灰树花的液态深层发酵条件,并考察不同发酵罐类型对灰 树花生长的影响,在此基础上利用50 L发酵罐进行了扩大培养。 结果表明,利用7 L搅拌式发酵罐,灰树花的最优液体深层发酵条件为培 养温度23 ℃,搅拌速度120 r/min,通气量3 L/min。 在此优化条件下,菌丝体生物量和发酵液中多糖含量分别为11.659 g/L和3.658 g/L, 且高于气升式发酵罐。 在50 L搅拌式发酵罐中成功实现了扩大培养,其菌丝体生物量和多糖含量分别为13.238 g/L和3.178 g/L。     

裂褶菌菌丝体与胞外多糖发酵条件研究

在7 L发酵罐上进行了裂褶菌发酵生产菌丝体和胞外多糖的研究,采用L_9(3~4)正交试验对发酵条件进行了优化。在7 L发酵罐上裂褶菌的适宜培养条件为:搅拌转速200 r/min、接种量10%(V/V)、通气量200 L/ h,在此条件下发酵120 h,获得的菌丝体和胞外多糖产量最高,分别为16.23 g/L和1.68 g/L。相关性分析表明,裂褶菌菌丝体产量与胞外多糖产量之间存在线性关系。     

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。     

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。     

不同搅拌速度对松口蘑菌丝体发酵的影响

在摇瓶发酵条件优化的基础上,研究了松口蘑在25L搅拌式发酵罐上的分批放大实验,探讨了不同搅拌转速对菌丝生物量、生产强度、pH、溶氧及对菌丝形态的影响,在发酵温度25℃,通风量0.8vvm,罐压0.5kg/cm2的条件下,最佳搅拌转速为100r/min。发酵培养8d后,发酵液由浑浊变为澄清,上清液亮黄色,菌丝形态呈均匀颗粒状,菌丝生物量增加趋于平缓,最高可达11.5g/L。     

稀土元素镨、钕、铒对红菇多糖深层发酵的影响

研究了稀土元素镨、钕、铒对红菇深层发酵中红菇菌丝生物量、胞外多糖(EPS)、胞内多糖(IPS)、总多糖(TPS)、最终pH和多糖产率的影响。研究结果显示:稀土元素显著影响着菌丝生物量、EPS、IPS、TPS、最终pH和多糖产率;其影响水平受限于稀土元素的种类和稀土元素含量,适当剂量的稀土元素镨、钕具有促进红菇菌丝体生长作用和代谢产物的积累,而过高浓度的稀土元素则会造成对细胞生长和多糖产物抑制作用。在添加适宜的剂量稀土元素镨时能够获得较高的生物量、胞外多糖产量、胞内多糖产量、总多糖和胞外多糖产率,其分别达到24.63±0.62g/L、1.730±0.065g/L、79.03±0.00mg/g、3.511±0.028g/L、7.60%±0.15%。     

灵芝菌体液态深层发酵条件的优化

研究摇瓶灵芝菌体液态深层发酵温度和初始pH 值,在此基础上进行5L 发酵罐批次培养,研究发酵过程pH 值控制、溶氧控制对灵芝菌体生长和灵芝胞外多糖的影响。结果表明：发酵温度30℃,初始pH 值为6.0;过程pH 值控制策略：菌体生长前期(0～40h)控制pH 值为5.5,40～48h 控制pH 5.0,48h 后至发酵结束控制pH4.5;溶氧控制策略为：搅拌转速160r/min,通风量0.75vvm。优化后的验证实验结果：灵芝菌体生物量最高达到19.7g/L,胞外多糖最高达到3.23g/L,较优化前灵芝菌体生物量12.8g/L 和灵芝胞外多糖2.39g/L 分别提高了53.9% 和35.1%。     

磁场处理对螺旋藻生长及胞外多糖的影响

系统研究外加磁场作用对螺旋藻生长及其胞外多糖分泌的影响。研究发现,在40kA/m以下范围内,磁处理有利于螺旋藻细胞生长及生物量的积累,并当磁场强度为24kA/m时比生长速率最高。磁场强度高于40kA/m后螺旋藻的生长受到一定抑制,达到80kA/m以上时生长受到明显抑制,400kA/m以上则基本停止生长。在较高的磁场强度下螺旋藻生长缓慢但却有利于螺旋藻胞外多糖的分泌。螺旋藻对数生长期进行磁处理效果最好。     

天麻中香草醇对灰树花菌丝体生物量和胞外多糖合成的影响

目的 探讨高血压亚急症患者循环内皮祖细胞(EPC)功能的改变以及一氧化氮(NO)、肱动脉血流介导的内皮依赖性舒张功能(FMD)与EPC功能的关系。方法 招募高血压亚急症患者13例,血压正常者20例(对照组),取外周血提取原代EPC培养后以Transwell小室和CCK-8法评估EPC的迁移、黏附和增殖能力,通过检测FMD、血浆和EPC分泌的NO、粒-巨噬细胞集落刺激因子(GM-CSF)、血管内皮生长因子(VEGF)、白细胞介素6(IL-6)水平评估血管内皮功能。结果 高血压亚急症组与对照组相比,EPC细胞功能(包括迁移、增殖和黏附能力)明显下降(P＜0.05)；血浆及EPC分泌的NO水平有明显差异(P＜0.05)；血浆及EPC分泌NO水平均与EPC迁移、黏附和增殖能力呈明显的线性关系(P＜0.05)；FMD与EPC迁移、黏附和增殖能力具有明显相关性(P＜0.05)。两组血浆和EPC分泌的GM-CSF、VEGF、IL-6水平均无明显差异(P＞0.05)。结论 相对血压正常者,高血压亚急症人群的EPC功能(迁移、黏附和增殖)明显下降,且NO水平和FMD均与EPC功能正相关。     

Growth and exopolysaccharide yield of Lactobacillus delbrueckii ssp. bulgaricus DSM 20081 in batch and continuous bioreactor experiments at constant pH

Some Lactobacillus delbrueckii ssp. bulgaricus strains are able to synthesize exopolysaccharides (EPS) and are therefore highly important for the dairy industry as starter cultures. The aim of this study was to investigate the nutritional requirements for growth and EPS production of Lactobacillus delbrueckii ssp. bulgaricus DSM 20081. A medium was developed from a semi-defined medium (SDM) in which glucose was replaced by lactose and different combinations of supplements (nucleobases, vitamins, salts, sodium formate and orotic acid) were added. Constant pH batch fermentation with the modified medium resulted in an EPS yield of approximately 210 mg glucose equivalents per liter medium. This was a 10-fold increase over flask cultivation of this strain in SDM. Although not affecting cell growth, the mixture of salts enhanced the EPS synthesis. Whereas EPS production was approximately 12 mg/g dry biomass without salt supplementation, a significantly higher yield (approximately 20 mg/g dry biomass) was observed after adding the salt mixture. In continuous fermentation, a maximal EPS concentration was obtained at a dilution rate of 0.31/h (80 mg EPS/L), which corresponded to a specific EPS production of 49 mg/g dry biomass.     

Bistage control of pH for improving exopolysaccharide production from mycelia of Ganoderma lucidum in an air-lift fermentor

It was found that pH control definitely affects mycelial cell growth and exopolysaccharide (EPS) production of the mycelial cultivation of Ganoderma lucidum. Compared to the case of uncontrolled pH cultivation, a culture system whose pH was kept constant at 3 and 6 exhibited improved mycelial cell growth and EPS production, respectively. The bistage pH control technique, that is, shifting the pH from 3 to 6 at the initial phase of the exponential growth, is introduced to improve cell growth and EPS production. This technique can greatly increase EPS production to 20.1 g/l from 4.1 g/l in the case of uncontrolled pH cultivation, without adverse effects on cell growth as in the case of constant maintenance of a high pH. It was also proved that bistage pH control retained the desirable morphologies of the mycelia during cultivation and resulted in low viscosity and yield stress of the culture broth. It will be useful for the application of the culture process to mycelial growth in a large-scale fermentor.     

Bistage control of pH for improving exopolysaccharide production from mycelia of Ganoderma lucidum in an air-lift fermentor

It was found that pH control definitely affects mycelial cell growth and exopolysaccharide (EPS) production of the mycelial cultivation of Ganoderma lucidum. Compared to the case of uncontrolled pH cultivation, a culture system whose pH was kept constant at 3 and 6 exhibited improved mycelial cell growth and EPS production, respectively. The bistage pH control technique, that is, shifting the pH from 3 to 6 at the initial phase of the exponential growth, is introduced to improve cell growth and EPS production. This technique can greatly increase EPS production to 20.1 g/l from 4.1 g/l in the case of uncontrolled pH cultivation, without adverse effects on cell growth as in the case of constant maintenance of a high pH. It was also proved that bistage pH control retained the desirable morphologies of the mycelia during cultivation and resulted in low viscosity and yield stress of the culture broth. It will be useful for the application of the culture process to mycelial growth in a large-scale fermentor.     

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.     

运用多元数学模型优化灰树花发酵培养基组成的研究

利用BoxBehnken3×3设计优化了影响灰树花深层发酵菌丝体和胞外多糖生产的主要培养基组成,碳源(葡萄糖)、氮源(蛋白胨)和无机盐(KH2PO4),响应面分析结果表明,各因素及其交互作用对响应值灰树花菌丝体和胞外多糖产量均存在显著的相关性。通过典型性分析,获得最大菌丝体量(17.61g/L)时,培养基组成为:葡萄糖45.2g/L,KH2PO42.97g/L,蛋白胨6.58g/L,MgSO4·7H2O1g/L和玉米浆15g/L;而获得最佳胞外多糖量(1.326g/L)时的培养基组成为:葡萄糖58.6g/L,KH2PO44.06g/L,蛋白胨3.79g/L,MgSO4·7H2O1g/L和玉米浆15g/L。与其他实验组的结果相比,优化后的灰树花菌丝体与胞外多糖的量都有较大的增加。15L发酵罐扩大培养的结果表明,在优化培养基组成的条件下,扩大培养后的菌丝体产量最大值达22.50g/L。     

发酵法生产桑黄胞外多糖条件的研究

以单因子摇瓶实验和响应面分析对药用真菌桑黄培养基进行了优化,确定了优化培养基(g/L):蔗糖50、玉米浆3.0、KH2PO410.0、MgSO41.0、CaCl23.0、VB1200μg/L。在优化条件下,研究了0~168h,桑黄发酵pH、总糖、还原糖、胞外多糖、生物量的变化情况。摇瓶发酵结果表明,整个过程中pH变化不明显,总糖含量先降后升,生物量先增后趋于稳定,于120h达最大值11.012 g/L,胞外多糖在144h达最大2.594 g/L,生产强度为0.018 g/(L.h)。经7 L发酵罐放大实验表明,桑黄代谢与摇瓶存在一定差异,胞外多糖的合成速度更快,于120 h达最大值3.283 g/L,生产强度为0.027 g/(L.h),与摇瓶相比分别提高了26.5%和50%。