红酵母发酵废糖蜜产类胡萝卜素的研究

对红酵母利用糖蜜发酵产类胡萝卜素进行了研究,结果表明:对糖蜜的预处理的最佳酸为硫酸;利用经过酸处理后的糖蜜发酵,菌株的生物量为30.75g/L,单细胞色素含量为104μg/g,色素产量为26mg/L;最佳发酵时间为168h。使用糖蜜代替葡萄糖做廉价碳源对红酵母进行发酵,确定添加量为170g/L,色素产量最大值为葡萄糖发酵的0.97倍,生物量为1.04倍。      

粘红酵母CA815固态发酵废弃烟梗产油脂的Plackett-Burman优化

目的资源化利用废弃烟梗(waste tobacco stem,WTS)并获取微生物油脂的廉价发酵基质。方法以一株粘红酵母(Rhodotorula glutinis)CA815为出发菌株,采用摇瓶方式固态发酵WTS,发酵后加入适量生理盐水并混合均匀,双层纱布过滤获得固态发酵的酵母生物量,采用酸热法提取酵母细胞油脂;采用Plackett-Burman(PB)实验设计法对影响微生物油脂产生的相关因素进行方差及贡献率分析。结果 PB试验结果统计学分析表明:在选择的11个相关因素中,酵母粉、蛋白胨和培养时间是影响酵母油脂产量的3个关键供试因素,粘红酵母CA815生物量最高值可达79.00 mg/g,油脂的最高产量可达4.633?g/g。结论粘红酵母CA815以WTS为主要基质,通过添加适量酵母粉和蛋白胨、优化培养时间,既可资源化利用WTS,又可通过固态发酵的方式获得微生物油脂。     

固定化酵母细胞转化肉桂酸生产L-苯丙氨酸

建立了一套较之传统方法更为准确的测定固定化细胞生产L-苯丙氨酸(L-phe)的新方法,采用高效液相色谱法(HPLC)测定反复冲洗凝胶所得冲洗液可以更准确地测定L-phe的生成,并采用新方法研究了固定化黏红酵母细胞的活力与稳定性。复合凝胶聚乙烯醇(PVA)+琼脂糖为最适载体,最佳质量浓度为PVA 120 g/L、琼脂糖10 g/L,反复冻融4次。此法得到的固定化细胞颗粒,机械强度良好,酶活保持时间长达200 h,L-苯丙氨酸产量高。通过流化床反应器测定其半衰期为100 h,200 h后总产量为44.58 mg/10 mL,固定化细胞无崩解现象。     

光镊拉曼光谱技术结合响应面法优化红酵母产类胡萝卜素的发酵条件

拉曼光谱具有快速、实时、无损分析的特点,在生物学领域应用广泛。作者利用光镊拉曼光谱技术(LTRS)测定红酵母细胞中类胡萝卜素。采用Plackett-Burman法对影响红酵母发酵的相关因素进行评价,发现葡萄糖、蛋白胨、pH和温度对类胡萝卜素的产量影响显著。利用BoxBehnken设计和响应面分析法对影响类胡萝卜素产量的关键因素进行优化,获得的最优发酵条件为:葡萄糖42.86 g/L,蛋白胨5 g/L,酵母提取物5 g/L,KH2PO41 g/L,MgSO4。7H2O 0.5 g/L,pH 7.0,温度28.3℃,优化后类胡萝卜素产量较优化前提高了45%。     

黏红酵母产油脂培养基的响应面优化

利用单因素试验和响应面设计相结合,对黏红酵母产油脂培养基进行了优化。单因素试验得到初步发酵培养基成分为葡萄糖、蛋白胨、KH2PO4。经响应面优化发现,当发酵培养基中葡萄糖含量为73.40g/L,蛋白胨含量为1.06 g/L,KH2PO4含量为3.56 g/L时,油脂产量的理论预测值可达到3.49 g/L,比优化前提高了13%。气相分析其油脂组成,多不饱和脂肪酸质量分数为26.97%。然后又对高产菌株的发酵特性进行研究,在10 d时,生物量和油脂产量达到最高,此时达到发酵终点,生物量为47.98 g/L(菌体湿重),油脂产量达到7.81 g/L。     

红酵母Y-5产类胡萝卜素培养基无机盐组分的优化

为提高红酵母菌株Y-5 发酵产类胡萝卜素的产量,对培养基中无机盐组分进行优化。采用Plackett-Burman试验设计从8 种无机盐中筛选出对提高类胡萝卜素产量具有显著效应的无机盐组分KH₂PO₄、MgSO₄ 和NaCl。通过Box-Behnken 设计及响应面分析确定其质量浓度为KH₂PO₄ 0.58g/L、MgSO₄ 0.49g/L、NaCl 0.28g/L 时,菌株的类胡萝卜素产量达到14.51mg/L,与未添加无机盐组分培养基相比,类胡萝卜素产量提高了25.09%。     

Use of waste chicken feathers as peptone for production of carotenoids in submerged culture of <Emphasis Type=Italic>Rhodotorula glutinis</Emphasis> MT-5

Peptones are one of the most expensive constituents of fermentation media. The present study was performed to prepare the peptone from waste chicken feathers through acid hydrolysis and to investigate the usability of this peptone as substrate for biomass and carotenoid production by Rhodotorula glutinis MT-5. Chicken feather peptone (CFP) was found to be rich in ash (42.1 g/100 g), protein (55.8 g/100 g) and mineral contents. The ability of CFP to support biomass and carotenoid production in the yeast was comparable to those of two commercial peptones (Tryptone peptone = TP and Fish peptone = FP). The optimum concentration of CFP was found to be 8 g/L for both biomass and carotenoid production. Adding 8 g/L CFP to the medium increased carotenoid and biomass production about 53 and 36% compared to control, respectively. At the end of the fermentation, the maximum biomass (14.2 g/L) and carotenoid (92 mg/L) concentrations were achieved with CFP. Moreover, the maximum carotenoid yield (6.47 mg/g) was reached in CFP medium. This study showed for the first time that waste chicken feathers could be effectively used as a novel carotenoid production substrate for R. glutinis.     

马铃薯渣生料同步糖化发酵生产乙醇工艺研究

采用生料同步糖化发酵法,将马铃薯提取淀粉后的废渣进行发酵制备乙醇,对各影响因素进行了探讨,获得了最佳发酵工艺条件.结果显示:适宜发酵条件为水料比3.5∶1.0、初始pH4.5、酵母接种量0.4％、发酵温度32℃、糖化酶添加量160U/g,α-淀粉酶添加量10U/g、纤维素酶添加量10U/g、原料粒度0.40mm.     

响应面法优化马铃薯渣生料同步糖化发酵生产乙醇工艺

采用生料同步糖化发酵法,将马铃薯废渣发酵生产乙醇,对各个影响因素进行了研究,并通过响应面法优化发酵工艺。结果显示:最佳发酵条件为水料比3.5∶1、初始pH值4.5、酵母接种量0.42%、发酵温度32℃、糖化酶添加量165U/g、α-淀粉酶添加量11U/g、纤维素酶添加量12U/g、原料粒度0.40mm。该方法工艺简单,能耗小,成本低,可用于马铃薯废渣工业化处理。     

废弃植物油亚临界水解制取混合脂肪酸及其动力学研究

以废弃植物油为原料,用亚临界水解法制备混合脂肪酸,研究混合脂肪酸的制备条件及其反应动力学。结果表明,废弃植物油在亚临界水中的适宜反应条件为:反应温度280℃,反应时间30 min,油水体积比为1:3.5,转化率最高达98.1%。废弃植物油在亚临界水中的水解反应平均反应级数为n=1.123 89,活化能E_a=70.87 kJ/mol,频率因子A=1.770 6×10~5,动力学模型为-dc_A/dt=1.770 6×10~5e~(-70.87/RT)C_A~1.123.89。     

Production of α‐amylase by Aspergillus oryzae As 3951 in solid state fermentation using spent brewing grains as substrate

BACKGROUND: The optimisation of nutrient levels for the production of α‐amylase by Aspergillus oryzae As 3951 in solid state fermentation (SSF) with spent brewing grains (SBG), an inexpensive substrate and solid support, was carried out using response surface methodology (RSM) based on Plackett–Burman design (PBD) and Box–Behnken design (BBD). RESULTS: In the first optimisation step a PBD was used to evaluate the influences of related factors. Corn steep liquor, CaCl₂ and MgSO₄ were found to be the most compatible supplements to the substrate of SBG and influenced α‐amylase activity positively. In the second step the concentrations of these three nutrients were optimised using a BBD. The final concentrations (g/g dry substrate basis) in the medium optimised with RSM were 1.8% corn steep liquor, 0.22% CaCl₂ and 0.2% MgSO₄ · 7H₂O using SBG as the solid substrate. The average α‐amylase activity reached 6186 U g^?1 dry substrate under the optimised conditions at 30 °C after 96 h. Under the optimised conditions of SSF an approximately 17.5% increase in enzyme yield was observed. CONCLUSION: SBG was found to be a good substrate for the production of α‐amylase by A. oryzae As 3951 under SSF. Copyright © 2007 Society of Chemical Industry     

Production of R-(+)-α-terpineol by the biotransformation of limonene from orange essential oil,using cassava waste water as medium

The use of two agro-residues (liquid cassava waste and orange essential oil) in the biotransformation of R-(+)-limonene was investigated. The main components of orange essential oil were determined by GC–MS and R-(+)-limonene was shown to be the predominant constituent, accounting for more than 94% of the total content. Cassava wastewater proved to be a suitable substrate for mycelial growth, leading to good, rapid growth with all the fungal strains tested, reaching 29.4 g/l (dry weight) after 3 days of growth (Penicillium sp. 2025). The best R-(+)-α-terpineol yields were achieved when the strains were grown in cassava media and the mycelia then transferred to a new flask containing mineral medium and orange essential oil as the sole C- and energy source. One of the strains tested, Fusarium oxysporum 152B, converted R-(+)-limonene to R-(+)-α-terpineol, yielding nearly 450 mg/l after 3 days of transformation. Growth in the presence of a solution of 1% orange essential oil in decane did not increase the transformation yields.