重离子辐照酿酒酵母及其产酒能力初步研究

通过利用能量为100MeV/u C12的重离子束对酿酒酵母进行辐照处理,再经筛选得到1株产酒能力高的菌株,结果表明,突变株表现出较好的遗传性状,对温度的耐受性也有所提高,利用诱变菌株进行发酵,酒精度达到10.3°。     

混菌发酵啤酒糟开发含β-胡萝卜素饲料的研究

研究采用毛柄金钱菌和枯草芽胞杆菌分别预处理啤酒糟后,再接种粘红酵母31229共发酵啤酒糟开发富含β-胡萝卜素的混菌饲料。结果表明：毛柄金钱菌、枯草芽胞杆菌和粘红酵母31229在啤酒糟中能够分别生长良好,粘红酵母31229能用啤酒糟等丰富而廉价的原料作为碳源生产β-胡萝卜素;以纤维素酶活力较强的毛柄金钱菌处理啤酒糟培养基5 d,发酵液进行一次灭菌后再接种粘红酵母31229,4 d后所得的粘红酵母31229菌体生物量和β 胡萝卜素分别达到13.10g/L和62.64 μg/（g干菌体）。     

混菌发酵啤酒糟开发富含β-胡萝卜素饲料的研究北大核心

研究采用毛柄金钱菌和枯草芽胞杆菌分别预处理啤酒糟后,再接种粘红酵母31229共发酵啤酒糟开发富含β-胡萝卜素的混菌饲料。结果表明:毛柄金钱菌、枯草芽胞杆菌和粘红酵母31229在啤酒糟中能够分别生长良好,粘红酵母31229能用啤酒糟等丰富而廉价的原料作为碳源生产β-胡萝卜素;以纤维素酶活力较强的毛柄金钱菌处理啤酒糟培养基5d,发酵液进行一次灭菌后再接种粘红酵母31229,4d后所得的粘红酵母31229菌体生物量和β-胡萝卜素分别达到13.10g/L和62.64μg/(g干菌体)。     

黏红酵母离子注入诱变及其发酵产生β- 胡萝卜素条件的研究

利用低能N+ 注入黏红酵母高压突变株G-39,经筛选获得高产β- 胡萝卜素的离子诱变株GL-5,其β- 胡萝卜素产量由出发菌株的9.64mg/L 提高到17.36mg/L,增加了80.08%。通过均匀设计试验法,初步确定了诱变株GL-5 的β- 胡萝卜素发酵最适条件(葡萄糖40g/L、蛋白胨30g/L、酵母膏10g/L、番茄汁3ml/L、核黄素0.5mg/L、初始pH6.0、摇瓶装量50ml/250ml、接种量50ml/L),使其β- 胡萝卜素产量进一步由17.36mg/L 提高到34.21mg/L,比对照增加了98.09%。这表明,离子诱变株GL-5 是一株优良的高产β- 胡萝卜素突变株,离子注入对该菌种具有良好的诱变效果。     

~(12)C~(6+)辐照环境下酵母高产β-葡聚糖菌株筛选及条件优化研究

利用80 MeV/u能量的~(12)C~(6+)重离子束辐照处理面包酵母(Saccharomyces cerevisiae),经过发酵培养筛选,获得了9株高产β-葡聚糖的突变菌株,其中突变菌株YH-11的β-葡聚糖产量高达1.4833mg/mL,比出发菌株YS-00β-葡聚糖产量高73%。不同培养基条件碳源、氮源及金属离子浓度的改变对酵母菌β-葡聚糖产出能力影响的发酵实验表明,最佳培养条件是2%葡萄糖、1%牛肉膏,以及0.1%的KH_2PO_4和Mg_2SO_4,在此实验条件下,突变菌株YH-11的β-葡聚糖产量高达1.4833 mg/mL,较出发菌株YS-00产量提高了1.73倍。实验证明,重离子辐照技术是一种高效的微生物诱变育种手段,在未来的微生物发酵工业应用中具有广阔发展前景。     

奶牛源鼠李糖乳杆菌的12C6+重离子束诱变选育

本研究利用中科院重离子加速器释放的12C6+重离子束作为辐射诱变源,以酸斑值（HC）和抑菌圈值为指标,对鼠李糖乳杆菌JF12-1进行功能性诱变。通过致死率和正负突变率确定诱变的最佳辐照剂量;对最佳辐照剂量下的突变菌株利用酸斑法进行初筛,抑菌圈法复筛,而后通过连续传代之后检测乳酸含量变化来测定遗传稳定性,并对遗传稳定菌株进行16S rDNA测序,定位其突变位点。结果显示辐照剂量为300 Gy时,致死率为79.86%,正突变率为30.33%,负突变率为5.38%,确定为最佳诱变剂量;酸斑法初筛最佳诱变剂量下的突变菌株,得到20株HC值较原始野生菌株提高25%以上的突变株;抑菌法复筛得到8株体外抑菌性较原始野生菌株提高15%以上的菌株;遗传稳定性测定发现这8株突变乳酸菌株产乳酸稳定性良好;16S rDNA测序发现原始野生型菌株JF12-1的可能突变位点不在16S rRNA基因上,促使其产酸和抑菌性能增强的突变位点可能发生在其他基因区段。利用12C6+重离子束成功诱变选育出了高产乳酸及体外抑菌性优良的功能性鼠李糖乳杆菌稳定株,为下一步深入开发该菌株提供了较好的理论基础和应用依据。     

重离子诱变对木聚糖酶产生菌产酶的影响

以1株由青藏高原牦牛粪中分离出的链霉菌为出发菌株,该菌株在发酵培养基中能产生胞外木聚糖酶(3 227.346 U/mL)。以此菌株为出发菌株,对其进行重离子辐照诱变处理,从大量突变株中筛选出木聚糖酶高产菌株SZ10-7,其酶活力达到5 338.42 U/mL,与出发菌株相比较,突变株SZ10-7的酶活力提高了1.65倍。对突变株SZ10-7的发酵条件进行了优化研究,结果表明,该菌株的木聚糖酶活力得到进一步提高,达到5 850.20U/mL,其最适发酵条件为:培养基(g/100 mL)为玉米芯∶麸皮(体积比1∶1)5,酵母膏0.8,K2 HPO4.3H2 O 0.1,MgSO4.7H20 0.5,NaCl 0.3,pH 7.0,培养温度25℃振荡培养时间96 h,实验结果表明,重离子辐照诱变技术是一种有效的微生物诱变育种新技术。     

掷孢酵母类胡萝卜素的提取与鉴定

将一株从草莓果实上分离得到的能够积累类胡萝卜素的掷孢酵母利用二甲基亚砜法进行色素提取,经过薄层层析法（thin layer chromatography,TLC）、分光光度计法及高效液相色谱法（high performance liquidchromatography,HPLC）检测,与粘红酵母标准菌株R.glutinis NBRC 1125T、掷孢酵母标准菌株S. pararoseus CBS0376T及β-胡萝卜素标准品进行对比,结果表明：掷孢酵母野生型NGR主要积累3 种色素,分别为红酵母红素、圆酵母素和β-胡萝卜素,其中圆酵母素和β-胡萝卜素及其异构体（推测为13-顺式-β-胡萝卜素）含量最多（分别约为653.22 μg/g和635.10 μg/g）,红酵母红素积累量较少,约为150.37 μg/g。野生型NGR的紫外诱变突变株Y9为高产β-胡萝卜素突变株,β-胡萝卜素积累量可占总类胡萝卜素比例的54%,W1为不产β-胡萝卜素,红酵母红素和圆酵母素积累量减少的粉色突变株,W4为不产色素的白化突变株。在常规酵母培养基培养下,野生型NGR积累总色素含量可达1 438.69 μg/g。     

低能离子注入对产胡萝卜素红酵母NR06的诱变效应研究

分别以红酵母NR06和其原生质体为研究对象,通过注入生命必需元素N 以期获得高产类胡萝卜素突变株.结果表明,原生质体在各种注入剂量下的存活率几乎均为零,说明在所实验的条件下原生质体不宜用于离子注入诱变育种.但对红酵母细胞直接诱变时,当注入剂量为12×1014N /cm2时,获得一株高产类胡萝卜素突变株L15,其β-胡萝卜素产量可达8.0mg/L,比出发菌株NR06提高了34.5%,并且该高产菌株遗传性能较为稳定.     

高产胡萝卜素红酵母突变株的选育

以红酵母为初发菌株,经等离子体诱变处理,选育出高产胡萝卜素的红酵母突变株,初步确定了促使胡萝卜素质量提高的适宜培养基组成及培养条件,经９６ｈ发酵后,菌体胡萝卜素含量达５．１０ｕｇ／ｍｌ比出发菌株提高５９．４％。     

OPTIMIZATION OF CAROTENE RECOVERY FROM HYDROLYZED PALM OLEIN IN ADSORPTION COLUMN CHROMATOGRAPHY USING RESPONSE SURFACE METHODOLOGY

Response Surface Methodology (RSM) for optimization of carotene recovery from hydrolyzed palm olein (HCPOlein) in adsorption chromatography was carried out. The level and interaction of three independent variables was investigated: column temperature (50 to 60C), oil loading (25 to 200 g), and mobile phase flow rate (6 to 60 mL/min). Based on the response as percentage of carotene recovery from 50 g of HP-20 adsorbent, the optimum conditions were achieved at 200 g of oil loading, column temperature at 55C, and flow rate at 33 mL/min. Up to 98% of carotene recovery was obtained under these conditions. Interaction of oil-oil, oil-flow rate and flow rate-flow rate could enhance the percentage of carotene recovery. However, oil and flow rate as single factors could significantly reduce percentage of carotene recovery. Oil loading as a single factor could positively influence the amount of carotene adsorbed. However, flow rate as a single factor and oil-oil interaction could negatively influence the amount of carotene adsorbed. The mean of difference (MD) of the experimental and predicted data for percentage of carotene recovery and the amount of carotene adsorbed were very small, −0.0067 and 0.0133, respectively. The probability (P) value showed no significant lack-of-fit for both equations in this model.     

重离子束辐照选育高产细菌素植物乳杆菌

采用重离子束12C6+对产细菌素植物乳杆菌Lp1进行辐照选育,分析比较了不同辐照剂量下致死率和突变率,并通过双层琼脂扩散法筛选高产细菌素突变菌株。在辐照剂量300 Gy时,出发菌株植物乳杆菌Lp1的致死率和正突变率分别为86.3%和28.28%。在300 Gy辐照菌悬液中,分离筛选出高产细菌素突变菌株Lp092、Lp085,以大肠埃希氏菌为指示菌抑菌圈直径比出发菌株Lp1分别扩大了20.64%、19.36%,以金黄色葡萄球菌为指示菌抑菌圈直径比出发菌株Lp1分别扩大了17.16%、14.14%,经过连续传代5次实验,2株菌株Lp092、Lp085均具有良好的产细菌素遗传稳定性。     

利福霉素产生菌育种及发酵罐放大试验研究

用紫外和氯化锂复合诱变利福霉素产生菌,得到发酵效价为6837 u/mL的菌株A22-04,比初始菌株提高36.5%。对该菌株进行发酵罐放大试验,10 L罐发酵效价为7234 u/mL,发酵时间为120 h,比对照菌株缩短了12 h;30 m~3生产罐的发酵效价为6497u/mL,发酵时间也略有缩短。     

以黑曲霉生产面包品质改良复合酶的研究

从粮食样品中分离并筛选出 1株可同时产生α 淀粉酶 (FAA)和葡萄糖氧化酶(GOD)的黑曲霉菌株。经试验表明 ,该菌株在适宜的条件下可稳定产生FAA 2 0 0u/mL以上 ,GOD 1 5u/ g以上。产生的 2种复合酶在pH 6～ 7下可表现最高酶活力 ,酶作用的适宜温度为 3 0～ 40℃ ,40℃下保温 3 0min酶活降低 5 0 %左右 ,在 60℃以上 2种酶均基本无活性 ,适宜用作面包制作的品质改良剂     

Chemical, Physical, and Sensory Properties of a Sweet Potato French-Fry Type Product During Frozen Storage

Chemical, physical, and sensory properties of a sweet potato Frenchfry type product were determined after 0, 3, 6, 9, and 12 months frozen storage. Analyses included measurements of dry matter, sugars, alcohol insoluble solids, carotene, vitamin C, color, texture and sensory panel scores for color, flavor and texture. Few changes were observed except for an appreciable loss (58%) in vitamin C and an apparent increase in carotene (27%). A partial drying treatment before freezing increased the rate of ascorbic acid loss. For the fried product, no appreciable storage-induced changes were noted in the sensory scores for color, flavor and texture thus indicating that the product had good stability in frozen storage.     

RECOVERY OF PALM CAROTENE FROM PALM OIL AND HYDROLYZED PALM OIL BY ADSORPTION COLUMN CHROMATOGRAPHY

Crude palm oil and crude palm olein were hydrolyzed with lipase from Candida rugosa to produce a free fatty acid (FFA) rich oil. The percentages of FFA produced and carotene degradation after the hydrolysis process were determined. The palm oil and hydrolyzed palm oil were subsequently subjected to column chromatography. Diaion HP-20 adsorbent was used for reverse phase column chromatography at 50C. Isopropanol or ethanol, and n-hexane were used as the first and second eluting solvents, respectively. The objective of hydrolyzing the palm oil was to produce more polar FFA-rich oil in order to enhance the nonpolar carotene bind to the nonpolar HP-20 adsorbent in the column chromatography process. Hydrolyzing palm oil with lipase from Candida rugosa gave 30- and 60-fold, respectively, of FFA in the crude palm oil and crude palm olein in 24 h at 50C. Approximately, 15.56 and 17.48% of carotene degraded in crude palm oil and crude palm olein, respectively. For column chromatography, using isopropanol or ethanol as the first eluting solvent, unhydrolyzed oil and hydrolyzed oil showed the carotene recovery infraction two (carotene-rich fraction) of about 36–37 and 90–96%, respectively. Over 90% of carotene recovery was obtained from     

产过氧化氢酶的乳酸菌的筛选和产酶条件的研究

从不同生态环境分离到21株产酸菌,从中筛选出一株产乳酸力强、产胞外过氧化氢酶活力较高的菌株TL012,其产酶最适温度为38℃,初始培养始pH6、培养50小时,在脱脂奶粉培养基中产酶可达98.40μ/ml。     

干制和保藏过程中枸杞β-胡萝卜素保存率的研究

研究了枸杞脱水干制过程中热烫时间和热烫温度、预处理、以及干制工艺条件对β－胡萝卜素保存率的影响，并对干制工艺条件进行了优化组合，优化组合条件如下：枸杞鲜果蒸汽热烫２分钟，用０．３％Ｎａ２ＳＯ３＋０．０３％Ｖｃ＋０．０４％ＥＤＴＡ－Ｎａ２溶液预处理１ｈ，在５０℃２０ｈ、６０℃１２ｈ、６５℃１１ｈ的干制工艺条件下进行脱水干制，β－胡萝卜素保存率可达８９．１％。此外，还探讨了包装材料颜色及保藏温度对枸杞干果β－胡萝卜素保存率的影响，结果表明：保藏温度对β－胡萝卜素保存率无显著影响，而包装材料的颜色对β－胡萝卜素保存率有显著的影响。