Batch and Continuous Production of Lactic Acid from Beet Molasses by Lactobacillus delbrueckii IFO 3202

Process variables were optimized for the production of lactic acid from pretreated beet molasses by Lactobacillus delbrueckii IFO 3202 for batch and continuous fermentations. In the batch fermentation, maximum yields (95·4% conversion, 77·1% effective) and maximum lactic acid volumetric productivity (4·83 g dm⁻³ h⁻¹) was achieved at 45°C, pH 6·0, 78·2 g dm⁻³ sugar concentration with 10 g dm⁻³ yeast extract. Various cheaper nitrogen sources were replaced with yeast extract on equal nitrogen bases in batch fermentation. Of all the nitrogen sources tested, yeast extract yielded the highest and malt sprouts yielded the second highest level of lactic acid. In the continuous fermentation, maximum lactic acid (4·15%) was obtained at a dilution rate of 0·1 h⁻¹. Maximum volumetric lactic acid productivity (11·20 g dm⁻³ h⁻¹) occurred at D = 0·5 h⁻¹ dilution rate. © 1997 SCI.     

Production of lactic acid from beet molasses by calcium alginate immobilized Lactobacillus delbrueckii IFO 3202

Lactic acid was produced from pretreated beet molasses by the homofermentative organism Lactobacillus delbrueckii subsp delbrueckii IFO 3202 entrapped in calcium alginate gel using batch, repeated batch and continuous fermentation systems. In batch fermentation studies successful results were obtained with 2.0–2.4 mm diameter beads prepared from 2% sodium alginate solution. The highest effective yield (82.0%) and conversion yield (90.0%) were obtained from substrate concentrations of 52.1 and 78.2 g dm⁻³ respectively. The gel beads produced lactic acid for 14 consecutive batch fermentations without marked activity loss and deformation. In the continuous fermentation, the highest lactic acid (4.22%) was obtained at a dilution rate of 0.1 h⁻¹ while the highest productivity (13.92 g dm⁻³ h⁻¹) was obtained at a dilution rate of 0.4 h⁻¹. © 1999 Society of Chemical Industry     

Lactic Acid Production by Lactobacillus paracasei 168 in Discontinuous Fermentation Using Lucerne Green Juice as Nutrient Substitute

The aim of this study was the utilization of lucerne green juice (LGJ), obtained in 2005 and 2008, as nutrient substitute in lactic acid fermentation using Lactobacillus paracasei 168, in a discontinuous fermentation process with the addition of 55 g/L glucose and 15 g/L yeast extract. The LGJ after pressing fresh green mass contains a series of nitrogen‐containing compounds and inorganic salts that are essential for cell growth. The strain used, L. paracasei 168, achieved at 40.5 °C and pH 6.0 a maximum productivity of up to 2.56 g L^–1 h^–1 and a lactic concentration close to 45.97 g/L in trial A (LGJ 2008/glucose), 2.19 g L^–1 h^–1, 47.23 g/L in trial B (LGJ 2005/glucose), 2.93 g L^–1 h^–1, 42.27 g/L in trial C (LGJ 2008/glucose/yeast extract), and 2.68 g L^–1 h^–1, 47.33 g/L in trial D (LGJ 2005/glucose/yeast extract). Addition of yeast extract in trials C and D induced faster growth of L. paracasei 168. Lactate yields of about 87 % were obtained in all trials. The lactic acid formed was the optically pure L‐(+)‐isomer at up to 97 % in trial B. Pearson's analysis showed that the level of lactic acid in the control trial was positively and significantly correlated with trial A (r² = 0.9899), B (r² = 0.9582), C (r² = 0.9901), and D (r² = 0.9938), with p <0.0001.     

乳酸菌发酵甘蔗糖蜜产乳酸的培养条件优化

乳酸是有广泛应用的有机酸,廉价原料是降低乳酸生产成本的重要因素。以实验室前期筛选的植物乳杆菌sy4为出发菌株研究了利用甘蔗糖蜜生产乳酸的培养条件。在确定发酵温度和初始pH后,通过Plackett-Burman实验和中心复合实验优化乳酸发酵条件。结果表明：植物乳杆菌sy4乳酸发酵的最适条件为温度32℃、60h、初始pH 6.5;Plackett-Burman实验表明酵母提取物、糖蜜和碳酸钙是影响乳酸产量的主要因素;中心复合实验得到三因素的最优组合为：酵母提取物13.19g/L、糖蜜476.63g/L和碳酸钙134.82g/L,确定了最适发酵培养基。在此条件下乳酸产量为（145.53±1.24） g/L,与模型预测值147.23g/L接近。本研究为以甘蔗糖蜜为原料生产乳酸提供了技术支持。     

Improved Ethanol Production by Saccharomyces cerevisiae with EDTA,Ferrocyanide and Zeolite X Addition to Sugar Beet Molasses

The influence of ethylenediaminetetra acetic acid (EDTA), potassium ferrocyanide and zeolite X on ethanol production from sugar beet molasses by Saccharomyces cerevisiae was studied. For all of the three substances used, the effect was more pronounced when added to the fermentation medium rather than to the growth medium; 1·9 mmol dm⁻³ potassium ferrocyanide caused an increase in the final ethanol concentration of about 16·4% and 47·5% with respect to control culture on addition to growth and fermentation media respectively. The greatest stimulation in product yield was obtained with zeolite X introduced during the fermentation stage; 8·0 g dm⁻³ zeolite X increased ethanol concentration by 53·3%. © 1997 SCI.     

发酵液中乳酸的电渗析法分离

采用电渗法分离发酵液中低浓度乳酸,考察了电渗析器的操作条件对极限电流密度和乳酸电年速率的影响,并分别用修正的Ｗｉｌｓｏｎ公式和乳酸电渗析速率方程描述了它们之间的关系。     

Production of L‐lactic acid by Lactobacillus delbrueckii in chemostat culture using an ion exchange resins system

L ‐Lactic acid production from beet molasses by Lactobacillus delbrueckii CECT 286 in a continuous fermenter‐ion exchange resins system has been investigated and compared with that observed in a conventional chemostat. The principle of this method is to remove the lactate during the course of fermentation as it is formed by adsorption to an anion exchange resin (Amberlite IRA‐420) in the carbonate form and to overcome its inhibitory effects on lactic acid bacteria by maintaining low lactate concentrations in the medium. Ammonium lactate was formed by percolating ammonium carbonate solution through this resin and it was converted to lactic acid by treatment with a cation exchange resin (Amberlite IR‐120) in hydrogen form. Compared with a conventional chemostat, this fermentation–ion exchange resins system enhanced the fermentation, controlled the pH, and showed the remarkable effect of increasing the yields of lactic acid from sucrose and biomass from sucrose due to the complete utilization of sucrose. © 1999 Society of Chemical Industry     

聚乙烯醇-海藻酸钙作为德氏乳酸杆菌包埋剂的研究

以德氏乳酸杆菌为考察对象,应用响应面分析法(RSM)对聚乙烯醇-海藻酸钙凝胶配比进行优化研究.结果表明,制备PVA-海藻酸钙复合载体的最佳条件是PVA、海藻酸钠和氯化钙的质量分数分别为6.64%、1.29%和1.97%,固化交联时间为6.48 h,预测乳酸发酵72 h的产量为112.79 g/L.经过120 d,40批次的发酵验证,结果与预测值相符,且乳酸发酵72 h产量比游离细胞发酵平均提高了56%.     

Kinetics of growth and lactic acid production from whey permeate by Lactobacillus helveticus

Batch fermentation kinetics of Lactobacillus helveticus were examined in detail. The nature of the culture medium had a significant effect on the product synthesis mechanism. In a glucose synthetic medium, lactic acid produced by the non-growth-associated mechanism was less than that by the growth-associated mechanism. In a lactose synthetic medium, the contribution of both mechanisms was approximately equal at the end of fermentation. In the whey-yeast extract permeate medium, the contribution by the non-growth-associated mechanism was superior to that of the growth-associated mechanism. Temperature and pH also influenced the relative contribution of the two mechanisms on the total production of lactic acid in whey-yeast extract permeate medium. Under optimal conditions for temperature and pH, the contribution of non-growth-associated product formation was the highest among all temperatures, and the lowest among all pH's. The ATP concentration-biomass concentration relationship in the batch fermentation process could be roughly approximated by a Luedeking-Piret-like equation.     

废糖蜜-硫酸溶液中软锰矿的浸出动力学

用收缩芯模型研究了硫酸介质中废糖蜜还原浸出软锰矿的动力学,考察了软锰矿粒度、反应温度、浸出时间、硫酸浓度和废糖蜜浓度对锰浸出速率的影响. 结果表明,提高反应温度、硫酸浓度、废糖蜜浓度和减小软锰矿颗粒的初始平均半径,均可提高锰的浸出速率. 废糖蜜还原浸出软锰矿属界面化学反应控制,表观活化能为45.6 kJ/mol,硫酸和废糖蜜的反应级数分别为0.52及0.28.     

衣康酸发酵及动力学模型

研究了土曲霉在１０Ｌ搅拌罐和２００Ｌ气升罐中分批发酵生产衣康酸的过程．搅拌罐和气升罐中衣康酸最终浓度分别达到８０．１和８５．１ｇ／Ｌ,对初糖的转化率分别为５０％和５６．７％．同时,对衣康酸发酵建立了一个包括菌体生长、底物消耗、产物形成的动力学模型,根据实验数据,对动力学参数进行了优化,并且对衣康酸合成的动力学机制进行了讨论．     

钨酸铅光催化降解糖蜜酒精废水的研究

糖蜜酒精废水是一种难降解的有机废水,主要成分为焦糖等色素类物质.利用沉淀法制备了PbwoJ光催化剂,将其应用于光催化降解糖蜜酒精废水降解反应中,考察了催化剂用量,空气流量,溶液pH值,助氧化剂及光照强度对糖蜜酒精废水脱色率的影响.研究表明,在紫外光辐照下,PbW04能有效地对糖蜜酒精废水进行光催化作用,过程为一级动力学反应.对于经30倍稀释的糖蜜酒精废水,添加4.0 g·L1的PbW04光催化剂,通入126 L.h1的空气,不改变废水的pH值及不添加助氧化剂H2O2的条件下,在300W高压汞灯照射下反应120 min,PbWO4光催化降解糖蜜酒精废水的脱色率为90.2%,COD去除率为78.6%,得到了较好的降解.     

发酵乳酸的特性及发展前景

发酵乳酸可以用作酸味剂、防腐剂、乳化剂,具有营养性、安全性、对环境友好性,因此,可以用来加工成聚乳酸塑料,替代一次性塑料袋、快餐盒、地膜等;还可以用在食品中调味;做补钙制剂等。我国有丰富的发酵乳酸原料,随着世界市场对发酵乳酸需求量的增加,发酵乳酸在我国具有广阔的市场。     

发酵液中乳酸的盐析萃取

研究了一种利用盐析萃取法分离发酵液中乳酸的新方法. 通过系统考察乳酸在不同盐析萃取体系中的分配规律,发现K2HPO4-甲醇和K2HPO4-乙醇体系适合分离发酵液中的乳酸. 发酵液中乳酸浓度为167 g/L时,采用25%(w) K2HPO4-26%(w)甲醇盐析萃取体系,乳酸的分配系数和回收率分别为4.01和86.0%;采用14%(w) K2HPO4-30%(w)乙醇盐析萃取体系,乳酸的分配系数和回收率分别为3.23和90.6%. 此时上相中残余葡萄糖、菌体和可溶性蛋白的去除率分别达67.3%, 100%和85.9%.     

甜菜糖蜜发酵废液中提取甜菜碱新工艺研究

研究了采用三段离子交换法从甜菜糖蜜发酵废液中提取甜菜碱的工艺条件和影响因素。三段交换分别使用D31 4、D0 0 1及 0 0 1× 7等苯乙烯型离子交换树脂。第一段交换使脱色、脱盐和除杂同时进行 ,免除了活性炭脱色过程。确定了第二段脱盐交换以pH =3为终点 ,使甜菜碱与金属离子彻底分离。第三段为吸附纯化甜菜碱 ,使用 c(HCl) =1 4mol/L为洗脱剂 ,直接制取了盐酸甜菜碱 ,并使洗脱与树脂再生同时进行 ,简化了工艺操作。所得产品纯度达 98%以上 ,收率(对甜菜 )达 90 %以上。     

糖蜜酒精废液中大分子焦糖色素模拟物浸出软锰矿的动力学

用收缩芯模型研究了糖蜜酒精废液中大分子焦糖色素在硫酸介质中还原浸出软锰矿的动力学,考察了软锰矿粒度、反应温度、浸出时间、硫酸浓度和焦糖色素浓度对锰浸出速率的影响.结果表明锰浸出速率随反应温度、硫酸浓度、焦糖色素浓度的增加和软锰矿粒径的减小而增加.糖蜜酒精废液中大分子焦糖色素还原浸出软锰矿属固体产物层扩散控制,表观活化能...     

TRPO－磺化煤油萃取乳酸的影响因素

报导了萃取发酵Ｌ－乳酸中的萃取和反萃取行为的研究。结果表明，在萃取过程中，无机盐（ＭｇＳＯ４、ＺｎＳＯ４、ＫＨ２ＰＯ４）、乳酸钙、葡萄糖和溶液初始乳酸的浓度均对分配比ＤＬａ有明显的影响；并对９０℃热水的反萃取进行了研究。反分配比Ｄ′Ｌａ随有机相初始酸浓的增加而逐渐下降；还对萃取和反萃取机理作了初步的探索     

复合乳酸菌发酵生产天然鲜奶香基的研究

通过吖啶橙诱变提高乳酸菌的脂肪酶和蛋白酶活性,结合感官评定发酵乳风味,筛选得到了具有产香潜力的7株乳酸菌突变菌。组合各株产香菌共发酵,得到了一个能产生鲜奶香基的菌株组合。该组合在以蔗糖-葡萄糖（2∶1）为碳源、添加0.5%柠檬酸铵的牛乳产香培养基中,42℃条件下连续发酵菌株La2、Lc1和St2 12 h,发酵液均质后能作为鲜奶香基直接应用。