Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

BACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions. RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO₃ had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g^?1 dried food waste, a protease activity of 2.12 U g^?1 dried food waste, a temperature of 29.31 °C and a CaCO₃ concentration of 62.67 g L^?1, which resulted in a maximum lactic acid concentration of 98.51 g L^?1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation. CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry     

比较基因组揭示广西酸菜乳杆菌碳水化合物活性酶谱

微生物中的碳水化合物活性酶(carbohydrate active enzymes,CAZymes)具有降解植物组织的作用,相对于真菌,目前对于乳杆菌的CAZymes研究还比较少.该研究从广西酸菜中筛选获得了3株产CAZymes的乳杆菌,并通过二代测序技术比较其编码基因.16S rRNA测序结果表明3株乳杆菌分别是La...     

Lactobacillus sakei MJM60958 as a Potential Probiotic Alleviated Non-Alcoholic Fatty Liver Disease in Mice Fed a High-Fat Diet by Modulating Lipid Metabolism,Inflammation, and Gut Microbiota

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease with a rapidly increasing number of cases worldwide. This study aimed to evaluate the effects of Lactobacillus sakei MJM60958 (MJM60958) on NAFLD in vitro and in vivo. In in vitro tests, MJM60958 significantly inhibited lipid accumulation by 46.79% in HepG2 cells stimulated with oleic acid and cholesterol (OA-C). Moreover, MJM60958 showed safe and probiotic characteristics in vitro. In the animal study, MJM60958 administration in a high-fat diet-induced NAFLD mouse model significantly reduced body weight and liver weight, and controlled aspartate aminotransferase (ALT), aspartate transaminase (AST), triglyceride (TG), urea nitrogen (BUN), and uric acid (UA) levels in the blood, which are features of NAFLD. Further, treatment with MJM60958 also reduced steatosis scores in liver tissues, serum leptin and interleukin, and increased serum adiponectin content. Moreover, administration of MJM60958 resulted in a significantly decreased expression of some genes and proteins which are related to lipid accumulation, such as fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and sterol regulatory element-binding protein 1 (SREBP-1), and also upregulated genes and protein expression of lipid oxidation such as peroxisome proliferator-activated receptor alpha (PPARα) and carnitine palmitoyltransferase 1a (CPT1A). Administration of MJM60958 increased the relative abundance of specific microbial taxa such as Verrucomicrobia, which are abundant in non-NAFLD mice, and reduced Firmicutes, which are a major group in NAFLD mice. MJM60958 affected the modulation of gut microbiota and altered the strain profile of short-chain fatty acids (SCFAs) production in the cecum by reduced lactic acid and enhanced acetic acid production. Overall, MJM60958 showed potential as a probiotic that can prevent and treat NAFLD.     

X射线对嗜热乳杆菌产L-乳酸的选育研究

为了获得更适于工业生产的产L-乳酸菌株,提高生产效率。本文以X射线对嗜热乳杆菌（Lactobacillus thermophilus）进行诱变处理,通过碳酸钙-溴甲酚紫平板初筛结合摇瓶复筛的方法,最终获得稳定高产的突变菌株。结果表明:经X射线诱变得到的突变菌株SR7,平均发酵产酸量为22g/L,比原菌株产量提高了15.04%,且经过多次重复实验表明该菌株具有良好的遗传稳定性。      

混合菌种发酵生产低酸度川味香肠的加工工艺

将植物乳杆菌、戊糖片球菌和葡萄球菌接种到川味香肠中,采用单因素实验和正交实验对低酸度川味香肠的加工工艺进行优化。结果表明,发酵期最佳工艺条件为:发酵温度20℃,发酵时间12h,葡萄糖添加量0.10%,发酵相对湿度75%;成熟期最佳工艺条件为:成熟温度13℃,成熟时间4d,成熟相对湿度60%。最终得到低酸度的川味香肠p H5.50,感官评分为92分,产品酸味适中,麻辣爽口,具有传统四川香肠的特有风味。      

Lactobacillus pentosus MJM60383 Inhibits Lipid Accumulation in Caenorhabditis elegans Induced by Enterobacter cloacae and Glucose

Gut microbiota are known to play an important role in obesity. Enterobacter cloacae, a Gram-negative bacterium, has been considered a pathogenic bacterium related to obesity in the gut. In this study, we established an obesity model of C. elegans by feeding E. cloacae combined with a high glucose diet (HGD), which significantly induced lipid accumulation. An anti-lipid mechanism study revealed that the fatty acid composition and the expression level of fat metabolism-related genes were altered by feeding E. cloacae to C. elegans under HGD conditions. Lactic acid bacteria that showed antagonistic activity against E. cloacae were used to screen anti-obesity candidates in this model. Among them, L. pentosus MJM60383 (MJM60383) showed good antagonistic activity. C. eleans fed with MJM60383 significantly reduced lipid accumulation and triglyceride content. The ratio of C18:1Δ9/C18:0 was also changed in C. elegans by feeding MJM60383. In addition, the expression level of genes related to fatty acid synthesis was significantly decreased and the genes related to fatty acid β-oxidation were up-regulated by feeding MJM60383. Moreover, MJM60383 also exhibited a high adhesive ability to Caco-2 cells and colonized the gut of C. elegans. Thus, L. pentosus MJM60383 can be a promising candidate for anti-obesity probiotics. To the best of our knowledge, this is the first report that uses E. cloacae combined with a high-glucose diet to study the interactions between individual pathogens and probiotics in C. elegans.     

高产酸及耐酸性干酪乳杆菌的诱变筛选

为筛选高产酸及耐酸的干酪乳杆菌菌株,以干酪乳杆菌LC2W为出发菌株,分别对其进行紫外（Ultraviolet,UV）、亚硝基胍（Nitrosoguanidine,NTG）和硫酸二乙酯（Diethyl sulfate,DES）诱变以及人工胃液处理。结果显示,通过0.3 g/L的亚硝基胍处理30 min和紫外线照射30 s后得到的诱变菌株LC2W-NTG-12,LC2W-UV-11表现出高产酸及耐酸性能。相同条件下,出发菌株LC2W和突变菌株LC2W-NTG-12,LC2W-UV-11经24 h发酵后的滴定酸度分别为76.6°T和112.7°T,98.2°T,突变菌株产酸能力分别提高了47.13%、28.20%。当用p H为1.5的酸液处理2 h后,出发菌株和诱变菌株LC2W-NTG-12,LC2W-UV-11的致死率分别为76.44%、52.06%、56.36%,诱变菌株耐酸能力分别提高了24.38%、20.08%。而用0.16%DES处理30 min得到的诱变菌株LC2W-DES-33发酵后的酸度仅比出发菌株提高了14.10%,诱变效果并不明显。说明亚硝基胍诱变可有效提高干酪乳杆菌的产酸及耐酸性能。      

罗伊氏乳杆菌发酵液中具有降胆固醇能力蛋白的分离、纯化和鉴定

罗伊氏乳杆菌DSM122460无细胞上清发酵液（cell-free supernatant,CFS）具有较高的胆固醇移除能力,经初步鉴定有效成分为蛋白质。通过超滤浓缩、硫酸铵分级沉淀、DEAE Sepharose F.F阴离子交换层析进一步对该活性成分进行分离纯化。纯化后,其比活力达到61.6 U/mg,纯化倍数为32.4。经SDS-PAGE检测,样品达到电泳级纯,分子量约为60 ku。通过质谱鉴定初步认定该活性蛋白为一假设蛋白,其功能尚待进一步研究。      

黄芪对嗜酸乳杆菌生长及其产酶活的影响

研究添加不同浓度的黄芪提取液对嗜酸乳杆菌生长及产酶能力的影响,对比在改良的MRS培养基中添加与未添加黄芪提取液对嗜酸乳杆菌的生物量和生长周期的影响,同时测定了嗜酸乳杆菌产β-半乳糖苷酶、葡萄糖氧化酶和淀粉酶的酶活,确定黄芪提取液的最佳添加浓度。结果表明:当添加黄芪提取液浓度为0.032mg/mL时对嗜酸乳杆菌生长有明显的促进作用,且在此浓度下pH达最低值3.88;当添加黄芪提取液浓度为0.016g/mL时,嗜酸乳杆菌产β-半乳糖苷酶、葡萄糖氧化酶和淀粉酶的酶活达到最高值,分别为387.56、14.42、4.4U。      

低聚糖对乳酸菌抗氧化胁迫能力的影响

目的:研究GOS（低聚半乳糖）和XOS（低聚木糖）对乳酸菌（L.bulgaricus Fn009）耐H2O2胁迫能力的影响。方法:利用H2O2建立氧化应激模型,以MTT法（四甲基偶氮唑盐比色法）检测GOS和XOS对乳酸菌存活率影响,以流式细胞技术检测GOS和XOS对乳菌细胞膜完整性的影响,并测定GOS和XOS对乳酸菌抗氧化酶活力和应激蛋白基因表达水平的影响。结果:H2O2胁迫条件下,GOS和XOS干预组乳酸菌存活率提高了1.83～1.96倍,细胞膜完整率分别提高了17%和13%,T-SOD和GSH-Px酶活力均显著上升（p<0.05）,Dnak、GroEL和Gsp65应激蛋白基因的表达水平显著下调（p<0.05）。结论:GOS和XOS能够提高乳酸菌自身的抗氧化活力,降低H2O2胁迫对菌体细胞膜的损伤程度,增强乳酸菌对氧化胁迫的抗性。