以蔗糖为原料明串珠菌发酵生产甘露醇

肠膜明串珠菌CGMCC 1.10327为发酵菌株,质量浓度为2%的蔗糖为底物,采用分批发酵,研究甘露醇的生成。为了优化甘露醇的生成,分别考察了添加5 g/L的葡萄糖、3种盐(K2HPO4、乙酸钠、柠檬酸铵)、不同的初始pH和加入0.2%的CaCO3对产甘露醇的影响。结果表明,葡萄糖的加入有助于提高甘露醇的产量。3种盐(K2HPO4、乙酸钠、柠檬酸铵)对甘露醇的生成有明显的影响,当分别为2 g/L、5 g/L和2 g/L时,甘露醇的产量最高。最佳的初始pH=6。向培养基中加入0.2%的CaCO3,甘露醇的产量明显的降低。     

牛乳中肠膜明串珠菌AR66的降胆固醇抗氧化特性

使用MRS培养基,从新鲜牛乳中分离得到1株生长良好的乳酸菌(AR66),经菌落形态、细胞形态、生化反应实验,发现菌株能产乳酸、革兰氏染色阳性、接触酶阴性。经系统发育分析,确定菌株AR66为肠膜明串珠菌。肠膜明串珠菌AR66具有抗氧化活性,对羟自由基、DPPH和超氧阴离子的清除率与细胞浓度呈正相关。在细胞浓度为5×108CFU/m L时,未破碎细胞对羟自由基、超氧阴离子的清除率高于已破碎细胞的清除率,分别是49.76%和83.33%;已破碎细胞对DPPH自由基的清除率高于未破碎细胞的清除率,为77.09%。菌株AR66还具有清除培养基中44.73%的胆固醇。菌株AR66对我国未来益生菌功能食品的开发具有重要价值。      

牛乳中肠膜明串珠菌AR66的降胆固醇抗氧化特性

使用MRS培养基,从新鲜牛乳中分离得到1株生长良好的乳酸菌(AR66),经菌落形态、细胞形态、生化反应实验,发现菌株能产乳酸、革兰氏染色阳性、接触酶阴性。经系统发育分析,确定菌株AR66为肠膜明串珠菌。肠膜明串珠菌AR66具有抗氧化活性,对羟自由基、DPPH和超氧阴离子的清除率与细胞浓度呈正相关。在细胞浓度为5×108CFU/m L时,未破碎细胞对羟自由基、超氧阴离子的清除率高于已破碎细胞的清除率,分别是49.76%和83.33%;已破碎细胞对DPPH自由基的清除率高于未破碎细胞的清除率,为77.09%。菌株AR66还具有清除培养基中44.73%的胆固醇。菌株AR66对我国未来益生菌功能食品的开发具有重要价值。     

肠膜明串珠菌胞外多糖合成的蛋白组学分析

以高产胞外多糖的肠膜明串珠菌BD3749为材料,通过双向电泳技术分析了产糖过程中的蛋白质组。结果表明,在产糖过程中有131个蛋白发生了明显变化(2倍以上),其中25个蛋白有显著改变(10倍以上)。初步的质谱鉴定表明,其中包含GH70家族的糖基转移酶、丝氨酸/苏氨酸蛋白激酶以及分子伴侣。肠膜明串珠菌胞外多糖的合成是一个复杂的过程,涉及众多基因在蛋白水平的变化。      

High pressure destruction kinetics of Leuconostoc mesenteroides and Saccharomyces cerevisiae in single strength and concentrated orange juice

High pressure (HP) destruction of Leucoonostoc mesenteroides and Saccharomyces cerevisiae in single strength and concentrated orange juice by high hydrostatic pressure treatment was evaluated at selected pressures (100–400 MPa) and holding times (0–120 min) at 20 °C. Kinetic analysis of the microbial survivor data was evaluated based on the biphasic destruction behavior consisting of: (i) an instantaneous pressure kill (IPK) effect due to pressurization–depressurization with no hold-time (pressure-pulse); and (ii) a subsequent semi-logarithmic (first order) destruction during the pressure hold-time. IPK values were enhanced at higher pressure levels and were more pronounced for S. cerevisiae than for L. mesenteroides. During the pressure-hold, as expected, the associated D values (decimal reduction time) decreased with an increase in pressure. However, S. cerevisiae had higher D values, especially in concentrated orange juice, suggesting a higher pressure resistance than L. mesenteroides. The pressure dependency of kinetic parameters was well described by the conventional death time model with associated z_p values (pressure range to result in a decimal change in D values) of 137 and 135 MPa in the single strength orange juice and 251 and 287 MPa in the concentrate, respectively, for L. mesenteroides and S. cerevisiae.     

肠膜明串珠菌肠膜亚种Z_25在苹果酒中发酵特性的研究

从发酵温度、接种量、酒精度、起始苹果酸浓度等方面研究了肠膜明串珠菌肠膜亚种Z25的苹果酸乳酸发酵（MLF）能力,确定了肠膜明串珠菌MLF适宜条件为温度20℃、接种量6%、酒精度10%（v/v）以及起始苹果酸浓度4.0g/L。按此工艺酿制,发酵时间12d后苹果酒中的乳酸含量由0.99g/L提高到了3.5g/L,苹果酸含量从4g/L下降到0.25g/L,且苹果酸降解发生在菌株Z25的对数生长阶段。显然,辅助肠膜明串珠菌肠膜亚种Z25到苹果酸乳酸发酵中,可以改善苹果酒的品质。     

Potential and limitations of MALDI-TOF MS for discrimination within the species Leuconostoc mesenteroides and Leuconostoc pseudomesenteroides

The discriminatory power of MALDI-TOF MS (matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry) was evaluated for differentiation of bacterial strains within Leuconostoc mesenteroides and Leuconostoc pseudomesenteroides species. Protein fingerprints were generated with MALDI-TOF MS for 24 Leuconostoc strains and analyzed with ClinProTools at species level and below. A treatment of bacterial cells prior to MALDI-TOF MS analysis was optimized applying different lysozyme concentrations. A pre-treatment with a lysozyme concentration of 12.5 μg ml^?1 for 30 min exposure time enhanced the reproducibility of the spectra but did not influence the cluster analysis in ClinProTools. The cluster analysis resulted in the identification of seven different peak patterns shared among twelve strains of L. pseudomesenteroides and eight peak patterns shared among twelve strains of L. mesenteroides. The protein fingerprints of 24 Leuconostoc strains were sufficiently diverse for a reliable discrimination of half of the analyzed starter cultures at strain level. The other half of the strains could only be identified at cluster level. The discrimination at subspecies level was not possible on the basis of MALDI-TOF MS profiling. The MALDI-TOF MS methodology delivered interesting information about the diversity of bacterial isolates belonging to the two species L. mesenteroides and L. pseudomesenteroides but had its limitations for subspecies discrimination of unknown isolates as well as strain identification.     

Leuconostoc mesenteroides producing bifidogenic growth stimulator via whey fermentation

Two whey culture supernatants of CJNU 0147 and CJNU 0400 were found to effectively enhance the growth of Bifidobacterium longum FI10564 by 1.58 fold compared to non-fermented whey medium. The 2 isolates were identified to be Leuconostoc mesenteroides (99% identity) by 16S rRNA gene sequence analysis. To determine whether the whey culture supernatant of CJNU 0147 selectively stimulate the growth of bifidobacteria, the growth rates of Escherichia coli DH5α, Enterococcus faecalis KFRI 675, Listeria monocytogenes ATCC 19111, and Staphylococcus aureus ATCC 14458 with the supernatant were measured. In these experiments, the supernatant slightly inhibited the growths of bacteria except for E. coli, indicating that the whey culture supernatant had very little influence on the growth of these bacterial strains.     

Tracking of deliberately inoculated Leuconostoc mesenteroides and Lactobacillus brevis in kimchi

Food Science and Biotechnology - The objective of this study was to track intentionally inoculated Leuconostoc mesenteroides (11251) and Lactobacillus brevis (B151) strains in kimchi using random...     

辣椒酱发酵菌肠膜明串珠菌C27高密度培养条件优化

为了实现辣椒酱发酵肠膜明串珠菌（Leuconostoc mesenteroides）C27的高密度培养,以MRS肉汤培养基为基础,L. mesenteroides C27的菌体密度为评价指标,采用单因素试验和响应面法对培养基中的碳源、氮源、生长因子进行优化,同时采用响应面法对培养条件进行优化。结果表明,最佳培养基配方为蔗糖21 g/L,酵母浸粉22 g/L,土豆汁14 g/L;最佳培养条件为发酵温度38.4 ℃、初始pH值6.2,接种量2.4%。在此优化条件下培养24 h,L. mesenteroides C27的菌体密度（OD600 nm值）达1.034,活菌数为1.30×109 CFU/mL。     

Modelling the growth of Leuconostoc mesenteroides by Artificial Neural Networks

The combined effect of temperature (10.5 to 24.5 degrees C), pH level (5.5 to 7.5), sodium chloride level (0.25% to 6.25%) and sodium nitrite level (0 to 200 ppm) on the predicted specific growth rate (Gr), lag-time (Lag) and maximum population density (yEnd) of Leuconostoc mesenteroides under aerobic and anaerobic conditions, was studied using an Artificial Neural Network-based model (ANN) in comparison with Response Surface Methodology (RS). For both aerobic and anaerobic conditions, two types of ANN model were elaborated, unidimensional for each of the growth parameters, and multidimensional in which the three parameters Gr, Lag, and yEnd are combined. Although in general no significant statistical differences were observed between both types of model, we opted for the unidimensional model, because it obtained the lowest mean value for the standard error of prediction for generalisation. The ANN models developed provided reliable estimates for the three kinetic parameters studied; the SEP values in aerobic conditions ranged from between 2.82% for Gr, 6.05% for Lag and 10% for yEnd, a higher degree accuracy than those of the RS model (Gr: 9.54%; Lag: 8.89%; yEnd: 10.27%). Similar results were observed for anaerobic conditions. During external validation, a higher degree of accuracy (Af) and bias (Bf) were observed for the ANN model compared with the RS model. ANN predictive growth models are a valuable tool, enabling swift determination of L. mesenteroides growth parameters.     

Contribution of Lactobacillus plantarum and Leuconostoc mesenteroides subsp. mesenteroides to Atypical Odors of Beef Strip Loins

Sterile beef strip loin tissue was inoculated with Lactobacillus plantarum or Leuconostoc mesenteroides subsp. mesenteroides, placed in sterile sample bottles which were purged with CO₂, and stored up to 28 days at 3°C. Volatile compounds detected in the headspace of these samples included acetone, toluene, acetic acid, ethyl acetate, a C₇ hydrocarbon, and trichloromethane. The profile of volatiles in packaged sterile loin tissue stored for up to 28 days was similar. However, the inoculated samples spoiled (soured) at a faster rate.     

Modeling of growth and bacteriocin production by Leuconostoc mesenteroides E131

Leuconostoc mesenteroides E131, isolated from dry fermented sausages, produces an antimicrobial agent, characterized as bacteriocin. The effect of pH and temperature on growth and bacteriocin production, using MRS broth as growth medium, was studied in a fermentor. The pH value at which the best cell growth was observed (6.5) did not coincided with the value at which the maximum bacteriocin activity was attained (5.5). In contrast, the maximum bacteriocin activity was attained at temperature (25 °C) close to the optimum temperature for cell growth (25–30 °C). Notably, the range of pH and temperature for good bacteriocin production was within the range used for sausage fermentation. An empirical model was developed to describe the growth and bacteriocin production in different pH and temperature conditions. The model was able to describe growth and bacteriocin production and it could be used to predict the kinetic parameters of growth and bacteriocin production within the pH and temperature range examined.     

假肠膜明串珠菌产细菌素复配抑菌液的筛选及保鲜效果研究

目的 筛选出最优的假肠膜明串珠菌（Leuconostoc mesenteroides, LM）产细菌素复配抑菌液,同时探究抑菌液对冷鲜鸡肉的保鲜效果。方法 以冷鲜鸡肉及其主要腐败菌为研究对象,研究假肠膜明串珠菌产细菌素的最佳生长周期,并利用假肠膜明串珠菌产细菌素抑菌液、乳酸链球菌素抑菌液、假肠膜明串珠菌产细菌素和柚子精油复配抑菌抑菌液以及假肠膜明串珠菌产细菌素和茶多酚复配抑菌液分别浸泡鸡肉,从肉的pH、汁液流失率、色度、菌落总数、挥发性盐基氮（total volatile basic nitrogen, TVB-N）、感官评定等评价其对鸡肉冷藏品质的影响,比较以上几种抑菌液对鸡肉的保鲜效果,筛选出最佳的抑菌液。结果 假肠膜明串珠菌产细菌素的生长周期与其抑菌活性呈一定正相关。实验组的4种抑菌液均能延缓冷鲜鸡肉劣变,但1.5%假肠膜明串珠菌产细菌素抑菌液、40 mg/L乳酸链球菌素抑菌液对冷鲜鸡肉保鲜效果有限。而1.5%假肠膜明串珠菌产细菌素和0.2%茶多酚复配抑菌液、1.5%假肠膜明串珠菌产细菌素和10%柚子精油复配抑菌液的保鲜效果较好,尤其在以1.5%假肠膜明串珠菌产细菌素和10%柚子精油复配抑菌液液处理时,对冷鲜鸡肉的保鲜作用最强。结论 1.5%假肠膜明串珠菌产细菌素和10%柚子精油复配抑菌液对冷鲜鸡肉具有最佳的保鲜效果。     

The linamarase of Leuconostoc mesenteroides: Production,isolation and some properties

Leuconostoc mesenteroides was found to produce highly active linamarase when linamarin was incorporated in its growth medium. The enzyme was isolated from the bacterium and partially purified using diethylaminoethyl (DEAE) cellulose. Its activity was measured spectrophotometrically using linamarin extract. This yielded 62.2 mg CN^? g^?1 of linamarin. A study of some of its properties showed it was active in the temperature range of -10 to +45°C, with an optimum at 29°2°C. Activity was observed over a wide pH range, 4.0–8.0, with optimum at 6.0–6.5. Its pH of stability was 5.5–7.5, while above pH 8.0 there was a rapid loss of activity. Incubating the enzyme at 50°C led to loss of over 90% of its activity within 18 min. The optimal substrate concentration was 0.15–0.20 ml^?1. Whereas above 0.25 mg ml^?1 there was no observable increase in activity, loss of activity became more pronounced below 0.10 mg ml^?1 of substrate.     

Cloning of levansucrase from Leuconostoc mesenteroides and its expression in Pichia pastoris

A gene (m1ft) encoding levansucrase from Leuconostoc mesenteroides has been previously cloned in Escherichia coli. Presently, m1ft was cloned and secretively expressed in Pichia pastoris. Methanol induction of recombinant M1FT resulted in the production of active levansucrase (PM1FT). PM1FT-5 was expressed as an active form, but the protein accumulated mainly inside the cells, representing about 5% of total cell proteins. M1FT was secreted into the culture supernatant with a maximum yield of 14,400 U/L using fed-batch fermentations. P. pastoris-derived M1FT displayed catalytic activities comparable to those of the E. coli-derived M1FT. PM1FT was glycosylated at its 2 potential N-glycosylation sites.     

Purification and characterization of a bacteriocin produced by Leuconostoc mesenteroides E131

Leuconostoc mesenteroides E131, isolated from Greek traditional fermented sausage, prepared without the addition of starters, produces a bacteriocin which is active against the pathogen Listeria monocytogenes. The bacteriocin was purified by 50% ammonium sulphate precipitation, cation exchange, and reverse-phase chromatography. Bacteriocin is active at pH values between 4.0 and 9.0 and retains activity after incubation for 1 h at 100 °C. Proteolytic enzymes inactivated the bacteriocin after 1 h of incubation, while renin resulted in full inactivation only after 24 h. Lipase resulted in full inactivation after 4 h. Applying molecular methods, it was determined that the bacteriocin produced, named as mesenterocin E131, was identical to mesenterocin Y105 and was expressed during the exponential growth phase.     

Isolation and antioxidative activity of amino acid derivatives produced by Leuconostoc mesenteroides

Food Science and Biotechnology - One new phenyl lactic acid derivative, N-(5-amino-2-hydroxy-1-oxopentyl)-tyrosine (2), and three known metabolites [(S)-8-hydroxy-4-hydroxy-phenylpropanoic acid...     

保藏方法和期限对肠膜明串珠菌发酵收率的影响

通过对肠膜明串珠菌菌种进行冷冻管、液体管和斜面试管等保藏方法的比较,结果表明:冻干菌种保藏方法最优,保存期可达24年以上;但必须先优化菌种,选择发酵收率高和稳定性好的菌株制备冻干菌种,以供工业生产所需.     

Evaluation of exopolysaccharide production by Leuconostoc mesenteroides strains isolated from wine

ABSTRACT:  Exopolysaccharide (EPS)-producing lactic acid bacteria are responsible for the alteration of wine and other fermented beverages. The potential to produce EPS was investigated for Leuconostoc mesenteroides strains isolated from Spanish grape must and wine. Most strains were able to produce EPS from sucrose containing media. Based on their EPS-producing phenotype and on their EPS monosaccharide composition, the L. mesenteroides strains analyzed could be arranged in 2 groups. One group comprises mucoid strains producing a glucan polymer, and the other group includes strains producing a fructan polymer. The presence of a glucosyltransferase encoding gene in the glucan producing L. mesenteroides strains was assayed by PCR. Two primer sets, PF1-PF8 and GTFF-GTFR, were used to amplify internal fragment of known glucosyltransferase genes. None of the glucan-producing strains gave a positive amplicon by the primer sets used. Therefore, new tools need to be developed to broaden the range of potentially spoiling agents detected by PCR in fermented beverages.