共查询到17条相似文献,搜索用时 46 毫秒
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豆腐酸浆中高产蛋白的白地霉发酵条件的研究 总被引:3,自引:0,他引:3
本文对从酸浆中分离筛选出的白地霉FL44菌株在以黄浆水为主的培养基的条件下生产单细胞蛋白的发酵条件进行了初步研究,并对其发酵过程作了动态分析。结果表明:培养基组成、初始pH值、摇瓶装量与培养时间等,均对该菌株细胞生物量和蛋白产量有影响,优化培养基组成为:废糖蜜5%、(NH4)2HPO4 1%);培养条件为:培养基初始PH5.5,装量40mL/250mL,摇瓶,摇瓶转速为220rpm,30℃培养48h;菌体生物量及蛋白产量分别为:15.2g/L和7.42g/L。 相似文献
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探讨了白地霉发酵过程中菌体量的检测方法,对白地霉的细胞组分麦角固醇和氨基葡萄糖,能否作为菌体量检测指标的可行性进行了比较分析。结果表明:氨基葡萄糖在白地霉细胞中的含量较为稳定,在不同的培养时间、培养条件和培养基中都有较好的稳定性,可以作为白地霉菌体量的检测指标;麦角固醇受培养时间和培养基成分的影响较大,含量不稳定,不太适合作为白地霉菌体量的检测指标。用氨基葡萄糖法测得的白地霉生长曲线与用干重法测得的生长曲线变化一致,能够较为准确地反映白地霉菌体量变化。将此方法应用到白地霉固态发酵中,可快速得到白地霉固态发酵过程中的菌体量变化,为以后固态发酵菌体量的测定提供了依据。 相似文献
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Majda Aziza Lydia Adour Abdeltif Amrane 《Journal of the science of food and agriculture》2008,88(6):984-988
BACKGROUND: Metabolisation of carbon and nitrogen substrates is a key factor during the ripening process of white soft cheeses but has not previously been examined in terms of energy substrate efficiency. Such work could be useful to improve physiological knowledge concerning Geotrichum candidum, a yeast involved in the neutralisation of curd during ripening. Its behaviour was therefore examined during batch cultures on simple (glutamate) or complex (peptones) substrates as nitrogen and carbon sources and lactate as a second carbon source. RESULTS: In addition to their assimilation as carbon and nitrogen sources, G. candidum used peptides and amino acids as energy sources during growth in preference to lactate. Contrarily, during stationary state, lactate was preferred over peptides and amino acids for carbon dissimilation for energy supply, allowing the avoidance of ammonium production. Indeed, lactate dissimilation theoretically yields 15 adenosine triphosphates (ATPs), while only nine ATPs are theoretically yielded during the dissimilation of an amino acid such as glutamate. CONCLUSION: This behaviour can be considered as an energy‐saving response. Indeed, the use of peptides and amino acids as energy sources in addition to being used as carbon and nitrogen sources during G. candidum growth can be related to its deaminating activity and was in agreement with the better energy efficiency expected from utilisation of the same substrate as both carbon and energy source. Contrarily, the better efficiency of lactate dissimilation led to its use during stationary state instead of peptides and amino acids. Copyright © 2008 Society of Chemical Industry 相似文献
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对从酱香大曲中分离的白地霉菌株Geotrichum candidum MTBD进行了鉴定,并对该菌株的固态发酵和液态条件下产蛋白酶及其产酶条件进行了研究,以及该菌株利用酿酒原料的固态和液态发酵产物分析。结果表明,该菌株能产较高活力的蛋白酶,发酵代谢产物包括酸类、酯类、芳香族化合物、醛酮类、含氮化合物等多种成分,与茅台地区酱香型白酒的风味成分分析结果进行比较分析,结果表明,该菌株也是酱香型白酒生产的主要功能菌株,对提供发酵动力和风味形成具有重要的贡献。 相似文献
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The fungus Geotrichum candidum 4013 produces two types of lipases (extracellular and cell‐bound). Both enzymes were tested for their hydrolytic ability to p‐nitrophenyl esters and compounds having a structure similar to the original substrate (triacylglycerols). Higher lipolytic activity of extracellular lipase was observed when triacylglycerols of medium‐ (C12) and long‐ (C18) chain fatty acids were used as substrates. Cell‐bound lipase preferentially hydrolysed trimyristate (C14). The differences in the abilities of these two enzymes to hydrolyse p‐nitrophenyl esters were observed as well. The order of extracellular lipase hydrolysis relation velocity was as follows: p‐nitrophenyl decanoate > p‐nitrophenyl caprylate > p‐nitrophenyl laurate > p‐nitrophenyl palmitate > p‐nitrophenyl stearate. The cell‐bound lipase indicates preference for p‐nitrophenyl palmitate. The most striking differences in the ratios between the activity of both lipases (extracellular : cell‐bound) towards different fatty acid methyl esters were 2.2 towards methyl hexanoate and 0.46 towards methyl stearate (C18). The Michaelis constant (Km) and maximum reaction rate (Vmax) for p‐nitrophenyl palmitate hydrolysis of cell‐bound lipase were significantly higher (Km 2.462 mM and Vmax 0.210 U/g/min) than those of extracellular lipase (Km 0.406 mM and Vmax 0.006 U/g/min). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Enzymatic and molecular characteristics of Geotrichum candidum strains as a starter culture for malting 下载免费PDF全文
Michał Piegza Danuta Witkowska Regina Stempniewicz 《Journal of the Institute of Brewing》2014,120(4):341-346
Geotrichum candidum yeasts are proposed as a starter culture during malting. They have a double positive effect on the process. They eliminate the fungal pathogenic microflora and improve the technological properties of the finished product, malt. Among published research little or no information can be found considering the biosynthesis of hydrolytic enzymes. Most of the data is related to the production of lipases, proteases and cellulases. This paper examines the enzymology of a number of G. candidum strains. The main focus within the evaluation process was placed on whole cell barley grain cultivation. Hydrolase, which is present in cell wall degradation, was found at a satisfactory level. All tested strains produced both β‐1,3‐glucanases and β‐1,4‐glucanases capable of hydrolysing barley β‐glucan and reducing the amount of this polysaccharide in the wort. Molecular analysis of the tested strains with the use of restriction fragment length polymorphism–polymerase chain reaction and randomly amplified polymorphic DNA confirmed not only the species affiliation, but also the genetic similarity between the tested strains. Copyright © 2014 The Institute of Brewing & Distilling 相似文献
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在小麦淀粉废水中培养白地霉的研究 总被引:5,自引:0,他引:5
将白地霉分别培养在液化及液化后再糖化的小麦淀粉废水中,对培养过程中的降糖,生物量,蛋白酶和糖化酶活力,所态氮,pH值的变化进行了研究。结果表明:在液化后再糖化的小麦淀粉废水中,白地霉能良好生长,生物量得率高。同时对白地霉在糖化淀粉废水中生长的动力学进行了初步研究。 相似文献