乳酸菌处理虾壳发酵液总酸度的测定方法研究

采用常规滴定法和电位滴定法测定乳酸菌处理虾壳发酵液的总酸度,并通过F检验法和t检验法判断两种方法精密度和准确度之间是否存在显著性差异。结果表明,发酵液稀释20倍可以降低溶液颜色对实验结果的影响,提高测试结果的准确度。微型常规滴定法可以取得与常量滴定法一样的结果,但对实验人员的实验技能要求较高。电位滴定法和微型常规滴定法的精密度和准确度均不存在显著性差异,均适合于测定产乳酸、蛋白酶菌发酵脱除虾壳钙盐和蛋白质制得甲壳素发酵液的总酸度。     

Production of high‐quality chitin and chitosan from preconditioned shrimp shells

Chitin and chitosan with improved characteristics were produced from shrimp shell waste preconditioned by limited decay or by treatment with 0.016 mol L^?1 benzoic acid. Preconditioned shrimp shells were transparent, had a clean surface and were susceptible to demineralization and deproteinization using 0.68 mol L^?1 HCl and 0.62 mol L^?1 NaOH, respectively. The ash and protein residues in the final chitosan were about 0.2% and 0.4%, respectively, the viscosity was up to 7000 cps, and the solubility and transparency nearly 100%. In comparison with treatment at ambient temperature (30 °C) without preconditioning, the chemical consumption, the duration of the treatment, ash and protein residues was reduced to 75–25%, whereas viscosity and absence of insolubles improved by a factor of 2–3. Copyright © 2006 Society of Chemical Industry     

pH值对电渗析法回收厨房垃圾发酵液中乳酸的影响

随着人们环保意识的加强,乳酸作为生物可降解塑料的原料日益受到重视．目前,国内外一些专家都在积极开发廉价乳酸的分离新工艺,如萃取、电渗析、反渗透．电渗析法作为一种新的膜分离技术过去主要运用在苦咸水及海水的淡化上,现在欧美、日本等一些发达国家已运用电渗析法来分离、浓缩回收化工产品．     

Recovery and concentration by electrodialysis of tartaric acid from fruit juice industries waste waters

Electrodialysis (ED) has been used as a membrane technique to concentrate tartaric acid from ion exchange regeneration waters obtained in grape juice treatment. The initial ion tartrate concentration in these streams varies between 1 and 10 kg m⁻³ and can be concentrated more than 60% (53·2 kg m⁻³ after 13300 s). Permeate flux of other common ionic components has been shown. Optimum intensities and current efficiency have been calculated with synthetic solutions. A mathematical approach has been used to predict final tartaric acid concentration and electro-osmotic effects. ©1997 SCI     

Production of L‐lactic acid with very high gravity distillery wastewater from ethanol fermentation by a newly isolated Enterococcus hawaiiensis

BACKGROUND: A great amount of wastewater with high contents of chemical oxygen demand (COD) are produced by ethanol production. It would be useful to utilize distillery wastewater to produce L‐lactic acid, which could be a high additional value byproduct of ethanol production. The fermentation process of L‐lactic acid production by a newly isolated Enterococcus hawaiiensis CICIM‐CU B0114 is reported for the first time. RESULTS: The strain produced 56 g L^?1 of L‐lactic acid after cultivation for 48 h in optimized medium consisting of (g L^?1) 80 glucose, 10 peptone, 10 yeast extract, 1.5 Na₂HPO₄ and 0.2 MgSO₄. E. hawaiiensis CICIM‐CU B0114 was isolated and purified by subculture for growing and producing L‐lactic acid in distillery wastewater of very high gravity (VHG) from ethanol fermentation. L‐lactic acid fermentation was further studied with distillery wastewater substrate in 7 L and 15 L fermentors. The results showed that L‐lactic acid concentrations of 52 g L^?1 and 68 g L^?1 was achieved in 7 L and 15 L fermentors with the initial sugar concentrations of 67 g L^?1 and 87 g L^?1, respectively. CONCLUSION: The production of L‐lactic acid by the newly isolated E. hawaiiensis CICIM‐CU B0114 was carried out and the fermentation medium was optimized by orthogonal experimental design. This new strain holds the promise of L‐lactic acid production utilizing distillery wastewater from VHG ethanol fermentation. Copyright © 2010 Society of Chemical Industry