根据GC2MS分析，垃圾渗滤液中有机组分大多是难生物降解的有机化合物，如酚类、杂环类、杂环芳烃、多环芳烃类化合物,约占渗滤液中有机组分的70%以上。本文对渗滤液中典型有机化合物在电化学氧化和厌氧生物组合工艺系统中的降解特性进行了系统研究。结果表明，在电化学处理系统中，杂酚类、酰胺类、苯并噻唑、苯醌、喹啉、萘等有机化合物降解速率高于外222羟基桉树脑和异喹啉等化合物，但前者在厌氧生物处理系统中去除率低；渗滤液原水经过电化学氧化处理后，挥发性脂肪酸（VFA）含量从原水中的0168%增加到电化学出水中的16118%；此组合工艺能够显著降低因渗滤液复杂组分间的增效协同作用和拮抗作用而引起的毒性，系统出水可生化性增强，为进一步研究垃圾渗滤液的处理技术和进行该组合处理系统的大规模开发提供参考。

Pyruvic acid is an important organic acid widely used in the chemical and drug, as well as agrochemical, industries. Compared with the chemical method, biotechnological production of pyruvic acid is an alternative approach because of the low cost. An overview of biotechnological production of pyruvate, including direct fermentative production employing eukaryotic and prokaryotic microorganisms, production by a resting cell method and an enzymatic method as well as the recovery of pyruvate, is discussed. A multi-vitamin auxotrophic yeast strain, Torulopsis glabrata, has been used in the commercial production of pyruvate; emphasis is therefore placed on the mechanism and characteristics of pyruvate production by this strain.

This Mini-Review summarizes the historic developments and technological achievements in the biotechnological production of glutathione in the past 30 years. Glutathione is the most abundant non-protein thiol compound present in living organisms. It is used as a pharmaceutical compound and can be used in food additives and the cosmetic industries. Glutathione can be produced using enzymatic methods in the presence of ATP and its three precursor amino acids (L-glutamic acid, Lcysteine, glycine). Alternatively, glutathione can be produced by direct fermentative methods using sugar as a starting material. In the latter method, Saccharomyces cerevisiae and Candida utilis are currently used to produce glutathione on an industrial scale. At the molecular level, the genes gshA and gshB, which encode the enzymes γ- glutamylcysteine synthetase and glutathione synthetase, respectively, have been cloned from Escherichia coli and over-expressed in E. coli, S. cerevisiae, and Lactococcus lactis. It is anticipated that, with the design and/or discovery of novel producers, the biotechnological production of glutathione will be further improved to expand the application range of this physiologically and medically important tripeptide.

Poly-3-hydroxybutyrate (PHB) is mainly accumulated by Ralstonia eutropha under unbalanced growth conditions, which limits its production in batch or fed-batch modes. The continuous production of PHB was investigated in a two-stage continuous culture system. The first-stage produced cell mass giving the maximal cell dry weight of 27.1g l−1 at 0.21h−1 of dilution rate. High specific cell growth rate results in the decrease of PHB synthesis under glucose-limited and nitrogen-rich conditions in the first-stage. The second-stage produced PHB giving the maximal PHB concentration of 47.6g l−1 at 0.14 h−1 of dilution rate. Specific PHB synthetic rate reached highest value at low dilution rate under nitrogen-limited condition in the second-stage, and decreased with the increase of ammonium concentration in the culture. In the continuous culture system, the maximal PHB productivity could reach 1.43g l−1h−1 at a dilution rate of 0.12h−1, but with relatively low PHB content of 47.6%. Maximal yield of PHB on glucose could reach 0.36g g−1 glucose at 0.075h−1 of dilution rate with relatively high PHB productivity of 1.23g l−1h−1 and PHB content of 72.1%, respectively.

pH is one of the most important environmental factors for cell growth and product formation. Batch microbial transglutaminase (MTG) fermentation by Streptoverticillium mobaraense WSH-Z2 at various pH values ranging from 5.0 to 8.5 was studied. A pH-shift strategy was developed to maximize MTG production in batch MTG fermentation. Based on time courses of the specific cell growth rate and specific MTG formation rate, a two-stage pH-shift strategy in which pH 7.0 was controlled at first 13 h, and then switched to 6.5 after 13 h was developed. By applying this pH-shift strategy in MTG fermentation, the maximal MTG activity and productivity had a significant improvement and reached 3.40u/ml and 81.4u/l/h, respectively, compared to those of constant pH operation (2.90u/ml and 61.4u/l/h).