During the production of ε-poly-L-lysine (ε-PL) in fed-batch fermentation, the decline of ε-PL synthesis often occurs at middle or late phase of the fermentation. To solve the problem, we adopted two strategies, namely pH shift and feeding yeast extract, to improve the productivity of ε-PL. ε-PL productivity in fermentation by pH shift and feeding yeast extract achieved 4.62 g/(L x d) and 5.16 g/(L x d), which were increased by 27.3% and 42.2% compared with the control ε-PL fed-batch fermentation, respectively. Meanwhile, ε-PL production enhanced 36.95 g/L and 41.32 g/L in 192 h with these two strategies, increased by 27.4% and 42.48% compared to the control, respectively. ε-PL production could be improved at middle or late phase of fed-batch fermentation by pH shift or feeding yeast extract.
Batch Cell Culture Techniques ; Fermentation ; Industrial Microbiology ; Nitrogen ; chemistry ; Polylysine ; biosynthesis

Objective: To investigate the effect of 1,3-diacylglycerol(DAG) on reducing blood lipid and obesity. Methods: Fifty SD rats were divided into five groups: triacylglycerol (TAG) low-fat diet, TAG high-fat diet, DAG high-dose , medium-dose and low-dose diet. The rats were fed for 6 w, and body weight was recorded every week. At the end of the experiment, the ratio of visceral fat to body weight was calculated, and blood lipid was analyzed. Results: The body weight of rats in TAG high-fat group was significantly higher than that in TAG low-fat group from the 2nd week (P

The energy consumption in a Chinese ethanol manufacturer with cassava as the feedstock, has been reduced to a zero-closed level. If the R & D on technical integration of high ethanol concentration fermentation, methane fermentation technique, steam and electricity co-generation system, new distillation technology, and the wastewater reutilization, is carried out continuously, the proposed "zero energy consumption and wastewater" technique could be realized in fuel ethanol production process.
Bioelectric Energy Sources ; Ethanol ; metabolism ; Fermentation ; Manihot ; metabolism ; Methane ; metabolism ; Waste Disposal, Fluid ; methods

A bacterium D 97 whose enducellular enzymes can produce trehalose from starch or maltooligosaccharides was isolated from Datian in Northeast of China The morphological, Cultural and Physiological Characteristics of trehalose prodicing bacterium D 97 were described in this paper There are galactose and lysine in its cell wall but no diaminopimelic acid (DAP) arabinose The content of G+C mol% is 61 3 The full lenth of 16s rDNA (770bp) has been tested and compared with the type strains of all known Arthrobacter sp in Genebank, the results showed the similarity values of 16s rDNA sequence between bacterium D 97 and Arthrobacter nicotinovorus were 97 98%, therefore bacterium D 97 was nameed Arthrobacter nicotinovorus D 97 In this paper we also carried out some comparisons of Physiological Characteristics between Arthrobacter nicotinovorus D 97 and Arthrobacter sp Q36