To enhance the production of ε-poly-L-lysine (ε-PL) by improving dissolved oxygen level of the fermentation system, different oxygen-vectors were added to broth and n-dodecane was screened as the best oxygen-vector. The best amount of n-dodecane was 0.5% (V/V) and the best time was at start of the fermentation. In a fed-batch fermentation in a 5 L bioreactor, ε-PL concentration reached a maximum of (30.8 ± 0.46) g/L and the dry cell weight obtained was (33.8 ± 0.29) g/L, increasing by 31.6% and 20.7% compared with the control group, respectively. This improvement can be related to 0.5% n-dodecane could maintain dissolved oxygen concentration > 32% of air concentration compared with 23.8% in ε-PL production phase, and the production of a main by-product, poly-L-diaminopropionic acid, fell by 31%. These results indicated that the dissolved oxygen level in the broth was improved by adding n-dodecane, which can inhibit the by-product production and improve the biosynthesis of ε-PL.
Alkanes ; chemistry ; Batch Cell Culture Techniques ; Bioreactors ; Fermentation ; Oxygen ; chemistry ; Polylysine ; biosynthesis

PURPOSE: Ginseng is a traditional Asian remedy for sexual dysfunction. The purposes of this study were to investigate the effects of Korean red ginseng (KRG) on the vaginal blood flow and tissue structure in female castrated rats. MATERIALS AND METHODS: Female Spague-Dawley rats (200-210gm) were divided into 4 groups: the control (n=20), castration (n=30), and castration plus oral administration of KRG extracts (50 and 100mg/kg/day, n=15 and n=15, respectively). After 1 month of treatment, the serum estrogen and total cholesterol levels were measured. The vaginal blood flow was measured using laser Doppler flowmeter before and after pelvic nerve stimulation (PNS). The vaginal tissue was processed for Masson's trichrome stain, immunohistochemistry and Western blotting. RESULTS: The serum estrogen level was significantly decreased in the castration group (0.8+/-1.9ng/ml); however, it increased up to the control level (2.2+/-1.3ng/ml) in both the KRG administration groups (p<0.05). The PNS-induced vaginal blood flow tended to improve in the KRG treatment groups. On the histology, the vaginal epithelial layer and submucosal microvasculature showed improvement in the KRG treatment groups. The expression of estrogen receptor increased in the KRG treatment groups compared to the castration group. CONCLUSIONS: These results suggested that KRG extracts seem to have an estrogenic effect on castrated female rats. This implies that the KRG extracts may have an ameliorating effect on sexual function in menopausal woman.
Administration, Oral ; Animals ; Asian Continental Ancestry Group ; Blotting, Western ; Castration ; Cholesterol ; Estrogens ; Female* ; Flowmeters ; Humans ; Immunohistochemistry ; Menopause ; Microvessels ; Panax* ; Rats* ; Vagina