Fig. 2
From: Bioconversion of vitamin D3 into calcitriol by Actinomyces hyovaginalis isolate CCASU- A11-2
Comparison of bacterial growth and vitamin D3 bioconversion activity of the parent Actinomyces hyovaginalis isolate A11-2 in a shake flask and a laboratory fermenter (Run 1), using the same bioconversion medium. Vitamin D3 bioconversion activity was expressed in terms of amounts of calcitriol produced. In both cases, vitamin D3 (substrate) was added two days after the beginning of the main culture, and the incubation was continued for a further four days. Despite the difference between the mixing manner in the shake flask (Shaking) and that in the laboratory fermenter (Agitation), both were kept at 200 rpm. In addition, aeration was supplied by the headspace above the culture medium in case of the flask while in the fermenter, it was supplied by the introduction of sterile air at 1 vvm. Other applied culture conditions: Inoculum size of 2% v/v; uncontrolled initial pH of 7.8; the temperature of 30 °C (before substrate addition) and of 28 °C (after substrate addition)