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baculus siwtms can ettecmeły De used m many cases. For examples, it can increase body weight gaili of chicken and turkeys (Jiraphocakul, 1990, Samanya,2002). Tliis bacteria forms spores which can survive better tlian vegetative celi in harsh environnient. Tliis makes the commercial distribution morę feasible tlian non-spore forming bacteria, such as lactic acid bacteria. The Bacillus strain used in tliis study lias been tested by us in chicken farm and proved to be beneficial to egg production. The objective of tliis study is to find a suitable media fomiulation and process for pilot scalę production. Low cost materials froni agriculture, such as molasses and defatted soy bean meal were considered. The proper modę of operation were also considered here. Normally, a fed batch modę can be applied to avoid catabolite repression (Yamane, 1984). Too high sugar content can impede spore formation (Kang, 1992).

oest romniia was seiecteci to use in z l bioreactor culture with 1.5 L culture volume. Dissolved oxygen was keep morę tlian 50 % air saturation. Batch operation was conipared to fed batch operation. In fed batch modę, molasses was added in such a way that reducing sugar was kept in 2-4 g/L rangę. In 75 1. fermenter, operation was in fed batch modę, start i ng volume of 50 L. In tliis case, no molasses was added after the stationary phase of celi growtli was reached. Ali experiments were at 37 C and pl 1 7.

Results and Discussion :

Media considerations.

It was found that molasses based media give good result on celi and spore concentradon in sliake tlask culture (data not shown). However, tliis kind of media can cause a lot of