Poster 3-26

Chen Hongzhang and Li Zuohu

Laboratory of Biochemical Engineering
Institute of Chemical Metallurgy
Chinese Academy of Sciences
Beijing, China 100080

Telephone: +86-10-8262-7067; Fax: +86-10-6256-1822; E-mail: chenhzh@yahoo.com

Large-scale solid-state fermentation is an important area of research. A new method of operation and a new solid-state fermenter are described in this paper. The pressure of the fermenter varied between the peak and the low-pressure range. The variable period, 15–150 min, consisted of compressed air time, steady time for peak pressure, purge air time, and time for steady low pressure; however, the inside of the fermenter was always at a positive pressure. The compressed air time was 1–5 min, but the purge air time was only <1 min. The peak and the low pressures were 1.5–3.5 kg/cm² and 0.1–0.5 kg/cm², respectively.

Pulsating pressure operation was steady state for solid media but dynamic for the gas phase. There were many advantages for the pressure pulsation of solid materials. (1) Gas molecules are pervasive and tend to make pressure pulsation act on a single-particle scale. (2) The swelling of media takes place during the process of purge pressure, thus aiding the growth of microorganisms. (3) The fermenter discussed here is a simple structure and uses a lower level of energy than the usual type of vessel. Pressure pulsation is a normal action and is beneficial to mass, heat, and information transfer of the cell membrane. The results of its evaluation for cellulase indicated that a twofold to threefold increase in production can be obtained in a large-scale fermenter of 25- to 75-m³ capacity.