Microbial engineering for easy downstream processing.

Downstream is a very expensive process for microbial fermentation. It usually involves complicated equipment and processes to obtain desired chemicals or materials from intra- or/and extracellular spaces of microorganisms. Recently, it becomes possible to simplify the microbial cell separation processes by morphologically engineering the shapes of small microorganisms. Cells can be induced aggregated, or enlarged into fibers or large spheres, so that gravity sedimentation or press filtration becomes a convenient operation. Various genes related to the microbial morphology have been manipulated to obtain large shapes and multiple fission to form long fibers or large spheres. At the same time, induced lysis of cells can be achieved by introducing lysis gene into the cells. To achieve better economy, it is desirable to receive products both in broths and in cell masses. Co-production of different chemicals produced intracellularly and extracellularly could be an effectively economical way. Based on these novel methods, easy cell separation in the downstream processing is expected to be achieved soon.