Production of N -Acetyl- d -Neuraminic Acid by Use of an Efficient Spore Surface Display System

Abstract

ABSTRACT Production of N -acetyl- d -neuraminic acid (Neu5Ac) via biocatalysis is traditionally conducted using isolated enzymes or whole cells. The use of isolated enzymes is restricted by the time-consuming purification process, whereas the application of whole cells is limited by the permeability barrier presented by the microbial cell membrane. In this study, a novel type of biocatalyst, Neu5Ac aldolase presented on the surface of Bacillus subtilis spores, was used for the production of Neu5Ac. Under optimal conditions, Neu5Ac at a high concentration (54.7 g liter −1 ) and a high yield (90.2%) was obtained under a 5-fold excess of pyruvate over N -acetyl- d -mannosamine. The novel biocatalyst system, which is able to express and immobilize the target enzyme simultaneously on the surface of B. subtilis spores, represents a suitable alternative for value-added chemical production.