Abstract: The present disclosure discloses a Bacillus licheniformis cell stably and repeatedly used for the conversion and synthesis of D-psicose, and belongs to the field of biotechnology. D-psicose is a functional sugar with high health value and has broad application prospects in food, medicine, health care and other fields. The B. licheniformis cell of the present disclosure efficiently expresses recombinant D-psicose-3-epimerase, and can convert high-concentration fructose as a substrate into D-psicose. After the whole-cell catalyst is reused 10 times, the conversion rate is not less than 30%. Compared with pure enzyme or single-use whole-cell conversion methods, this technology for the synthesis of D-psicose has significant advantages such as low catalyst cost and simple separation and purification.

Abstract: Disclosed is an Aspergillus niger seed continuous culture method, comprising the steps of: (1) at a startup stage, Aspergillus niger spores are inoculated into a seed culture medium to obtain a seed liquid; (2) at a seed continuous culture stage, continuous dispersion treatment is performed on the seed liquid obtained in step (1), continuous culture is performed on the seed liquid obtained by dispersion, and meanwhile, a fresh seed feed medium is replenished; and (3) at a stop stage, the replenishment of the fresh seed feed medium and the dispersion treatment are stopped, continuous culture is performed to obtain a seed liquid, and then the seed liquid is transferred into the fermentation medium for fermentation culture. The method according to the present invention makes breakthrough to solve problems that multi-cellular filamentous bacteria grow slowly and mycelium pellets are easy to lose in continuous culture, thus fully achieving seed continuous culture.

Abstract: Disclosed is an Aspergillus niger seed continuous culture method, comprising the steps of: (1) at a startup stage, Aspergillus niger spores are inoculated into a seed culture medium to obtain a seed liquid; (2) at a seed continuous culture stage, continuous dispersion treatment is performed on the seed liquid obtained in step (1), continuous culture is performed on the seed liquid obtained by dispersion, and meanwhile, a fresh seed feed medium is replenished; and (3) at a stop stage, the replenishment of the fresh seed feed medium and the dispersion treatment are stopped, continuous culture is performed to obtain a seed liquid, and then the seed liquid is transferred into the fermentation medium for fermentation culture. The method according to the present invention makes breakthrough to solve problems that multi-cellular filamentous bacteria grow slowly and mycelium pellets are easy to lose in continuous culture, thus fully achieving seed continuous culture.