Disclosed is a method for increasing expression level of recombinant proteins in Bacillus subtilis through co-expressing Bacillus-derived enhancer factor, belonging to the technical field of enzyme engineering. According to the present disclosure, genes encoding recombinant proteins are respectively co-expressed with Bacillus-derived PonA, PonA truncated forms, OppA or SppA, so as to improve the expression level of the recombinant proteins. The results show that the method provided by the present disclosure can increase the expression level of ultra-high temperature amylase, medium temperature amylase or sucrose isomerase at the shake flask level to 3.96 times, 1.49 times and 2.26 times. The expression level of ultra-high temperature amylase can be increased by 26% in high-density fermentation of a 3L bioreactor. The B. subtilis provides a new developable target as an recombinant protein expression host, and provides technical support for the optimization and modification of the enhancer factors.

The present invention is directed towards genetic modification of native gene encoding for sucrose isomerase and isomaltulose synthase to substantially increase the expression level of these enzymes and use of said enzymes in a process to produce rare disaccharides such as isomaltulose and trehalulose. Also disclosed in the present invention is expression constructs comprising the modified genes and a host cells to express the same.

The present invention is directed towards genetic modification of native gene encoding for sucrose isomerase and isomaltulose synthase to substantially increase the expression level of these enzymes and use of said enzymes in a process to produce rare disaccharides such as isomaltulose and trehalulose. Also disclosed in the present invention is expression constructs comprising the modified genes and a host cells to express the same.

The invention provides granules comprising A) at least one enzyme selected from at least one of the groups selected from transferases of EC 2, hydrolases of EC 3, lyases of EC 4 and isomerases of EC 5, B) at least one polymer selected from C.sub.1-C.sub.10-alkyl acrylate polymer, C.sub.1-C.sub.10-alkyl methacrylate polymer and C.sub.1-C.sub.10-alkyl acrylate-C.sub.1-C.sub.10-alkyl methacrylate copolymer, preferably C.sub.1-C.sub.10-alkyl acrylate-C.sub.1-C.sub.10-alkyl methacrylate copolymer and C) at least one inorganic carrier material.