Abstract: A micro reactor includes a filter 2 having a plurality of fine pores; a plurality of compartments 3a and 3b formed by the filter; and an element which enables a material passing through the fine pores to be transferred between the compartments, wherein the element which enables the material to be transferred between the compartments 3a and 3b can change surface tension of the material. In addition, volume of the material contained in the compartments 3a and 3b may change. In addition, the change in the surface tension of the material is carried out by selectively irradiating or not-irradiating light onto the surface thereof by using the filter 2 having a titan oxide surface. In addition, the change in the volume of the material contained in the compartments 3a and 3b is carried out by using light, heat, electricity, or magnetism.

Abstract: A recombinant DNA replicable and expressible in Escherichia coli is disclosed which encodes glucose dehydrogenase originating from Bacillus megaterium. A DNA sequence encoding the glucose dehydrogenase is incorporated into an E. coli vector and then used to transform an E. coli host. Also disclosed are transformants and recombinant DNA incorporating thermostable glucose dehydrogenase, wherein at least one amino acid in glucose dehydrogenase at positions 96, 252, and 253 is replaced by a thermostability-conferring amino acid.

Abstract: A novel gene coding for thermostable .beta.-galactosidase, novel recombinant DNA in which a DNA fragment containing the above gene is inserted, novel Bacillus subtilis in which the above recombinant DNA is introduced, and novel thermostable .beta.-galactosidase obtained by cultivating the above Bacillus subtilis.