TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Protein: (I) has activity at an optimum pH of 6-7, and has a molecular weight of 35 kDa or 75 kDa, as measured by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). (I) is a monomer. (I) is derived from the microbial cells of Penicillium genus microbes. EXAMPLE - Endo-arabinanase was purified from Pencillium chrysogenum 31B (FERM P-19163). The fragment obtained by lysyl proteinase processing of wild-type arabinanase and endo-arabinanase was subjected to sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and the protein fragment was blotted on polyvinyl difluoride (PVDF) film. The spot corresponding to endo-arabinanase was analyzed by protein sequencer. The obtained sequences corresponded to N-terminal and the internal sequence of a fully defined endo-arabinanase sequence of 320 amino acids as given in the specification. cDNA of the endo-arbinanase was cloned by 5' and 3' rapid amplification of cDNA ends (RACE) method. The obtained PCR product was analyzed by sequence analyzer and the cDNA which encodes endo-arabinanase had a fully defined endo-arabinanase base sequence of 963 base pairs as given in the specification. The recombinant protein having endo-arabinanase activity was expressed by inserting the region encoding the protein into suitable vector and expressing the protein by transforming a host with the vector. The transformed host expresses the recombinant protein when cultured in a suitable medium. About 8.05 mg of recombinant protein was recovered from 200 ml of culture solution. The arabinanase activity of the wild-type and recombinant endo-arabinanase was measured. The recombinant protein had 90% or more activity at 0-30 degrees Centigrade. The substrate specificity analysis showed that recombinant protein was highly specific to linear arabinan to which arabinose side chain was not added. The recombinant protein decomposed arabinan contained in agriculture waste materials.