Abstract: According to the reported amino acid sequence of single-chain monellin, the codon bias of Pichia pastoris and Morus alba L., a synthetic monellin gene was achieved. Then, the enhanced green fluorescent protein (EGFP) gene was added into the downstream of monellin gene to construct an expression vector named as pPIC9K-M-E. Based on transformation of yeast by electroporation, the expression vector pPIC9K-M-E was successfully imported into Pichia pastoris. PCR amplification, fluorescence detection, Western Blot analysis and SDS-PAGE results demonstrated that the fusion protein was expressed and the fusion protein revealed high intensity of sweetness, which was almost 500 times sweeter than the sucrose with same amount.

Key words: monellin sweet protein, EGFP, eukaryotic expression, mulberry