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Research Project: New Sustainable Processing Technologies to Produce Healthy, Value-Added Foods from Specialty Crops

Location: Healthy Processed Foods Research

Title: Preparation of umami octopeptide with recombined Escherichia coli: feasibility and challenges

Author
item Zhao, Liming - Chengdu University
item Zhang, Yin - Chengdu University
item Venkitasamy, Chandrasekar - University Of California, Davis
item Pan, Zhongli
item Zhang, Longyi - Chengdu University
item Guo, Siya - Chengdu University
item Xiong, Wei - Chengdu University
item Xia, Hu - Chengdu University
item Liu, Wenlong - Chengdu University
item Gou, Xinhua - Chengdu University

Submitted to: Bioengineered
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2017
Publication Date: 1/10/2018
Citation: Zhao, L., Zhang, Y., Venkitasamy, C., Pan, Z., Zhang, L., Guo, S., Xiong, W., Xia, H., Liu, W., Gou, X. 2018. Preparation of umami octopeptide with recombined Escherichia coli: feasibility and challenges. Bioengineered. 9:166-169.

Interpretive Summary: It was reported that LGAGGSLA showed umami taste, but its flavor was controversial due to the inconsistency in the verification results. Use of synthesized LGAGGSLA to confirm its taste might be the most likely reason for the flavor disputation. Based on this speculation, we tried to prepare bio-source LGAGGSLA to further confirm its taste. However, we just obtained the fusion protein in our previous work, which had to be cleaved by enterokinase (EK) to obtain LGAGGSLA. Based on our previous investigation of structuring recombinant Escherichia coli for preparing LGAGGSLA, the mass and volume yields of key processing steps in the preparation of LGAGGSLA was calculated in this study, and the cleavage conditions of using EK to hydrolyze the fusion protein was optimized with response surface method. The results showed that using present recombinant bacteria to prepare LGAGGSLA is not economically viable for industrial production. The optimal cleavage conditions of preparing LGAGGSLA were: EK dosage 2.00 µL/mg, cleavage time 15 h, and cleavage temperature 24 °C. The maximum cleavage ratio of LGAGGSLA is 93.1%.

Technical Abstract: The taste of umami peptide H-Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala-OH (LGAGGSLA) is controversial. One possible reason for this controversy is the use of chemically synthesized LGAGGSLA to confirm its taste. To explore other ways to further confirm the flavor of LGAGGSLA, we developed a new strategy to prepare a bio- source peptide by adopting a gene engineering method to express LGAGGSLA in recombinant Escherichia coli. In our previous work, we structured the LGAGGSLA recombinant expression system and optimized the culturing conditions for preparing a fusion protein. However, the fusion protein was not cleaved by enterokinase to obtain LGAGGSLA. Because the cleavage conditions of commercial enterokinase were not specific and recombinant engineered bacteria had the potential to be used in industrial processes, in this addendum, we calculated the mass and volume yields of key processing steps in the preparation of LGAGGSLA, and established a model of cleavage conditions with the cleavage ratio of LGAGGSLA. When the LGAGGSLA was confirmed to show umami taste, it is considered as a new umami or umami enhancer. The gene information of LGAGGSLA should have a great potential in the development of new flavor product and food product containing high umami flavor.