Production of a recombinant heat-stable sweet protein.

• Main Author: Lim, Ting Hong.
• Other Authors: Liu Chuan Fa
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/49275
• Institution: Nanyang Technological University

Brazzein, isolated from West African fruits, is a natural sweetener that has potential positive health impact. It is very small in size with only 54 amino acids but is 500 times sweeter than a 10% sucrose solution on a weight basis. The protein contains 4 disulfide bonds which provide stability in a wide range of temperature and pH. Previous research shows that expression of brazzein in different cell systems is not cost effective. In our project, we first tried to express brazzein in E. coli as itself or as a fusion protein. The results show that brazzein alone did not express in E. coli. However, brazzein fused with intein did express in E. coli and had a considerable yield of product. Next we tried to ligate the brazzein genes with a yeast plasmid (YEP181-PGK-P7) and transform into wild type yeast. Our ultimate purpose is to design a baking yeast system which is capable to produce the heat-stable sweet protein. However, we failed to ligate the genes into the yeast plasmid due to time limitation and some other issues. In future, some adjustments and improvements can be done in the protocol to reach the goal.