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United States Department of Agriculture

Agricultural Research Service

Title: Cloning and Characterization of a Sucrase from Leuconostoc Mesenteroides

Authors
item Holt, Scott
item Cote, Gregory

Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 16, 1997
Publication Date: N/A

Interpretive Summary: American agribusiness faces foreign challenges in an extremely competitive global marketplace due to free-trade agreements and the formation of European cooperatives. In addition to foreign competition, new value-added businesses are needed for American farmers. To remain competitive in the world marketplace and establish new value-added businesses, it is essential that research efforts be focused on the efficient conversion of surplus American agricultural commodities such as sugar into higher-value commercial products that may be used to replace goods currently imported from foreign countries. The U.S. imports approximately 20 million pounds of the food additive Gum arabic annually, however, this market could be partially replaced by a domestically produced gum known as alternan. Alternan is a natural gum made from sugar with the aid of microorganisms. Currently, the production of alternan is not economically competitive due to low-yielding microorganisms. Development of a more cost efficient alternan production process is essential to initiate an alternan industry. In this study, we have isolated a sugar-degrading gene from the alternan-producing microorganism. The information obtained from the isolated gene may be used to engineer a more efficient alternan- producing microorganism. This study provides both basic knowledge as well as practical information of interest to commercial manufacturers.

Technical Abstract: A sucrase gene from Leuconostoc mesenteroides was cloned and expressed in Escherichia coli. The cloned enzyme did not show dextransucrase or sucrose phosphorylase activity. HPLC and GC-MS analyses of the sucrase products indicated the presence of fructose and glucose in equimolar amounts. IPTG induction did not increase sucrase activity in E. coli indicating that the cloned gene may be transcribed from its own promoter. To our knowledge, this is the first sucrase cloned from L. mesenteroides that has invertase activity.

Last Modified: 10/1/2014
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