Engineering Cyanobacteria For Higher Yields

Scientists have engineered a cyanobacteria mutant that can produce higher amounts of glucosylglycerol.

AsianScientist (Dec. 22, 2014) – Researchers have developed an efficient method for the production of the useful solute, glucosylglycerol (GG). This research has been published in Applied Microbiology and Biotechnology.

Glucosylglycerol (GG) has a range of potential applications in health, pharmacy and cosmetics due to its physiological, protein-stabilizing and antioxidative properties. In addition to chemical synthesis and enzymatic catalysis, GG can be produced as a protective osmolyte in salt-stressed bacteria, such as the cyanobacterium Synechocystis sp. PCC 6803. However, low efficiency and high cost makes scalable production of GG difficult.

Taking a genetic engineering approach, the researcher team from the Microbial Metabolic Engineering Group at Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, improved the production and secretion of GG in Synechocystis by first disrupting both the ggtC and ggtD genes—which encode the subunits of a GG uptake transporter—as well as the ggpR gene, which encodes a repressor for GG synthesis.

They confirmed that the rapid GG release from salt-stressed cells of Synechocystis depended on the ion gradient across the cell membrane. They further increased the GG titer of the mutant to ~1 g/l by the semi-continuous culturing. The researchers also proved the feasibility of an agar gel encapsulation method in supporting cell growth and the GG production of Synechocystis under semi-continuous culturing conditions.

The article can be found at: Tan et al. (2014) Photosynthetic and Extracellular Production of Glucosylglycerol by Genetically Engineered and Gel-encapsulated Cyanobacteria.

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Source: Chinese Academy of Sciences.
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