Chinese researchers make cyanobacteria CO2 to glucose conversion breakthrough

In China, recently, a research team from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT), Chinese Academy of Sciences (CAS), identified key factors restricting natural potential of cyanobacteria to directly convert carbon dioxide into glucose and constructed efficient glucose synthesizing photosynthetic cell factories.

The study was published in Nature Communications on June 9. In photoautotrophs, e.g., higher plants and algae, glucose is synthesized as storage for carbon and energy. Glucose metabolism possesses complex interactions with photosystems, disturbs the synthesis and metabolism of pigments, and may even inhibit photosynthetic activities. Therefore, free glucose is rarely synthesized or accumulated in excess in photosynthetic cellular metabolism.

The research team utilized an important cyanobacterium Synechococcus elongatus PCC 7942 as the chassis and identified native glucokinase activity as the bottleneck restricting metabolism potential for glucose synthesis.

Targeted knockout of two glucokinase genes disturbed the carbohydrate metabolism and activated a metabolic flux towards glucose through the sucrose metabolism network. The enhanced glucose synthesis promoted the enrichment of a specific spontaneous genomic mutation on the chromosome of PCC 7942, which facilitates efficient glucose secretion.