2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Engineered Cyanobacteria as a Potential Organic Degrader for Wastewater Treatment

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Mr. Yiqi Cao (Presenter)
Mr. Pengfei Xia
Dr. Baiyu (Helen) Zhang, Memorial University
Dr. Bing Chen, Memorial University
Mr. Shuguang Wang

Engineered Cyanobacteria as a Potential Organic Degrader for Wastewater Treatment

Yiqi Cao1, Pengfei Xia2, Baiyu Zhang*1, Bing Chen1, Shuguang Wang*2

1 Northern Region Persistent Organic Pollution Control (NRPOP) Laboratory, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL A1B 3X5, Canada

2 School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China

During the secondary wastewater treatment, bacteria in the activated sludge could break down organic matter into carbon dioxide (CO2), a greenhouse gas resulting in global warming. It then will be ideal if the process can assimilate the released CO2 to control its emission. Previous studies indicated that cyanobacteria would play an indispensable role in controlling climate change due to their vigorous ability of capturing and fixing CO2 through CO2 Concentrating Mechanism (CCM). It is thus promising if cyanobacteria can be integrated with the secondary wastewater treatment system. However, most existing cyanobacteria are photoautotrophy and can hardly metabolize organic carbons directly. To achieve the target of using cyanobacteria for organics degradation in wastewater, efforts are needed to obtain engineered cyanobacteria to utilize simple organics like sugars as carbon sources.

In this study, the cyanobacteria strain Synechococcus elongates PCC7942 (S. elongates) was chosen due to its high genetic manipulation capacity. Three types of sugars (i.e., glucose, xylose and arabinose) were selected as carbon sources, respectively. The pivotal modules including the sugar transporters and peripheral metabolic processes were introduced into the genome of S. elongates. Results showed that the engineered S. elongates strain led to organics (i.e., sugars) consumption for biomass formation successfully. In addition, based on the exploration of the growth state of engineered S. elongates under the diurnal light condition (with the light/dark cycle), the sugar consumption could be carried out when using natural light. The research outputs paved a road for future applications of cyanobacteria for CO2 emission control during the secondary wastewater treatment.