Team:Lethbridge/Cyanobacteria Growth

Results

Cyanobacteria Growth

Establishing Growth and Handling Conditions for Synechococcus elongatus

Overview

In previous years, our team has established standard protocols and handling procedures for working with Escherichia coli. This year, we added a new organism, Synechococcus elongatus, to our repertoire and invested the necessary time for the development of detailed protocols to ensure optimal handling of this organism.

Experimental Setup and Results

We constructed a Do-It-Yourself shaking and lighting system to optimize the growth of S. elongatus (Fig. 1). S. elongatus requires light and CO2 for growth, so we monitored the growth of S. elongatus when aerated with a CO2 bubbler and without aeration. The cultures were grown at room temperature with shaking under fluorescent lighting at 400 and 700 nm. The optical density of the cultures was monitored at 750 nm for over 10 days (Fig. 2). The growth of S. elongatus progressed much faster when the culture was aerated than when it was not. This was a good indication to us that shaking does not provide enough aeration for optimal growth of S. elongatus and that using a CO2 bubbler would allow for faster growth.

Figure 1. Shaking and lighting system used to maintain proper growth conditions for S. elongatus. The system allows for CO2 aeration of culture flasks and direct lighting from a suspended fluorescent bulb that emits light at 400 and 700 nm.

Figure 1. Growth curves of S. elongatus monitored by optical density at 750 nm, grown with and without aeration provided by a CO2 bubbler.

We also tested conditions necessary for preparing glycerol stocks of S. elongatus. Glycerol stocks were prepared with 20%, 30%, and 40% glycerol and all stocks were able to be used to start cultures for growth. With this data, we now have working protocols that can be used to grow S. elongatus and test our constructs for enhanced glucose production and export.