The Sequencing, Assembly and Annotation of Sugar Producing Green Algae and the Design of a Low Cost Turbidostat

Abstract

The number of sequenced genomes continues to rise at an astounding rate, however, only thirty-one green algae genomes have been sequenced to date. In this work, two green algae, Micractinium conductrix SAG 241.80 (formerly named Chlorella sp. SAG 241.80) and Chlorella sorokiniana UTEX 1602, have had their genomes sequenced and assembled de novo and functionally annotated. These two new genomes were used to investigate the genes responsible for a sugar-secreting phenotype previously described in M. conductrix SAG 241.80. When grown at a lowered pH of approximately 5.7, M. conductrix SAG 241.80 releases maltose and glucose outside of the cell, while at pH 7.6, sugar production is minimal. An additional green alga with a high sugar-releasing phenotype was isolated from the environment (Scenedesmus sp. PABB004) and found to release a quantity of sugars five-fold higher than what was found for M. conductrix SAG 241.80. Additionally, this strain did not require the low pH of 5.7 for sugar release, and produced these sugars at a physiological pH of 7.0. This work, as well as additional efforts toward developing a low-cost turbidostat for performing evolutionary experiments in microbes will be presented.