Boosting D-lactate production in engineered cyanobacteria using sterilized anaerobic digestion effluents

Whitney D Hollinshead; Arul M Varman; Le You; Zachary Hembree; Yinjie J Tang

doi:10.1016/j.biortech.2014.07.003

Boosting D-lactate production in engineered cyanobacteria using sterilized anaerobic digestion effluents

Bioresour Technol. 2014 Oct:169:462-467. doi: 10.1016/j.biortech.2014.07.003. Epub 2014 Jul 10.

Authors

Whitney D Hollinshead¹, Arul M Varman², Le You¹, Zachary Hembree¹, Yinjie J Tang³

Affiliations

¹ Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
² Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, USA; Biological and Materials Science Center, Sandia National Laboratories, Livermore, CA 94550, USA.
³ Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, USA. Electronic address: yinjie.tang@seas.wustl.edu.

PMID: 25084044
DOI: 10.1016/j.biortech.2014.07.003

Abstract

Anaerobic digestion (AD) is an environmentally friendly approach to waste treatment, which can generate N and P-rich effluents that can be used as nutrient sources for microalgal cultivations. Modifications of AD processes to inhibit methanogenesis leads to the accumulation of acetic acid, a carbon source that can promote microalgal biosynthesis. This study tested different AD effluents from municipal wastes on their effect on D-lactate production by an engineered Synechocystis sp. PCC 6803 (carrying a novel lactate dehydrogenase). The results indicate that: (1) AD effluents can be supplemented into the modified BG-11 culture medium (up to 1:4 volume ratio) to reduce N and P cost; (2) acetate-rich AD effluents enhance D-lactate synthesis by ∼ 40% (1.2g/L of D-lactate in 20 days); and (3) neutral or acidic medium had a deleterious effect on lactate secretion and biomass growth by the engineered strain. This study demonstrates the advantages and guidelines in employing wastewater for photomixotrophic biosynthesis using engineered microalgae.

Keywords: Municipal waste; Photomixotrophic; Synechocystis 6803; d-lactate dehydrogenase.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Acetates / pharmacology
Anaerobiosis / drug effects
Hydrogen-Ion Concentration
Lactic Acid / biosynthesis*
Metabolic Engineering / methods*
Refuse Disposal*
Sewage / microbiology
Sterilization*
Synechocystis / drug effects
Synechocystis / growth & development
Synechocystis / metabolism*
Waste Disposal, Fluid*
Wastewater / microbiology

Substances

Acetates
Sewage
Waste Water
Lactic Acid