# Optimising environmental factors for maximal lactate productivity in Synechocystis sp. PCC 6803 through a design of experiments approach

## TL;DR

This study uses a design of experiments approach to optimize environmental factors for maximum lactate production in Synechocystis sp. PCC 6803.

## Contribution

The study introduces a DOE-based method to simultaneously optimize multiple environmental factors for enhanced lactate productivity.

## Key findings

- Light intensity, glycerol concentration, and light–dark cycle significantly affect lactate production.
- Optimized conditions increased lactate titre and yield by 6.3- and 7.4-fold, respectively.

## Abstract

Genetic and metabolic engineering of Synechocystis sp. PCC 6803 has given rise to strains that produce a variety of bio-chemicals. Despite these successes, improvements in productivity metrics are required to achieve economically viable bio-production of carbon dioxide-derived compounds. Previously, environmental factors have been leveraged to increase product yields. Here, we optimise multiple environmental factors simultaneously using Design of Experiments (DOE) principles and find conditions that maximise L-lactate production. Light intensity, glycerol concentration, and light–dark cycle were found to be significant factors. Optimising these conditions resulted in a 6.3- and 7.4-fold increase in titre and yield. The results detailed here could have implications for metabolic engineering of, and bioprocesses using, Synechocystis sp. PCC 6803. In the future, DOE-mediated optimisation of environmental conditions could effectively maximise product titres from different production strains, or the enhanced conditions described here could be directly implemented in other metabolic engineering projects.

The online version contains supplementary material available at 10.1186/s13068-025-02718-2.