# Enhancing Acetate Utilization in Phaeodactylum tricornutum through the Introduction of Acetate Transport Protein

## TL;DR

Scientists improved the ability of a diatom to use acetate by introducing a yeast transporter gene, which boosted growth but altered lipid production.

## Contribution

The introduction of the ADY2 gene from yeast enabled acetate utilization in P. tricornutum, enhancing growth and lipid content.

## Key findings

- Transformants showed a 1.7- to 2.0-fold growth increase at 0.01 M NaAc compared to wild-type.
- Acetate utilization reduced photosynthetic efficiency and electron transport rates.
- Crude lipid content increased, with a shift in fatty acid profiles favoring C16:1n-7 over EPA.

## Abstract

The diatom Phaeodactylum tricornutum, known for its high triacylglycerol (TAG) content and significant levels of n-3 long chain polyunsaturated fatty acids (LC-PUFAs), such as eicosapentaenoic acid (EPA), has a limited ability to utilize exogenous organic matter. This study investigates the enhancement of acetate utilization in P. tricornutum by introducing an exogenous acetate transport protein. The acetate transporter gene ADY2 from Saccharomyces cerevisiae endowed the organism with the capability to assimilate acetate and accelerating its growth. The transformants exhibited superior growth rates at an optimal NaAc concentration of 0.01 M, with a 1.7- to 2.0-fold increase compared to the wild-type. The analysis of pigments and photosynthetic activities demonstrated a decline in photosynthetic efficiency and maximum electron transport rate. This decline is speculated to result from the over-reduction of the electron transport components between photosystems due to acetate utilization. Furthermore, the study assessed the impact of acetate on the crude lipid content and fatty acid composition, revealing an increase in the crude lipid content and alterations in fatty acid profiles, particularly an increase in C16:1n-7 at the expense of EPA and a decrease in the unsaturation index. The findings provide insights into guiding the biomass and biologically active products production of P. tricornutum through metabolic engineering.