Co-cultures with integrated in situ product removal for lactate-based propionic acid production

Ludwig Selder,Alagappan Lakshmanan,Nikolai Jürgensen,Wael Sabra,An-Ping Zeng

doi:10.1007/s00449-020-02300-0

Ludwig Selder, Alagappan Lakshmanan + Show 3 more

Open Access

https://doi.org/10.1007/s00449-020-02300-0

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Abstract

Propionic acid (PA) is a valuable organic acid for the food and feed industry, but no bioproduction at industrial scale exists so far. As product inhibition is a major burden for bioprocesses producing organic acids, in situ product removal (ISPR) is desirable. Here, we demonstrate a new strategy to produce PA with a co-culture coupled with ISPR using electrodialysis. Specifically, Bacillus coagulans first produces lactic acid (LA) from sugar(s) and LA is converted to PA using Veillonella criceti. Applying ISPR to the mentioned co-culture, the specific PA yield was increased from 0.35 to 0.39 g g−1 compared to no ISPR usage. Furthermore, the productivity was increased from 0.63 to 0.7 g L−1 h−1 by applying ISPR. Additionally, it was shown that co-consumption of xylose and glucose led to a higher PA productivity of 0.73 g L−1 h−1, although PA yield was only increased slightly up to 0.36 g g−1.

Highlights

Propionic acid (PA) is an important compound used in a variety of industries, e.g., for the production of food, polymers and pharmaceuticals [1, 38]
Production of lactate exceeding the glucose consumption between 10 and 20 h of fermentation time is obviously due to use of complex medium components
As it can be determined from the specific yield, almost all of the substrate is converted into lactate, and only a small fraction is used for energy and biomass generation

Summary

Introduction

Propionic acid (PA) is an important compound used in a variety of industries, e.g., for the production of food, polymers and pharmaceuticals [1, 38]. Up to now, the vast majority of PA is produced via petrochemical processes, namely the Reppe and Larsson process [15]. To steer the chemical industry towards sustainable production routes, biotechnological processes have been studied to produce PA from bio-based resources [16; 35]. The biotechnological route cannot compete economically with the petrochemical production process, due to limited yield, productivity, and high costs of product recovery when using bio-based substrates. The vast majority of studies concerning microbial PA production have been conducted with bacteria of the Propionibacteria species. Several strains such as Propionibacterium acidipropionici, P. shermanii,and P

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