A preliminary study on a novel bioaugmentation technique enhancing lactic acid production by mixed cultures fermentation

Grazia Policastro; Federica Carraturo; Mariacristina Compagnone; Marco Giugliano; Marco Guida; Vincenzo Luongo; Raffaele Napolitano; Massimiliano Fabbricino

doi:10.1016/j.biortech.2021.125595

A preliminary study on a novel bioaugmentation technique enhancing lactic acid production by mixed cultures fermentation

Bioresour Technol. 2021 Nov:340:125595. doi: 10.1016/j.biortech.2021.125595. Epub 2021 Jul 26.

Authors

Grazia Policastro¹, Federica Carraturo², Mariacristina Compagnone³, Marco Giugliano⁴, Marco Guida⁵, Vincenzo Luongo⁶, Raffaele Napolitano⁷, Massimiliano Fabbricino⁸

Affiliations

¹ Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, Naples 80125, Italy. Electronic address: grazia.policastro@unina.it.
² Department of Biology, University of Naples Federico II, via Cintia 21, Naples 80126, Italy. Electronic address: federica.carraturo@unina.it.
³ Department of Chemical Engineering and Food Technologies, Faculty of Sciences, University of Cádiz, 11510 Puerto Real, Cádiz, Spain. Electronic address: mariacristina.compagnone@uca.es.
⁴ Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, Naples 80125, Italy. Electronic address: marco.giugliano5@studenti.unina.it.
⁵ Department of Biology, University of Naples Federico II, via Cintia 21, Naples 80126, Italy. Electronic address: marco.guida@unina.it.
⁶ Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, via Cintia, Monte S. Angelo, Naples I-80126, Italy. Electronic address: vincenzo.luongo@unina.it.
⁷ Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, Naples 80125, Italy. Electronic address: raffaele.napolitano13@studenti.unina.it.
⁸ Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, Naples 80125, Italy. Electronic address: massimiliano.fabbricino@unina.it.

PMID: 34333344
DOI: 10.1016/j.biortech.2021.125595

Abstract

The paper is a preliminary study on the selection of lactic acid producing microorganisms from a mixed microbial population via bioaugmentation. The bioaugmentation technique is based on pH sudden variations occurring in sequential batch steps of a dark fermentation process applied to simple substrates. Different conditions are tested and compared. The structure of microbial communities and concentrations of metabolic intermediates are analyzed to study the possible substrate conversion routes. Obtained results indicate that the initial mixed culture produced a lactic acid percentage of 5% in terms of COD_LA/COD_PRODUCTS. In the most favourable conditions, the selected culture produced a lactic acid percentage of 59%. The analysis of the composition of microbial communities before and after the bioaugmentation processes, indicates that lactic acid production mainly results from the population change to bacteria belonging to the genus Bacillus. Indeed, the relative abundance of Bacilli increased from 0.67%, to 8.40% during the bioaugmentation cycle.

Keywords: Bacilli; Fermentation; Lactic acid; Microbial selection; Mixed cultures.

MeSH terms

Bacteria
Fermentation
Lactic Acid*
Microbiota*

Substances

Lactic Acid