Isolation and selection of fructose-consuming lactic acid bacteria associated with coffee bean fermentation

ABSTRACT

The discrepancy between glucose over fructose metabolism during coffee fermentation can delay the drying process and stimulate the development of undesirable microorganisms. In this study, 26 lactic acid bacteria (LAB) isolated from laboratory-scale coffee fermentation were screened for their capacity to preferentially consume fructose over glucose and identified by 16S rDNA sequencing. Ten fructose-consuming isolates were identified as Levilactobacillus brevis (n = 8) and Pediococcus pentosaceus (n = 2). The growth characteristics of three Lev. brevis strains (LPBF01, LPBF03 and LPBF06) were classified as “facultatively” fructophilic bacteria, i.e., they grew on glucose without an external electron acceptor (oxygen, fructose, or pyruvate) but grew more rapidly on fructose. Lev. brevis LPBF03 was characterized for producing a high content of flavor-active esters (1-butanol, benzaldehyde, 2-nonenal, and 2-pentanone) and now being targeted as a good candidate to improve fructose consumption and aroma formation during coffee fermentation.

KEYWORDS:

• Coffee processing
• fructophilic lactic acid bacteria
• fructose
• stirred-tank bioreactor
• wet processing

Acknowledgments

The authors gratefully acknowledge the support provided by Brazilian Council for Scientific and Technological Development (Grant Number 303254/2017-3).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the CNPQ [303254/2017-3].