Statistical optimization of levan: Influence of the parameter on levan structure and angiotensin I-converting enzyme inhibitory

Amir Bouallegue; Angela Casillo; Fatma Chaari; Donatella Cimini; Maria Michela Corsaro; Rafik Bachoual; Semia Ellouz-Chaabouni

doi:10.1016/j.ijbiomac.2020.04.232

Statistical optimization of levan: Influence of the parameter on levan structure and angiotensin I-converting enzyme inhibitory

Int J Biol Macromol. 2020 May 1:158:945-952. doi: 10.1016/j.ijbiomac.2020.04.232. Online ahead of print.

Authors

Amir Bouallegue¹, Angela Casillo², Fatma Chaari³, Donatella Cimini⁴, Maria Michela Corsaro², Rafik Bachoual⁵, Semia Ellouz-Chaabouni⁶

Affiliations

¹ Laboratory for the Improvement of Plants and Valorization of Agroressources, National School of Engineering of Sfax (ENIS), University of Sfax, Sfax 3038, Tunisia; Faculty of Sciences of Gabes, University of Gabes, Gabes, Tunisia. Electronic address: amir.bouallegue@enis.tn.
² Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy.
³ Laboratory for the Improvement of Plants and Valorization of Agroressources, National School of Engineering of Sfax (ENIS), University of Sfax, Sfax 3038, Tunisia.
⁴ Department of Experimental Medicine, Section of Biotechnology, University of Campania "Luigi Vanvitelli", via de Crecchio 7, I-80138 Napoli, Italy.
⁵ Laboratory for the Improvement of Plants and Valorization of Agroressources, National School of Engineering of Sfax (ENIS), University of Sfax, Sfax 3038, Tunisia; Faculty of Sciences of Gabes, University of Gabes, Gabes, Tunisia.
⁶ Laboratory for the Improvement of Plants and Valorization of Agroressources, National School of Engineering of Sfax (ENIS), University of Sfax, Sfax 3038, Tunisia; Common Service Unit of Bioreactor Coupled with an Ultrafilter, National School of Engineering, Sfax University, P.O. Box 1173, 3038 Sfax, Tunisia. Electronic address: Semia.Chaabouni@enis.rnu.tn.

PMID: 32360961
DOI: 10.1016/j.ijbiomac.2020.04.232

Abstract

Based on Plackett-Burman design, steepest ascent method, and Box-Behnken design, statistical optimization for B. subtilis AF17 for levan production was carried out. Sucrose, tryptone and initial pH were found to be the most significant parameter (P < 0.05) for levan production. Result showed that the optimum condition was sucrose 162.5 g/L, tryptone 10 g/L, initial pH 7 and maximum yield was 7.9 ± 0.18 g/L in 72 h fermentation. Purified levan was characterized using various physicochemical techniques such as GC-MS, ¹H NMR, ¹³C NMR spectroscopy and SEC/TDA. Based on this data, the structure of levan was independent of initial culture conditions. The biomedical potential of the isolated Bacillus subtilis A17 levan for its angiotensin-I converting enzyme (ACE) inhibition activities was exploited in vitro. Interestingly, levan possessed an important angiotensin I converting enzyme (ACE) inhibitory 81.1 ± 4.1% at 4 mg/mL. The overall, data suggested that levan presents a promising natural source of antihypertensive agents.

Keywords: Bacillus subtilis AF17; Biological activity; Levan; Optimization; Response surface methodology.