Effect of solid-state fermentation and ultrasonication processes on antimicrobial and antioxidant properties of algae extracts

Ernesta Tolpeznikaite; Vytaute Starkute; Egle Zokaityte; Modestas Ruzauskas; Renata Pilkaityte; Pranas Viskelis; Dalia Urbonaviciene; Romas Ruibys; João M Rocha; Elena Bartkiene

doi:10.3389/fnut.2022.990274

Effect of solid-state fermentation and ultrasonication processes on antimicrobial and antioxidant properties of algae extracts

Front Nutr. 2022 Aug 26:9:990274. doi: 10.3389/fnut.2022.990274. eCollection 2022.

Authors

Ernesta Tolpeznikaite¹, Vytaute Starkute^{1

2}, Egle Zokaityte^{1

2}, Modestas Ruzauskas^{3

4}, Renata Pilkaityte⁵, Pranas Viskelis⁶, Dalia Urbonaviciene⁶, Romas Ruibys⁷, João M Rocha^{8

9}, Elena Bartkiene^{1

2}

Affiliations

¹ Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, Kaunas, Lithuania.
² Department of Food Safety and Quality, Faculty of Veterinary, Lithuanian University of Health Sciences, Kaunas, Lithuania.
³ Department of Anatomy and Physiology, Faculty of Veterinary, Lithuanian University of Health Sciences, Kaunas, Lithuania.
⁴ Institute of Microbiology and Virology, Faculty of Veterinary, Lithuanian University of Health Sciences, Kaunas, Lithuania.
⁵ Marine Research Institute, Klaipeda University, Klaipeda, Lithuania.
⁶ Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Babtai, Lithuania.
⁷ Institute of Agricultural and Food Sciences, Vytautas Magnus University, Agriculture Academy, Kaunas, Lithuania.
⁸ Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal.
⁹ Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.

Abstract

Algal biomass (AB) is prospective source of valuable compounds, however, Baltic Sea macroalgae have some challenges, because of their high microbial and chemical contamination. These problems can be solved, by using appropriate technologies for AG pre-treatment. The aim of this study was to evaluate the influence of two pre-treatments, solid-state fermentation with the Lactiplantibacillus plantarum LUHS135 and ultrasonication, on the antioxidant and antimicrobial characteristics of macro- (Cladophora rupestris, Cladophora glomerata, Furcellaria lumbricalis, Ulva intestinalis) and Spirulina (Arthrospira platensis) extracts. Also, combinations of extracts and LUHS135 were developed and their characteristics were evaluated. The total phenolic compound content was determined from the calibration curve and expressed in mg of gallic acid equivalents; antioxidant activity was measured by a Trolox equivalent antioxidant capacity assay using the DPPH^• (1,1-diphenyl-2-picrylhydrazyl), ABTS^•+ 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (Ferric Reducing Ability of Plasma) discoloration methods. Antimicrobial activity was measured by using agar well diffusion assay and in a liquid medium. The highest DPPH^• and ABTS^•+ was shown by C.rupestris and F.lumbricalis extract × LUHS135 combinations, the highest FRAP - by non-pretreated C.rupestris and F.lumbricalis extract × LUHS135 combinations. Ultrasonicated samples inhibited four out of seven tested pathogens. Finally, the tested pre-treatments showed good perspectives and can be recommended for AB valorization.

Keywords: algae; antimicrobial properties; antioxidant properties; extracts; lactic acid bacteria; solid-state fermentation; ultrasonication.