Health benefits of microalgae and their microbiomes

Abstract

Microalgae comprise a phylogenetically very diverse group of photosynthetic unicellular pro-and eukaryotic organisms growing in marine and other aquatic environments. While they are well explored for the generation of biofuels, their potential as a source of antimicrobial and prebiotic substances have recently received increasing interest. Within this framework, microalgae may offer solutions to the societal challenge we face, concerning the lack of antibiotics treating the growing level of antimicrobial resistant bacteria and fungi in clinical settings. While the vast majority of microalgae and their associated microbiota remain unstudied, they may be a fascinating and rewarding source for novel and more sustainable antimicrobials and alternative molecules and compounds. In this review, we present an overview of the current knowledge on health benefits of microalgae and their associated microbiota. Finally, we describe remaining issues and limitation, and suggest several promising research potentials that should be given attention.

New dienelactone hydrolase from microalgae bacterial community-Antibiofilm activity against fish pathogens and potential applications for aquaculture

“…In our previously published datasets we detected a surprisingly high diversity of quorum quenching agents that are known to be involved in disturbing/interrupting the synchronization of bacteria within a community 21 , 28 , 30 , 32 . In total, almost 638 enzyme candidates were predicted, most of them hydrolases (number of hits: 321).…”

“…However, biofilm formation can be attacked at various key positions, for example by biotechnological approaches targeting the capability of adherence, the production of extracellular polymeric substances, or by disturbing the bacterial communication. Although, the diversity of known enzymes and microbes affecting biofilms and potential pathogenic microorganisms is still rather limited, a promising source for finding novel bioactive compounds against biofilm-forming fish pathogenic bacteria is the fascinating world of microalgae and their associated bacterial communities 20 , 21 . Previous research showed that microalgae are surrounded by a natural community of beneficial bacteria, including interesting strategies that make this microbiota able to out-compete undesirable opportunistic bacteria such as fish pathogens or even human pathogens 21 .…”

“…Instead of looking for bioactive compounds in microalgae cultures directly, we hypothesized that metagenomic datasets of microalgae-bacteria communities encode antimicrobial compounds. Previously, we have analyzed already published datasets of microalgae and their bacterial metagenome and identified several mechanisms and biofilm-reducing candidates (Supplemental Table S1 , 21 ). The analysis of metagenomes of Scenedesmus communis ( quadricauda ), Chlorella saccharophila and Micrasterias crux-melitensis, available at IMG/MER ( https://img.jgi.doe.gov ), unveiled e.g., imidazolone-propionases, 6-phosphogluconolactonases, metal-dependent hydrolases, and most importantly dienelactone hydrolases (Dlh) potentially associated with quorum quenching (QQ) and significant impact on quorum sensing (QS) related to pathogen infection ( 21 , 28 , 31 Supplemental Table S1 ).…”

Therapeutic Potentials of Microalgae and Their Bioactive Compounds on Diabetes Mellitus

“…Microalgae biomass and their bioactive compounds, such as polyunsaturated fatty acids (PUFAs), pigments, amino acids, peptides, scytonemins, pterins and phenolic compounds, have been shown to demonstrate a wide range of therapeutic effects [ 18 ]. Importantly, some of the microalgae and bioactive compounds exhibit antioxidant, anti-inflammatory, and immune-modulatory properties, and improve insulin sensitivity that could potentially alleviate diabetes mellitus [ 18 , 19 , 20 , 21 ]. Table 1 summarizes the bioactive compounds present in various sources that have been particularly identified in certain microalgae species and their activity on diabetes mellitus.…”