Bacterial exudates as growth‐promoting agents for the cultivation of commercially relevant marine microalgal strains

• DOI: 10.1111/jwas.12910
• Publication Date: 2022-07-19T05:39:46Z
• Authors: Justine Sauvage; Gary H. Wikfors; Mark S. Dixon; Diane Kapareiko; Koen Sabbe; Xiaoxu Li; Alyssa Joyce
• Keywords: Exudate; Marine bacteriophage; Bacterial growth; Hatchery

Abstract In laboratory and industrial cultivation of marine microalgae, it is customary to enrich cultures with macronutrients (N, P), chelated trace metals, vitamins at ~10 4 × concentrations found in nature obtain high culture densities. Other naturally occurring growth‐promoting compounds local seawater are not enriched remain environmental concentrations. Microalgae may thus be deprived the mutualistic contributions co‐occurring microorganisms which they have evolved complex chemical relationships. present study, we assess direct (mixed bacteria–microalgae cultivation) indirect (exposure exudates only, without physical contact) effects 10 bacterial strains on growth five microalgal used as feeds aquaculture hatcheries. Bacterial were selected based upon previously reported characteristics plants or known release probiotics. Our experiments demonstrate superior stimulation by exudates, presence bacteria that produced these exudates. However, response exudate enrichment was dependent microalgae strain pairing. Exudates from Bacillus , Mesorhizobium Phaeobacter most effective, 22%–69% increases specific rate. Such findings indicate accelerate rate‐limiting processes governing nutrient acquisition, assimilation, anabolism, possibly algal exopolymeric substances. Maximal cell density, however, remained constrained macronutrient limitation. Scaled‐up trials an oyster hatchery confirmed practical benefit medium demonstrated suitability exudate‐enriched feed hatchery‐reared bay scallops. This work presents a promising strategy improve media formulations using components promoters, first such study identify pairings relevance for production.