Deakin University
Browse

File(s) under permanent embargo

Sensitivity of live microalgal aquaculture feed to singlet oxygen-based photodynamic therapy

journal contribution
posted on 2019-12-01, 00:00 authored by D Malara, L Høj, M Oelgemöller, Martino MalerbaMartino Malerba, G Citarrella, K Heimann
Highly nutritional microalgal species are extensively used in aquaculture as live feedstock. Due to difficulties in maintaining microalgae in axenic conditions, they represent a potential pathogen carrier and disease vector in aquaculture ponds. Photodynamic therapy (PDT) via singlet oxygen (1O2) production is a promising sterilization technique in aquaculture. Here, we report on the sensitivity of aquaculture-relevant microalgae towards 1O2 generated by the cationic photosensitizer TMPyP. Possible PDT sterilization protocols of contaminated microalgae cultures were evaluated using the luminescent bacterium Vibrio campbellii ISO7 as a model aquaculture pathogen. Species-specific sensitivity of microalgae to TMPyP-mediated PDT was demonstrated and found to be strongly influenced by the nature and architecture of their respective cell wall. While cytotoxicity was not evident against Nannochloropsis oculata, toxicity of 1O2 was dose-, time- and light activation-dependent against Tisochrysis lutea, Tetraselmis chui, Chaetoceros muelleri and Picochlorum atomus. The 1O2-resilient N. oculata was sterilized when incubated under light in the presence of V. campbellii ISO7 (up to 107 CFU mL−1) and 20 μM TMPyP; hence, TMPyP-based PDT sterilization of N. oculata could be suitable for aquaculture hatcheries. This study also suggests that PDT using cationic porphyrins such as TMPyP holds potential as an algicidal treatment in aquaria and aquaculture systems (but more research using opportunistic and toxic species is needed for confirmation).

History

Journal

Journal of applied phycology

Volume

31

Pagination

3593 - 3606

Publisher

Springer

Location

[Dordrecht, The Netherlands]

ISSN

0921-8971

eISSN

1573-5176

Language

eng

Publication classification

C Journal article; C1.1 Refereed article in a scholarly journal