INTEGRATED MICROBIAL CONSORTIUM- BASED BIOREMEDIATION OF HARMFUL ALGAL BLOOMS AND AQUACULTURE WASTEWATER: AN ECO-ENGINEERING APPROACH

Abstract

Harmful algal blooms (HABs) are over growth of algae and are considered as the most rapidly intensifying ecological threat to marine and freshwater ecosystems worldwide. Although algal blooms are natural occurring phenomenon which is a result of aquatic productivity driven by toxin-producing or high biomass forming microalgae which leads to ecological, economic and public health impact. This report aims to evaluate algicidal bacteria and build a bacterial consortium which is safe and effective and acts as an eco compatible strategy to inhibit or prevent the growth of HAB-forming species. In this report, we assessed global HAB trends, identified causative algal species and environment and biological drivers of bloom intensification. Based on this, algicidal bacteria was selected focusing on their mechanistic pathways, modes of action, selectivity and safety for environmental application. HABs are caused by 6 major groups which are cyanobacteria (Microcystis aeruginosa), dinoflagellates (Noctiluca scintillans), diatoms (Pseudo-nitzschia), raphidophytes (Heterosigma akashiwo), haptophytes (Phaeocytis globosa) and some chrysophytes. Bacterial taxa such as Pseudoalteromonas, Phaeobacter, Bacillus, Hahella, and Shewanella shows strong algicidal activity via ROS induction, EPS degradation, extracellular enzyme production, secondary metabolite release and disruption of photosynthesis and metabolism. Algicidal bacteria can be considered as an emergent mitigation strategy offering a promising, environmentally compatible solution. This work supports the solution of Algicidal bacteria, which can be used as a consortium by evaluating their safety level, selective targeting of HABs and microbial control potential which will help in future field deployable HAB management.

In parallel, PME-oriented strategies for aquaculture wastewater treatment, especially probiotics, synbiotics, synthetic microbial communities (SynComs), biofloc systems, and omics-guided bioremediation platforms were analyzed for their role in wastewater treatment. Their relevance extends beyond nutrient removal alone. In many cases, the same interventions are discussed in relation to host immune support, microbial community stabilization, and suppression of resistant or opportunistic pathogens. Taken together, this work suggests that carefully assembled and field-deployable microbial consortia could support a more integrated management framework, one that addresses HAB control, wastewater remediation, and AMR mitigation within aquaculture ecosystems without treating those issues as separate engineering targets.