ANUSUYA P BIOSENSOR uses RAS system.pptx

ANUSUYA P BIOSENSOR uses RAS system.pptx

1. IMPLEMENTATION OF BIOSENSOR FOR PATHOGEN CONTROL IN RAS ANUSUYA P DAQC – 1 U24TN03002MF002 AQC 516 - Recirculating Aquaculture System

2. Biosensors in aquaculture are integrated devices that use biological recognition elements and transducers to monitor water quality, fish health and product safety, offering real-time, sensitive and portable solutions to traditional methods.  They detect a range of substances including pathogens, pollutants like heavy metals and metabolic biomarkers enabling proactive management and enhancing food safety in aquaculture systems.  INTRODUCTION

3. BIOSENSORS IN RAS RAS are closed/ semi closed systems where pathogen introduction and amplification can rapidly affect entire production units; early detection shortens response time and limits spread. Biosensors consist of a biorecognition element (such as antibodies, enzymes, nucleic acids) directly coupled with a transducer that converts biological interactions into measurable electronic signals.

4.   SCHEMATIC OF THE EXPERIMENTAL RAS CONTROL PROCESS

5. WORKING PRINCIPLE FOR PATHOGEN DETECTION (a) Recognition of Pathogen The biosensor uses a specific recognition element that binds only to the target pathogen or its biomarker. Antibody-based → Detects specific proteins on pathogen surface. DNA/RNA probes → Detect genetic material of pathogens. Aptamers → Synthetic nucleic acids that bind to toxins or cells. Whole-cell sensing → Microbes engineered to glow or change behaviour in presence of pathogen metabolites.

6. (b) Signal Transduction Once binding occurs, the interaction produces a measurable change: Electrochemical → Change in current, voltage, or impedance. Optical → Change in fluorescence, absorbance, or color. Piezoelectric → Change in vibration frequency when pathogen binds. Thermal → Heat released or absorbed in reaction.

7. (c) Signal Processing The raw signal is amplified and processed into clear data. (d) Output and Decision-Making The farmer or automated system receives the alert. Action required : water treatment, UV sterilization, probiotic dosing, or flow adjustment.

8. MODES OF PATHOGEN CONTROL USING BIOSENSORS Early Warning and Preventive Control Mode of Action : Biosensors detect the presence of pathogens at very low concentrations before they cause clinical disease. How it works : Continuous monitoring of RAS water with biosensors (e.g., electrochemical or CRISPR-based) sends alerts when a pathogen is detected. Control outcome: Farmers can immediately isolate affected tanks. Apply disinfection (UV, ozone) or probiotic treatments. Prevents the spread of the pathogen to the entire system. Example: A WSSV biosensor in shrimp RAS detects viral DNA early, allowing farmers to stop water circulation and treat before mass mortality.

9. 2. Real-Time Monitoring and Dynamic Control Mode of Action: Biosensors continuously track pathogen load and water quality, giving real-time data. How it works: The biosensor is connected to IoT/AI-based systems that automatically adjust RAS functions. Control outcome: Automatic dosing of disinfectants, probiotics, or immunostimulants when pathogen levels rise. Real-time control of aeration, pH, and biofiltration to reduce pathogen survival. Example: Electrochemical biosensor linked to an automated dosing system that releases probiotic bacteria when Vibrio counts exceed safe levels.

10. 3. Targeted and Specific Pathogen Control Mode of Action: Biosensors identify the exact pathogen species/strain instead of just total microbial load. How it works: Immunosensors/aptamer sensors can differentiate between harmless Vibrio and pathogenic Vibrio harveyi . This prevents unnecessary use of broad-spectrum treatments. Control outcome: Enables precision treatment (e.g., specific bacteriophage therapy). Reduces antibiotic misuse and antimicrobial resistance. Example: An aptamer-based biosensor detects Aeromonas hydrophila specifically, triggering only targeted interventions.

11. 4. Integrated Biosecurity and System-Level Control Mode of Action: Biosensors act as part of an integrated pathogen surveillance system. How it works: Installed at water inlets/outlets, fish tanks, and biofilters. Prevents entry of pathogens from external water sources. Ensures pathogens don’t exit the farm (environmental biosecurity). Control outcome: Reduces pathogen recirculation and cross-contamination. Provides traceability and compliance with regulatory biosecurity standards. Example: Multi-sensor platform in RAS inlet pipeline prevents the entry of Vibrio and Saprolegnia spores into the culture tanks.

12. 5.Decision-Support and Predictive Control Mode of Action: Biosensors generate continuous datasets, which feed into predictive models. How it works: Data analysis (AI/ML) predicts when pathogen levels are likely to reach a dangerous threshold. Farmers get alerts before the outbreak actually happens. Control outcome: Shifts disease management from reactive (after outbreak) to proactive (before outbreak). Example: Biosensor data + predictive analytics warns of a Vibrio bloom 48 hours in advance, allowing early preventive measures.

13. Matrix complexity & biofouling : aquaculture water (organic load, biofilms) affects sensor stability and leads to drift — reported across electrochemical and photonic platforms. Anti-fouling designs and routine cleaning are essential. False positives/fragment detection: nucleic-acid-based sensors may detect non-viable particle fragments (environmental DNA/RNA) — necessitates confirmatory testing and context-aware thresholds. Regulatory acceptance & standardization: regulators often require validated PCR methods for reporting; biosensors currently augment surveillance rather than replace confirmatory diagnostics. LIMITATIONS & GAPS

14. Biosensors in aquaculture provide fast, real-time detection of pathogens and environmental changes, helping to prevent disease outbreaks. They enable precise treatment and water quality management, reducing antibiotic use and supporting sustainability. Integrated with smart technology, biosensors offer continuous monitoring and early warnings, improving fish health and farm productivity. Overall, they are key tools for advancing sustainable, efficient Recirculating Aquaculture Systems (RAS). CONCLUSION

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