Getting rid of undesired odours and off-flavours in aquaculture

Getting rid of undesired odours and off-flavours in aquaculture Two-dimensional photonics – a new view of water analysis

With a strategic focus on water analysis Copenhagen Nanosystems ApS (Cphnano) offers a novel liquid-analysis platform enabled by next-generation cloud computing and a patented photonic sensor that expands the utility of spectrophotometric analytical infrastructure.

This allows a rapid quantifi cation at line, which speeds the response time that decreases waste by reducing downtime or the production of a non-conforming product. Stopping production at the fi rst appearance of the problem means the intervention is deployed only when needed. Th is improves performance and reduces environmental impact through better resource management.

Cphnano is among the participants in the FLAVOUR project, a collaboration between research and industry, to develop a method to detect, prevent, and remove off -fl avours and undesired odours in fi sh farmed in recirculating aquaculture systems (RAS). Geosmin is a naturally occurring taste and aromatic compound. It is a terpene, like, for example, R-limonene, which gives orange peels their strong, characteristic smell. Geosmin is the compound primarily responsible for that unmistakable smell of mud or wet earth, recognised as the “earth odour”. Geosmin is also a terpene produced by microorganisms in soil, specifi cally by the streptomyces genus of the family Streptomycetaceae bacteria, which live in soil and fl ourish with decaying matter and produce many of our antibiotics. Geosmin is also the compound responsible for the earthy taste of beetroot and often contaminates freshwater fi sh. However, something that can be tasty in beetroot can be totally unacceptable in fi sh. Acid can degrade geosmin and, therefore, muddy tasting freshwater fi sh are often liberally doused with lemon juice or vinegar.

Preventing geosmin in the fi rst place is preferable to removing it later

Geosmin-free fi sh are in great demand, and there is a large market for a system that detects geosmin in aquaculture water. Today, the primary method of ridding fi sh of geosmin contamination is by recirculating water in recirculating systems, which consumes substantial amounts of water. Rather than eradicating geosmin contamination, fi sh farmers want to prevent geosmin from tainting fi sh in the fi rst place. Off -fl avour compounds, such as geosmin, are produced by microorganisms and give the fi sh an unpalatable taste, even at very low concentrations. Today, the main solution is to depurate the fi sh in large quantities of clean water for 10–15 days. Unfortunately, the fi sh lose a substantial amount of weight during this period, aff ecting production effi ciency – in addition to the environmental cost of excessive water use.

Th e demand for and production of fi sh is increasing steadily. Aquaculture is a driver in this growth with a projected increase of 37 by 2030. Th e geosmin problem is expected to increase accordingly as more RASs will be implemented to meet this demand which is expected to grow. Th e Nordic countries are a bastion of both technology for aquaculture and the production of fi sh. Implementing the technological solution developed in the FLAVOUR project is expected to increase the profi t at European RAS fi sh farms by EUR 22 million accumulated over three years after the project’s conclusion, assuming geosmin can be removed from the fi sh in half the time taken by other methods. Th e environmental impact, realised by savings in water, is expected to amount to 100 million cubic meters. In addition, a 2 increase in production capacity is projected.

NanoCuvette™ One with a water droplet resting on the patented 2D photonic crystal.

Digital laboratory analyses offers a solution

Cphnano is a Danish labtech company that has developed a new concept of digital laboratory analysis for the laboratory of the future. It was founded in 2015 and develops digital laboratory analyses for simple laboratory equipment. Th e company's vision is to expand the use and increase the value of existing spectrophotometers around the world. To achieve this goal, the company strives to enable as many units as possible to perform state-of-the-art laboratory analysis and diagnostics tests. One of Cphnano‘s core products is a cuvette (NanoCuvette One), which enables regular UV-Vis spectrophotometers to replace dedicated microvolume instruments such as NanoDrop or MySpec (microvolume spectrophotometers). A disadvantage of a NanoDrop instrument is that the sample is in direct contact with the instrument, and this typically leads to problems with mechanics, optics, and biofi lm after a few years. NanoCuvette One allows the measurement of 0.5 μL droplets of biomolecules using a conventional large- volume (3 mL)

spectrophotometer. Th e format of Cphnano‘s cuvette solution means that the optics in the UVVis instrument are not in contact with the sample and therefore last longer. Cphnano‘s cuvettes have a large dynamic measurement range, are calibrated from the factory in Farum, and they can be changed continuously. As the NanoCuvette One makes use of existing UV-Vis equipment, the purchase of new equipment is not necessary (no CAPEX). NanoCuvette One can be used to quantify chlorophyll content and the optical properties of water for aquaculture, which today is done using a fl uorometer and transmissometer.

NanoCuvette S, analyses particles in minutes

Another of Cphnano‘s core products, the NanoCuvette S, can be used for spectrophotometric quantifi cation of particle/cell size and concentration analysis. Th e NanoCuvette S can determine particles down to 50 nm, while quantifying the concentration. Th e NanoCuvette S allows for combined angle-resolved light scattering and absorbance at 190–1100 nm. Integrated into the surface is a patented photonic nanocrystal (optical fi lter) that detects light scattering so that it measures particle sizes near the photonic crystal surface. With the NanoCuvette S, particles can be quantifi ed in minutes with increased sensitivity, reliability, and reproducibility in a standard spectrophotometer without expensive specialised instruments. NanoCuvette S can be used to establish the quality of culture water by determining the size of feed particles, and can identify the level of feed uptake in recirculating aquaculture systems (RAS). Th e SpectroWorks software automatically analyses the results. SpectroWorks is the fi rst online cloud service for UV-Vis spectrum analysis that simplifi es working with spectrophotometry and calculates results. It can analyse UV-Vis spectrum like other spectroscopy software and also calculate refractive index, particle size, and concentration, which can be used to determine plastic particles contaminating the water in an RAS plant.

Links spectrophotometers and allows control with any device

All NanoCuvettes are plastic consumables with diff erent capabilities. SpectroLink, an IoT device, can enhance experimental workfl ows digitally. It connects spectrophotometers (currently VWR and Shimadzu, with more brands in the future) and allows control with any device such a tablet, laptop, or mobile telephone. Th is can be energy and time effi cient with modern device technology, allowing control from one device. SpectroLink can communicate with online software SpectroWorks allowing easy, real-time access to analysis with spectrophotometers via SpectroLink. SpectroWorks is an online data platform that automates spectral data treatment, creating insights and intelligence faster and at low cost. Th is data platform utilises more than 200 million optical simulations to create a truly digital state-of-the-art workplace for all spectral analysis, with automatic insight reporting.

Protecting water purity in north…

Another project the company is participating in is DigiBoost. Denmark’s drinking-water supply is taken entirely from groundwater, and the quality is generally good. However, over the past 35 years, one of the substantial challenges facing the Danish drinking-water supply has been pollution from toxic materials from factories, chemicals from old waste dump sites, and insecticides, pesticides, and nitrates from farming. In the period 1998–2003, the maximum allowable concentrations were exceeded in 32 of well screens in the monitoring areas, despite regulations to prevent contamination. Over recent decades, many waterworks have been closed, forced to drill deeper, or forced to buy water from neighbouring water supplies. Th erefore, it is important to monitor groundwater quality on a regular basis. However, the lack of resources, excessive cost, and lengthy analysis time limit the frequent analysis of drinking groundwater. Together with Watercare Guard and the University of Southern Denmark, the company is conducting easy, fast, and reliable real-time water monitoring at landfi lls where the state-of-the-art sensor technology and advanced cloud-based software SpectroWorks will be used to build a stationary unit that continuously monitors the water and delivers the result within a few minutes. A portable water testing station was demonstrated to quantify target toxins in the fi eld at a competitive price and sensitivity using NanoCuvette One.

Automated insight´s report from SpectroWorks™, from data from a Shimadzu UV-1800 instrument determining the protein concentration.

…and south

In the south, the company’s three-year scientifi c project, Photons and AI for Aquifer monitoring Needs: a cyber-physical system for monitoring groundwater quality (PAANEE) began in 2021 in India. Cphnano leads a consortium comprising the University of Southern Denmark, and the Indian Institute of Technology, Bombay, to develop and test a cyber-physical, AI-driven water quality monitoring system for rural communities. Water-quality monitoring in rural communities is challenging because the communities are often located far from laboratories. More than 40 of India’s rural population drink water from hand-pumped wells, yet only 7,500 of the 30 million wells in India had their water quality tested in 2015. Data from 2011 revealed that approximately 130 million people in India live in districts where at least one