Bacteria are in key role for successful recirculating aquaculture
farming

Date:
September 9, 2020
Source:
University of Jyva"skyla" - Jyva"skyla"n yliopisto
Summary:
Aquaculture is one of the fastest growing food production sectors
globally. Due to continuous growth, ecologically, economically and
socially sustainable sites for aquaculture are already in use, which
has caused a need for new fish farming techniques. Recirculating
aquaculture systems, technology that recycles and saves water,
has expanded in recent years. The operation and management of
bioreactors has been one of the biggest issues.



FULL STORY ========================================================================== Aquaculture is one of the fastest growing food production sectors
globally. Due to continuous growth, ecologically, economically and
socially sustainable sites for aquaculture are already in use, which has
caused a need for new fish farming techniques. Recirculating aquaculture systems, technology that recycles and saves water, has expanded in
recent years. The technology has not yet achieved economic viability,
mainly due to high investment and operating costs.

In addition, the operation and management of bioreactors has been one
of the biggest issues, which microbiological processes were studied by
M.Sc. Jani Pulkkinen in his dissertation.


========================================================================== Bioreactors utilize bacteria in the water purification process. In
bioreactors, toxic ammonia excreted by fish is microbially converted to
more harmless nitrate in the nitrification process.

"Although bioreactors are designed for the decomposition of nitrogen
compounds, the main functions of bacteria in bioreactors were the
decomposition of carbohydrates, amino acids and fats. The impact of
bioreactors as a whole on water quality is thus much more diverse
than previously thought. A diverse and stable bacterial community can
maintain good water quality, not only in terms of nitrogen compounds,
but also in organic matter," Jani Pulkkinen says.

Different types of bioreactors can trap solids from water or affect the
gas balance, but different bioreactors also have different nitrification efficiencies, i.e. how fast ammonia can be converted to nitrate.

"The sizing and selection of bioreactor type should be done taking
into account the characteristics of the entire water treatment system,"
says Pulkkinen.

The biological and mechanical solids removal capacity of bioreactors can compensate the properties of the rest of the water treatment system. By optimizing the entire water treatment system, the best possible water
quality can be maintained for the well-being and growth of the fish,
which enables cost-effective and environmentally friendly aquaculture.

The dissertation consisted of four publications using modern molecular microbiology methods. All studies were conducted in the experimental recirculating aquaculture facilities of the Natural Resources Institute
Finland (Luke) Laukaa fish farm. The dissertation has been funded by
Luke, the European Union and the Ministry of Agriculture and Forestry
from the European Maritime and Fisheries Fund.

The doctoral dissertation has been published in the JYU Dissertations
series, number 242, University of Jyva"skyla", Jyva"skyla" 2020, ISSN 2489-9003, ISBN 978-951-39-8197-6.


========================================================================== Story Source: Materials provided by University_of_Jyva"skyla"_-_Jyva"skyla"n_yliopisto. Note: Content may
be edited for style and length.


==========================================================================


Link to news story: https://www.sciencedaily.com/releases/2020/09/200909100259.htm

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