Abstract |
In the present work, the growth of a photosynthetic microorganism strain of the
genus Chlorella, was investigated by using as substrate dairy waste from the primary
stage of production. The objective of this work was to investigate the ability of this
particular strain in bioremediation applications regarding liquid dairy waste. The target
was dual, biomass production and simultaneous decrease of various environmental
parameters from the waste-waters. It was observed that microalgae had the ability to
grow in dairy waste-waters. However, a limiting factor for cell growth appeared to be
the lack of some nutrients, which were either absent in the waste or present in unassimilable form by microbial metabolism. Thus, the enrichment of the waste-waters
with nutrients (phosphates, ammonium and trace elements) was also investigated. It
was shown that enrichment with nutrients enhanced the production of biomass by the
cells. The mixotrophic culture of the cells, with a content of 50% in primary pasteurized
whey and with the addition of trace elements led to the highest values of cell
concentration and biomass.
Chlorella cells were cultured under both heterotrophic and mixotrophic
conditions, using as a medium cheese-dairy wastewaters from the primary stage of
production. The cultures were allowed to grow for a period of one week. After this
period several important parameters were evaluated. These included the evaluation of
the content of photosynthetic pigments, maximum photosynthetic efficiency and
biomass production.
The main conclusion of the present research was that the conditions that favored
the growth were directly dependent on the concentration and type of whey, the addition
of nutrients and the type of culture (mixotrophic or heterotrophic). It was shown that
photosynthetic microorganisms can adapt to different experimental conditions that
cause stress, with the ability of simultaneous increase of their biomass. These
characteristics provide a perspective for the development of several application
regarding food and energy production as well as waste-water management.
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