Browsing by Author "McMurtry, Sarah K."

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    Potential of the microalgae chlorella sorokiniana for carbon capture from winery fermentations and wastewater bioremediation
    (2022-03) McMurtry, Sarah K.; Rossouw, Debra; Bauer, Florian; Naidoo-Blassoples, Rene K.; Stellenbosch University. Faculty of Agrisciences. Dept. of Viticulture and Oenology.
    With rises in global greenhouse gases, efforts to reduce emissions have become increasingly urgent. Carbon dioxide (CO2), one of the major greenhouse gases, is a by-product of wine fermentation. The CO2 generated during this process is in a more concentrated form than CO2 derived from most industrial processes, and in principle represents an ideal source to support photosynthetic processes. The development of biological carbon capture systems may therefore allow wine producers to reduce their carbon footprint, contributing to the aim of a carbon neutral winery. Winemaking also produces vast amounts of low-quality wastewater. Currently available wastewater treatments are either costly or have various disadvantages. Consequently, the use of industrial microorganisms including microalgae for wastewater bioremediation has gained increasing interest. Microalgae can grow in, and bioremediate, numerous sources of wastewater, while producing potentially valuable biomass using CO2 as a carbon source. Coupling carbon capture from wine fermentations with the bioremediation of winery wastewater therefore shows great potential. Similar processes have already been studied in other industries such as the carpet mill industry, livestock industry and some food industries, but there is only very limited data for wine-related applications. Winery wastewater certainly presents a particular challenge because of its seasonality and rapidly changing nature. This inconsistent nature of the wastewater reduces microalgae growth and leads to inefficient carbon capture and biomass production. To alleviate this problem, previous work in our laboratory has investigated co-cultures of winery wastewater-isolated strains of the yeast Saccharomyces cerevisiae and the microalgae Chlorella sorokiniana. Such co-cultures are indeed considered more resilient than single species systems. These strains were furthermore co-evolved in order to strengthen co-culture growth. The purpose of this work was to understand and optimise this system to improve microalgae carbon capture and wastewater bioremediation. The experimental work focused on optimising growth conditions for carbon capture in a laboratory, small-scale synthetic winery environment, as well as on monitoring microalgae and yeast growth in winery wastewater. The data suggest that the system investigated here is able to generate microalgae biomass using sustainable methods, and relevant insights regarding the ability of C. sorokiniana to grow in, and to bioremediate, winery wastewater were generated. Further optimisation is however required to maintain microalgae and yeast growth for longer periods and generate additional microalgae biomass.
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    Potential of the microalgae chlorella sorokiniana for carbon capture from winery fermentations and wastewater bioremediation
    (Stellenbosch : Stellenbosch University, 2022-03) McMurtry, Sarah K.; Rossouw, Debra; Bauer, Florian; Naidoo-Blassoples, Rene K.; Stellenbosch University. Faculty of Agrisciences. Dept. of Viticulture and Oenology.
    ENGLISH ABSTRACT: With rises in global greenhouse gases, efforts to reduce emissions have become increasingly urgent. Carbon dioxide (CO2), one of the major greenhouse gases, is a by-product of wine fermentation. The CO2 generated during this process is in a more concentrated form than CO2 derived from most industrial processes, and in principle represents an ideal source to support photosynthetic processes. The development of biological carbon capture systems may therefore allow wine producers to reduce their carbon footprint, contributing to the aim of a carbon neutral winery. Winemaking also produces vast amounts of low-quality wastewater. Currently available wastewater treatments are either costly or have various disadvantages. Consequently, the use of industrial microorganisms including microalgae for wastewater bioremediation has gained increasing interest. Microalgae can grow in, and bioremediate, numerous sources of wastewater, while producing potentially valuable biomass using CO2 as a carbon source. Coupling carbon capture from wine fermentations with the bioremediation of winery wastewater therefore shows great potential. Similar processes have already been studied in other industries such as the carpet mill industry, livestock industry and some food industries, but there is only very limited data for wine-related applications. Winery wastewater certainly presents a particular challenge because of its seasonality and rapidly changing nature. This inconsistent nature of the wastewater reduces microalgae growth and leads to inefficient carbon capture and biomass production. To alleviate this problem, previous work in our laboratory has investigated co-cultures of winery wastewater-isolated strains of the yeast Saccharomyces cerevisiae and the microalgae Chlorella sorokiniana. Such co-cultures are indeed considered more resilient than single species systems. These strains were furthermore co-evolved in order to strengthen co-culture growth. The purpose of this work was to understand and optimise this system to improve microalgae carbon capture and wastewater bioremediation. The experimental work focused on optimising growth conditions for carbon capture in a laboratory, small-scale synthetic winery environment, as well as on monitoring microalgae and yeast growth in winery wastewater. The data suggest that the system investigated here is able to generate microalgae biomass using sustainable methods, and relevant insights regarding the ability of C. sorokiniana to grow in, and to bioremediate, winery wastewater were generated. Further optimisation is however required to maintain microalgae and yeast growth for longer periods and generate additional microalgae biomass.