Browsing by Subject "wastewater"

PURPOSE AND GOALS Microalgae are unicellular eukaryotic organisms capable of photosynthesis. They harvest sunlight and efficiently take up carbon dioxide and nutrients such as nitrogen and phosphorus from their environment and use them for their growth. Due to these properties, their rapid growth and ability to survive in a variety of environments, microalgae have potential in biotechnological applications that promote nutrient recovery and recycling, water purification and the carbon neutral production of biochemicals and possibly biofuels. The purpose of this study was to investigate the suitability of a side stream water originating from the production of baker’s yeast (yeastwater) for the cultivation of a species of microalga called Euglena gracilis. The study aimed to determine the capacity of this water to support growth and protein production of E. gracilis as well as the capacity of E. gracilis to remove nutrients from the water. The effect of filtration of the water on these parameters was also studied. Yeastwater contains an organic molecule called betaine in relatively high concentrations. Betaine has previously been shown to boost the production of the important vitamin cobalamin in bacteria. The study aimed to determine the effect of betaine on the growth of E. gracilis and on the production of cobalamin in the algal-bacterial symbiosis. METHODS E. gracilis was cultured in laboratory scale photobioreactors. Its growth, protein production and nutrient uptake capacity was determined. Baker’s yeast production side stream water diluted with MQ-water was used as the growth medium either in filtered or unfiltered form. A control treatment was prepared where no microalgal inoculate was added to the photobioreactor. The same microalga was also grown in a synthetic nutrient medium with and without betaine. The uptake of betaine and biomass concentrations of cobalamin were determined. For the determination of microalgal growth, dry weight determination and flow cytometry analysis were used. Protein production was determined on the basis of total nitrogen concentration in the biomass. Spectrophotometric measuring kits were used for the determination of nutrient concentrations. Liquid chromatography techniques were used for the determination of betaine and cobalamin concentrations. RESULTS Significant microalgal growth was observed in filtered yeastwater, while growth in unfiltered yeastwater was very low. Nitrogen removal was higher in presence of E. gracilis compared to the control treatment. Protein production in yeastwater was comparable to that of microalgae grown in synthetic medium. E. gracilis grew much better in the synthetic media supplemented with betaine than without the addition. Betaine enrichment had no effect on cobalamin production. Cobalamin was produced in unfiltered yeastwater both with and without the presence of E. gracilis. CONCLUSIONS Unfiltered yeastwater does not support growth of E. gracilis possibly due to its high turbidity. Filtered yeastwater, on the other hand can support the production of E. gracilis biomass. E. gracilis can be used to reduce nitrogen concentrations in yeastwater. Yeastwater can support cobalamin production by bacteria, but this phenomenon did not benefit from the presence of the microalga. The effect of betaine on microalgal growth warrants further study to determine whether it is related to the accumulation of intracellular nutrients, storage compounds or to some other phenomenon. Yeastwater is a promising nutrient feedstock for microalgal biomass production. However, the role of filtration and possibility of using other methods for turbidity reduction needs to be further studied.

The emerging crisis of antimicrobial resistance is especially worrisome in low-income countries that lack controlled antibiotic policy and have poor infrastructure. Inadequate hygiene practices combined with ability of microbes to quickly evolve and adapt to changes rise the concern of resistance of infectious pathogens to many first-line antimicrobial drugs. Moreover, wastewaters that are widely used as irrigation water in urban gardening in sub-Saharan Africa, can function as vehicle for the dissemination of bacteria that carry antimicrobial resistance genes into the surrounding environment. In this study, eight anthropogenically impacted water samples were collected from Burkina Faso and Mali and differences in their microbial communities were evaluated by 16S rRNA gene sequencing. Also, the presence of antimicrobial resistance genes was examined with SmartChip qPCR. The bacterial host range of blaNDM, blaCTX-M, blaOXA and qacE∆1 was profiled using a novel culture- independent technique, Emulsion, Paired Isolation and Concatenation PCR (epicPCR). The presence of 202 genes associated with antimicrobial resistance were detected with SmartChip qPCR array analysis, including carbapenemase genes that can transfer horizontally. Worryingly, sixteen taxonomical units, including possible human pathogens Acinetobacter, Klebsiella, Escherichia and Pseudomonas, were found to carry all the four genes investigated with epicPCR. The most abundant genus Arcobacter along with Dechloromonas, Methylotenera, MM1 and Methylophilus were new discoveries as blaNDM hosts. Furthermore, a considerable number of blaOXA and clinical class 1 integron marker qacE∆1 gene hosts were discovered in every sample. Lastly, putative events of horizontal gene transfer in two WWTP samples were observed. Broad host range of blaOXA and qacE∆1 genes suggests a heavy antimicrobial resistance genes burden in West Africa and the results support the theory that environmental bacteria can function as resistance gene reservoirs. These results show occurrence of horizontally transferrable blaNDM and blaCTX-M genes in pathogens especially in hospital wastewater, and a threat of their spread into the environment and to the community. However, to decipher their role in the infectious disease burden in Africa, more research is needed.