‘MidSouth’, a relatively low maintenance interspecific hybrid bunch grape currently grown in South Mississippi, has low sugar and high acid levels for red wine use. Two studies, conducted at the Mississippi State University McNeill Research Unit in 2020 and 2021, determined the effects of pruning timing, leaf removal, and shoot thinning on ‘MidSouth’ development and fruit and wine quality. Treatments in the first study included early versus normal pruning timing, both with and without leaf removal, and treatments in the second study included leaf removal, shoot thinning, and control vines. Cluster temperatures, leaf chlorophyll, berries per cluster, berry and cluster weights, crop yield, Ravaz index, total soluble solids, titratable acidity, juice pH, monomeric anthocyanin pigment, and total phenolic content data were collected. It was determined that ‘MidSouth’ fruit quality can be altered through canopy manipulation, but not enough of a desired effect was achieved for these practices to be recommended.

This work seeks to compare various Acetone-Butanol-Ethanol (ABE) fermentation extraction chemicals on an economic and environmental basis. The chemicals considered are: decane, a decane/oleyl alcohol blend, decanol, a decanol/oleyl alcohol blend, 2-ethyl-hexanol, hexanol, mesitylene, and oleyl alcohol. To facilitate comparison a pure-distillation base case was also considered. The aforementioned extractants are a mix of both toxic and non-toxic extractants. Non-toxic extractants can be used directly in fermentation reactors, improving overall fermentation yield by removal of toxic butanol. The extractants were modelled in Aspen Plus V8.8 and separation trains were designed to take advantage of extractant properties. The separation section of the plant was then integrated with upstream and downstream units to determine the Minimum Butanol Selling Prices (MBSP) for second generation extractive ABE fermentation. Upstream processes include biomass (switchgrass) solids processing, biomass pre-treatment/saccharification and fermentation while downstream processes include utility generation and wastewater treatment. The cost of CO2 equivalent emissions avoided (CCA) was used as a metric to compare environmental impact of each process as compared to gasoline. The economic best and environmental best extractant is shown to be 2-ethyl-hexanol with a MBSP of $1.58/L and a CCA of $471.57/tonne CO2 equivalent emissions avoided. Wastewater treatment, which is often ignored in other works, was found to makeup over 30% of total installed capital cost for all extractants. / Thesis / Master of Applied Science (MASc)

Mutacin 1140, a class 1 bacteriocin, is produced by Streptococcus mutans and belongs to the type A lantibiotic family. Experiments were done to optimize production of mutacin 1140 in minimal media enabling a more cost efficient downstream purification method. The development of a small volume fermentation method enabled a rapid screen of several variables in a standard shaking incubator. This method provided a fast approach for determining components that promote mutacin 1140 production in minimal media broth. Lactose was determined to be the optimal carbon source for mutacin 1140 production. High concentrations of CaCl2 (0.3% w/v) and MgSO4 (0.77% w/v) promoted an increase in mutacin 1140 production, while ZnCl2 and FeCl3 appeared to impair production. Optimization of mutacin 1140 production in minimal media resulted in more than a 100old increase in production compared to the base medium used to begin our optimizations. The yield has been estimated by RP-HPLC to be 10 mg/L.

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