Browsing by Author "Kelleci, K."

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Determination of the Anticarcinogenic Activity of 5-Hydroxymethyl-2-furfural Produced from Grape Must Under in Vitro Conditions
(Turkish Chemical Society, 2023) Kelleci, K.; Gölebatmaz, E.
Every year, millions of tons of food and beverage waste are thrown away unused around the world. The carbohydrates found in food waste create a raw material potential for the production of high value-added products that are used in energy, feed and pharmacology. One of these products, 5-Hydroxymethyl-2-furfural (5-HMF), is a by-product of simple dehydration of carbohydrates. It finds wide use in the field of pharmacy due to its anticancer, antifungal and antimicrobial activities. Many studies have stated that the sugar source with the highest conversion rate in 5-HMF production is fructose. For this reason, in this study, it was aimed to realize the production of 5-HMF in autoclave sterilization carried out under high temperature and pressure using grape must waste, which is known to have high fructose content, and determine the anticarcinogenic activity and cytotoxicity of the produced 5-HMF under in vitro conditions. In this study, it was determined that the medium containing DMSO increased the sugar conversion percentage, 5-HMF efficiency and selectivity in the waste grape must more than the medium containing only water. In the production of 5-HMF, the conversion of sugar in the medium saturated with salt, and the efficiency and selectivity of 5-HMF were determined as 97.04%, 68.61% and 70.82%, respectively, when DMSO organic solvent was used. In addition, it has been determined that 5-HMF produced from waste grape must has a toxic effect on both healthy cells and cancer cells and has anticancer properties. © 2023, Turkish Chemical Society. All rights reserved.
Valorization of Beet-Processing Sugar Factory By-Products for In-Situ Gluconic Acid Production by Using Aspergillus Niger Fermentation
(Springer, 2023) Kelleci, K.; Altundoǧan, H.S.; Tanyildizi, M.Ş.
The beet-processing sugar industry is facing a severe crisis in some countries due to high production costs. This situation also negatively affects the beet producers. To increase the profit of beet-processing sugar plants, it is considered that the evaluation of by-products such as molasses, beet-pulp, and carbonation cake to obtain valuable organic acids could be commercially available. In this study, gluconic acid production by fermentation with A. niger has been investigated by using by-products obtained from beet-processing sugar plant. The experimental conditions have been optimized for gluconic acid production by submerged, semi solid-state, and solid-state fermentation routes by using Response Surface Methodology (RSM). Gluconic acid production efficiencies under the optimized conditions for submerged, semi solid-state, and solid-state fermentations were calculated as 0.258, 0.354, and 0.262 g gluconic acid per g of absolute solid substrate, respectively. It has been determined that citric and oxalic acid together with gluconic acid could be produced at the significant levels for all three fermentation routes. It has been observed that obtaining oxalic and citric acid along with gluconic acid using A. niger depend strongly on pH. Gluconic acid was produced at near-neutral pH, whereas oxalic (pH ~ 4–4.5) and citric (pH < 2) acids were obtained at lower pH. In conclusion, in-situ production of gluconic and important organic acids can be realized by using beet-processing sugar plant by-products and some waste energy with simple fermentation techniques. Under the present circumstances, this approach is the most convenient way to survive the crisis that uses appropriate fungal/bacterial cultures. © 2022, The Author(s), under exclusive licence to Society for Sugar Research & Promotion.