Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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1995 - 199912010 - 20172

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Author: search.filters.author.Göksungur, Yekta

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  • Article
    Citation - WoS: 33
    Citation - Scopus: 34
    Exploitation of Agricultural Wastes and By-Products for Production of Aureobasidium Pullulans Y-2311 Xylanase: Screening, Bioprocess Optimization and Scale Up
    (Springer Verlag, 2017) Yeğin, Sırma; Büyükkileci, Ali Oğuz; Sargın, Sayıt; Göksungur, Yekta
    The potential of several agricultural wastes and by-products (wheat bran, oat bran, corn cob, brewer’s spent grain, malt sprout, artichoke stem, sugar beet pulp, olive seed, cotton stalk and hazelnut skin) was examined as the substrate for xylanase production by Aureobasidium pullulans Y-2311-1. Based on the screening studies, wheat bran was selected as the best substrate for further optimization studies. The effects of initial medium pH, temperature and incubation time on xylanase production in shake flask system were optimized by response surface methodology (RSM). The optimum levels of the process variables defined by the model (initial medium pH, 4.24; temperature, 30.27 °C; and incubation time 126.67 h) resulted in production of 85.19 U/ml xylanase. Taking the RSM optimized parameters in shake-flask scale into consideration; xylanase production was scaled up to bioreactor system with a working volume of 1.5 l. The peak of enzyme production was achieved after 126 h incubation that has previously been determined by RSM studies at shake flask level. Furthermore, the optimum levels of agitation and aeration in bioreactor system was found as 200 rpm and 1.5 vvm. Maximum enzyme production was close to 85 kU/l which could be translated into a productivity of 0.68 kU/l/h. No previous work considered the statistical optimization of xylanase production by A. pullulans on wheat bran and scale up of the bioprocess to a bioreactor system
  • Article
    Citation - WoS: 72
    Citation - Scopus: 83
    Aspartic Proteinases From Mucor Spp. in Cheese Manufacturing
    (Springer Verlag, 2011) Yeğin, Sırma; Fernandez-Lahore, Marcelo; Jose Gama Salgado, Antonio; Güvenç, Ulgar; Göksungur, Yekta; Tarı, Canan
    Filamentous fungi belonging to the order of Mucorales are well known as producers of aspartic proteinases depicting milk-clotting activity. The biosynthesis level, the biochemical characteristics, and the technological properties of the resulting proteinases are affected by the producer strain and the mode of cultivation. While the milk-clotting enzymes produced by the Rhizomucor spp. have been extensively studied in the past, much less is known on the properties and potential applications of the aspartic proteinases obtained for Mucor spp. Indeed, several Mucor spp. strains have been reported as a potential source of milk-clotting enzymes having unique technological properties. Both submerged fermentation and solid substrate cultivation are proven alternatives for the production of Mucor spp. aspartic proteinases. This review provides an overview on the bioprocessing routes to obtain large amounts of these enzymes, on their structural characteristics as related to their functional properties, and on their industrial applications with focus on cheese manufacturing.
  • Article
    Adsorption Equilibrium and Dynamics of Lactase/Cm-sephadex System
    (Kluwer Academic Publishers, 1995) Harsa, Hayriye Şebnem; Göksungur, Yekta; Güvenç, Ulgar
    Partitioning behaviour and adsorption isotherms of lactase/CM-Sephadex system at equilibrium were investigated together with the adsorption kinetics in this study. Maximum adsorption was obtained at the pH values between 5.5–6.0. Adsorption isotherm was a close fit to the Langmuir model.