Browsing by Author "Esim, Nevzat"

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Direct Conversion of Waste Loquat Kernels to Pigments Using Monascus Purpureus Atcc16365 with Proteolytic and Amylolytic Activity
(Springer Heidelberg, 2021) Arslan, Nazli Pinar; Yazici, Aysenur; Komesli, Senba; Esim, Nevzat; Ortucu, Serkan
Kernels of loquat (Eriobotrya japonica L.) fruits are rich in protein and starch contents; however, they have no significant application in world. This study was performed to produce pigments from Monascus purpureus ATCC16365 using loquat kernel powder (LKP) as a fermentation substrate and investigate the effect of four mineral salts (CaCl2, KH2PO4, MgSO4, and FeSO4) on pigment production in LKP-based medium. During the experiments, LKP was not subjected to any chemical or enzymatic hydrolysis, and it was tested directly as a substrate in shaking flask and fermenter cultures. It was found that addition of CaCl2 alone decreased red pigment production but did not cause an important change in synthesis of yellow and orange pigments. Supplementation of KH2PO4, MgSO4, or FeSO4 alone decreased the production of yellow pigment but increased the production of red pigments. When three salts (1.0 g/L KH2PO4, 0.3 g/L MgSO4, and 0.03 g/L FeSO4) were added together to the LKP-based medium, more productions of enzymes (protease and amylase) and red pigments were achieved. When experiments were performed in optimized medium (LKP and three mineral salts), maximum concentrations of red, orange, and yellow pigments were determined as 292, 193, and 171 AU/L in flask culture but 327, 241, and 204 AU/L in fermenter culture, respectively. Amylase and protease activities were 93.4 and 52.3 U/L in flask culture but 93.8 and 52.8 U/L in fermenter culture, respectively. This is the first report on the use of LKP as a substrate in production of enzymes and pigments from M. purpureus.
Efficient Production of L-Lactic Acid from Chicken Feather Protein Hydrolysate and Sugar Beet Molasses by the Newly Isolated Rhizopus Oryzae Ts-61
(Elsevier, 2012) Taskin, Mesut; Esim, Nevzat; Ortucu, Serkan
The aim of this study was to investigate production of L-lactic acid from molasses and chicken feather protein hydrolysate (CFP) by the newly isolated Rhizopus oryzae TS-61. R. oryzae TS-61 was capable of utilizing molasses sucrose and CFP as carbon and nitrogen sources, respectively. In contrast to yeast extract and ammonium sulfate, CFP had potential not only to prevent excessive pH changes and foaming but also to provide smaller uniform pellet formation in during fermentation. Thanks to these properties, it was concluded that CFP might have resulted in higher L-lactic acid production than the other two nitrogen sources (yeast extract and ammonium sulfate). At the end of 42-h optimal cultivation period, the highest (38.5 g/L) and lowest (28.8 g/L) concentrations of L-lactic acid were obtained with CFP and ammonium sulfate, respectively. This is the first report on use of waste chicken feather as a lactic acid production substrate. In addition, a new R. oryzae strain, being capable of using molasses sucrose as carbon source in order to produce L-lactic acid, was isolated. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Enhancement of Invertase Production by Aspergillus Niger Oz-3 Using Low-Intensity Static Magnetic Fields
(Taylor & Francis Inc, 2013) Taskin, Mesut; Esim, Nevzat; Genisel, Mucip; Ortucu, Serkan; Hasenekoglu, Ismet; Canli, Ozden; Erdal, Serkan
The aim of this study is to investigate the effect of low-intensity static magnetic fields (SMFs) on invertase activity and growth on different newly identified molds. The most positive effect of SMFs on invertase activity and growth was observed for Aspergillus niger OZ-3. The submerged production of invertase was performed with the spores obtained at the different exposure times (120, 144, 168, and 196hr) and magnetic field intensities (0.45, 3, 5, 7, and 9 mT). The normal magnetic field of the laboratory was assayed as 0.45mT (control). Optimization of magnetic field intensity and exposure time significantly increased biomass production and invertase activity compared to 0.45 mT. The maximum invertase activity (51.14U/mL) and biomass concentration (4.36g/L) were achieved with the spores obtained at the 144hr exposure time and 5mT magnetic field intensity. The effect of low-intensity static magnetic fields (SMFs) on invertase activities of molds was investigated for the first time in the present study. As an additional contribution, a new hyper-invertase-producing mold strain was isolated. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.
Natural Metabolites with Antioxidant Activity from Micro-And Macro-Algae
(Elsevier, 2024) Esim, Nevzat; Dawar, Pranav; Arslan, Nazli Pinar; Orak, Tugba; Doymus, Meryem; Azad, Fakhrul; Taskin, Mesut
In humans, excess accumulation of reactive oxygen species (ROS) produces oxidative stress, resulting in cell and tissue damage, and eventually, leading to variety of diseases. Excess ROS can be eliminated, and its detrimental repercussions avoided by combining endogenous and exogenous antioxidants. A plant-based diet and dietary supplements are a major source of exogenous antioxidants; however, fungi, bacteria, lichens, insects, and algae (macroalgae and microalgae) are also deemed as potential sources for exogenous antioxidants. For example, algal biomass and extracts can be directly consumed or their purified metabolites can be used as antioxidants. Furthermore, some exogenous antioxidant molecules can be synthesized only by algae but not by other organisms. Antioxidant molecules derived from algae, include a variety of polysaccharides, pigments (carotenoids, phycobiliproteins etc), mycosporins-like amino acids, phytosterols, phenolic compounds (phenolic acids, bromophenols, phlorotannins, flavonoids etc), fatty acids, and alkaloids. They exhibit potent antioxidant activities confirmed by in vitro scavenging assays (DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide and nitric oxide radicals) and/or by reducing or chelating metal ions. In addition, algal-derived antioxidants have also been tested in in vivo models and have demonstrated high antioxidant activities achieved by upregulation of antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and inhibition of lipid peroxidation. This review study focuses on the antioxidant potential of different natural compounds obtained from different algal groups (macroalgae, eukaryotic microalgae and prokaryotic microalgae). This review is based primarily on research and review articles published in the last five years (2019-2023) and written in English.