Browsing by Author "Taskin, Mesut"

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Chicken Feather Peptone: A New Alternative Nitrogen Source for Pigment Production by Monascus Purpureus
(Elsevier Science Bv, 2018) Orak, Tugba; Caglar, Ozge; Ortucu, Serkan; Ozkan, Hakan; Taskin, Mesut
Peptones are accepted as one of the most favourable nitrogen sources supporting pigment synthesis in Monascus purpureus. The present study was performed to test the feasibility of chicken feather peptone (CFP) as nitrogen source for pigment production from M. purpureus ATCC16365. CFP was compared with fish peptone (FP) and protease peptone (PP) in order to elucidate its effectiveness on pigment production. CFP was prepared from waste feathers using hydrolysis (KOH) and neutralization (H2SO4) methods. The protein content of CFP was determined as 67.2 g/100 g. Optimal concentrations of CFP and glucose for pigment production were determined as 3 and 20 g/L, respectively. A medium pH of 5.5 and an incubation period of 7-days were found to be more favourable for pigment production. In CFP, PP and FP media, yellow pigment absorbances were 2.819, 2.870 and 2.831, red pigment absorbances were 2.709, 2.304 and 2.748, and orange pigment absorbances were 2.643, 2.132 and 2.743, respectively. Sugar consumption and mycelia growth showed the similar trends in CFP, FP and PP media. This study indicates that the peptone from chicken feathers may be a good nutritional substrate for pigment production from M. purpureus.
Development of a Hybrid Photodetector Device Between Pyruvic Acid (CH3COCOOH) and Silicon
(IOP Publishing Ltd, 2021) Orhan, Zeynep; Yildirim, Fatma; Taskin, Mesut; Incekara, Umit; Aydogan, S.
The authors report on the fabrication of a pyruvic acid (Pyr)/p-Si heterojunction photodetector and analyses of electro-optical behavior of the device. First, Pyr film was coated on p-Si by spin coating method. The morphology and elemental structure of this film were determined by scanning electron microscopy and energy dispersive x-ray analysis, respectively. In order to analyze the device's performance, the current-voltage (I-V) measurements were performed in the dark. The device was a rectification ratio of about 10(5) in the dark, and photodetector device parameters such as responsivity, on/off ratio and specific detectivity were analyzed in light intensity-dependent I-V measurements. Measurements depending on the light intensity were carried out between 15 and 30 mW cm(-2), at 5 mW cm(-2) intervals. The capacitance-voltage (C-V) and conductance-voltage (G-V) measurements carried out in the dark were analyzed at low and high frequencies in addition to the dielectric properties of the Pyr/p-Si heterojunction. Experimental results showed that the Pyr/p-Si device can be effectively applied to optical sensors and imaging devices.
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.
Evaluation of Waste Loquat Kernels as Substrate for Lipid Production by Rhodotorula Glutinis SO28
(Springer, 2017) Ortucu, Serkan; Yazici, Aysenur; Taskin, Mesut; Cebi, Kadir
This study was performed to produce lipids from the isolated oleaginous yeast Rhodotorula glutinis SO28 using loquat kernel extract (LKE) as substrate. LKE was prepared using acid hydrolysis and alkaline neutralization steps. Lipid production was performed in shaking flaks culture. Even if LKE was used as a sole source of nutritional substances, it could support cell growth and lipid synthesis in the yeast. Additional carbon, nitrogen and phosphorus sources were found to significantly alter the lipid accumulation potential of the yeast. Optimal concentrations of additional carbon (glucose) and nitrogen (ammonium sulphate) sources for lipid accumulation were determined as 15 and 0.5 g/L, respectively. On the other hand, all the concentrations of additional phosphorus source were found to significantly reduce the lipid accumulation. Optimal incubation time was determined as 132 h. Under the optimized culture conditions, the lipid concentration and lipid content of the yeast were determined as 7.82 g/L and 62 %, respectively. Fatty acid methyl ester analysis exhibited that this yeast strain could produce high proportions of C16:0 and C18 fatty acids, which are ideal for biodiesel production. This is the first report on the use of waste loquat kernels as substrate for microbial lipid production.
Improving Light-Sensing Behavior of Cu/N-Si Photodiode with Human Serum Albumin: Microelectronic and Dielectric Characterization
(Elsevier GmbH, 2021) Orhan, Zeynep; Yilmaz, Mehmet; Aydogan, Sakir; Taskin, Mesut; Incekara, Umit
This research was mainly focused on the investigation of the effect of Human Serum Albumin (HSA) on the electrical features of Cu/n-Si device. To do this, HSA layer was grown as an interfacial layer between Cu and n-Si to create Cu/HSA/n-Si device. To investigate the performance of the obtained device architecture in optoelectronic applications, the electrical and photoresponse properties of the device were evaluated by current-voltage measurements at different light power intensities. The results show that as well as the device showed a good rectification characteristic in the dark, it also showed that it exhibits a good photodiode property at different light intensities. Besides, main diode parameters such as ideality factor, effective barrier height, and series resistance were evaluated by thermionic emission theory and Cheung approximation. Obtained results from both calculation methods revealed that diode parameters highly depend on the light power intensity. This variation in the diode parameter is explained in detail taking electron-hole formation in the HSA and n-Si into consideration. Besides, the capacitive properties of the device were investigated with capacitance-voltage measurements in the frequency range of 200 and 1000 kHz and it was observed that the device exhibits capacitive properties in this range. Furthermore, main dielectric parameters such as dielectric constant, dielectric loss, and loss tangent were also evaluated by using impedance spectroscopy in the different frequency range and results showed that all-dielectric parameters highly depend on frequency. All obtained results have been discussed in detail.
In Vitro Evaluation of Probiotic and Antioxidant Potential of Lacticaseibacillus Paracasei Ed25
(Springer, 2024) Dasdemir, Elanur; Arslan, Nazli P.; Ortucu, Serkan; Aykutoglu, Gurkan; Ozkan, Hakan; Adiguzel, Ahmet; Taskin, Mesut
This study aimed to assess the in vitro probiotic and antioxidant potential of lactic acid bacteria (LAB) isolated from different white cheeses, also known as "Beyaz Peynir" in Turkey. A total of 58 bacterial strains were isolated from 11 different white cheeses obtained from small-scale dairies. According to some preselection criteria (having the distinctive features of LAB, exhibiting non-haemolytic property, and resisting the simulated gastrointestinal conditions such as low pH, pepsin, pancreatin and bile salt tolerance), four (ED13, ED20, ED25 and ED36) out of 58 isolates were selected for the subsequent experiments. Among the four isolates, ED25 exhibited the maximum lactase production and cholesterol removal potential, the highest biological activity (antimicrobial and antioxidant activity) and the lowest antibiotic resistance. In addition, the second highest B12-producing capacity were measured for ED25. The isolate ED25 was found to possess antimicrobial effectiveness against all tested microorganisms (S. aureus, E. coli, S. Typhimurium, L. monocytogenes and C. albicans) according to the agar well diffusion method. In vitro antioxidant activity assay demonstrated that the culture supernatant of the ED25 had the ability to scavenge DPPH (49%), ABTS (37%), OH center dot (51%) and O-2(center dot-) (38%) radicals. According to the sequences analysis of the 16 S rRNA gene, the isolate ED25 was identified as Lacticaseibacillus paracasei (GenBank accesion number: OP036674.1). Due to strong biological activities, L. paracasei ED25 may be used as a probiotic agent against gastrointestinal disorders, infections and oxidative stress-mediated diseases.
Invertase Production and Molasses Decolourization by Cold-Adapted Filamentous Fungus Cladosporium Herbarum Er-25 in Non-Sterile Molasses Medium
(Elsevier, 2016) Taskin, Mesut; Ortucu, Serkan; Unver, Yagmur; Tasar, Ozden Canli; Ozdemir, Mustafa; Kaymak, Haluk Caglar
This study was undertaken to remove the coloring compounds of molasses as well as produce extracellular (exo) invertase in sterile and non-sterile molasses medium by using cold-adapted filamentous fungus Cladosporium herbarum ER-25. It was determined that a combination of low culture pH (5.5), temperature (20 degrees C) and high molasses concentration (6%) could completely prevent undesired bacterial contamination during the cultivation of C. herbarum ER-25. Under the optimized non-sterile culture conditions, the maximum invertase activity (36.1 U/mL) was attained after 72 h. On the other hand, the fungus could remove toxical dark brown pigments (melanoidins) in non-sterilized molasses medium through biodegradation and bioadsorption mechanisms. A color removal rate of 64.8% in non-sterile medium could be achieved at the end of 144-h cultivation period. It was found that lac case and manganese peroxidase were responsible for biodegradation. No ligninase activity was detected for the fungus during the cultivation. Maximum laccase (4.6 U/mL) and manganese peroxidase (3.5 U/mL) activities could be reached after 120 h. Higher invertase activity and color removal rate were achieved in non-sterilized medium compared to sterilized one. This is the first report on invertase production from cold-adapted microorganisms under non-sterile culture conditions. As an additional contribution, use of cold-adapted fungi for molasses decolourization was investigated for the first time in the present study. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
L-Lactic Acid Production by Rhizopus Oryzae Mbg-10 Using Starch-Rich Waste Loquat Kernels as Substrate
(Wiley-V C H Verlag GmbH, 2013) Taskin, Mesut; Ortucu, Serkan; Unver, Yagmur; Arslan, Nazli Pinar; Algur, Omer Faruk; Saghafian, Amir
The objective of this work was to perform production of L-lactic acid from starch-rich waste loquat kernels by newly isolated Rhizopus oryzae MBG-10 fungus. Loquat kernel flour (LKF) was used as substrate (mainly as carbon source). The most favorable conditions for L-lactic acid production were LKF concentration of 80g/L, CaCO3 concentration of 20g/L, ammonium sulfate concentration of 3g/L and incubation time of 108h. Under these conditions, L-lactic acid and biomass concentrations were 45.4 and 8.2g/L, respectively, and -amylase activity was 81.6U/mL. No significant pH changes were observed in the medium thanks to the buffering capacity of LKF. L-lactic acid could be produced in a single-stage from starch-rich LKF without prior saccharification by the fungus with high amylolytic enzyme activity. This is the first report on use of waste loquat kernels as a lactic acid production substrate.
Lipase Production with Free and Immobilized Cells of Cold-Adapted Yeast Rhodotorula Glutinis HL25
(Elsevier Science BV, 2016) Taskin, Mesut; Ucar, Muhammed Hanifi; Unver, Yagmur; Kara, Ayse Aydan; Ozdemir, Mustafa; Ortucu, Serkan
This study was undertaken to produce the lipase by free and immobilized cells of cold-adapted yeast Rhodotorula glutinis HL25 using waste frying oils as substrate. The optimization of culture parameters was performed using traditional one-factor-at-a-time protocol. The temperature 20 degrees C and initial pH 6.0 were optimal for lipase production by both free and immobilized cells. An inoculum size of 40 mL/L for free cells and beads number of 150 g/L for immobilized cells were optimal for lipase production. Optimal waste frying oil concentration and incubation time were 30 mL/L and 84 h for free cells but 40 mL/L and 72 h for immobilized cells, respectively. The maximum increases for free and immobilized cells were achieved at the Triton X-100 concentrations of 5 and 7.5 mL/L, respectively. The maximum lipase activities were determined as 54.4 and 75.2 U/L for free and immobilized cells, respectively. Immobilized cells could be used in five successive reaction cycles without any loss in the maximum activity. Immobilized cells could retained about 70% of their maximum activity by the end of the cycle 10. This is the first attempt on lipase production potential of a cold-adapted strain of the yeast R. glutinis. Furthermore, lipase production using immobilized cells of cold-adapted yeasts was investigated for the first time. (C) 2016 Elsevier Ltd. All rights reserved.
Lipid Production from Sugar Beet Molasses Under Non-Aseptic Culture Conditions Using the Oleaginous Yeast Rhodotorula Glutinis Tr29
(Pergamon-Elsevier Science Ltd, 2016) Taskin, Mesut; Ortucu, Serkan; Aydogan, Mehmet Nuri; Arslan, Nazli Pinar
In this study the lipid production potential of the isolated yeast Rhodotorula glutinis TR29 in molasses medium under non-aseptic culture conditions was investigated. Different molasses concentrations and initial pH values were tested to make R. glutinis TR29 cells more dominant population in the medium, thereby preventing undesired microbial contaminants. Contamination could be prevented by selecting the high molasses concentration (20%) and low initial pH (5.0). When these parameters were kept constant, the optimum temperature, additional nitrogen source concentration and incubation time for the lipid production were found to be 25 degrees C, 4 g/L and 168 h, respectively. Under these culture conditions, the cell mass and lipid concentration were determined as 16.2 and 10.5 g/L, respectively. The lipid content was determined as 64.8%. The main cellular fatty acids of the yeast were oleic (63.5%), politic acid (15.4%), stearic acid (9.1%) and palmiteloic acid (7.2%). The yeast lipids seems to be a promising feedstock for biodiesel production due to a high content of C16 and C18 fatty acids. To our best knowledge, this is the first work on lipid production by yeasts in non-sterile molasses medium. (C) 2016 Elsevier Ltd. All rights reserved.
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.
Natural-Based Antibiofilm and Antimicrobial Peptides from Micro-Organisms
(Bentham Science Publ Ltd, 2018) Yazici, Aysenur; Ortucu, Serkan; Taskin, Mesut; Marinelli, Lisa
As the resistance to antimicrobial molecules increases among bacteria, the need for new antimicrobial molecules increases. Antimicrobial peptides (AMP), which may be a new generation of antibiotic candidates, are important in this respect. AMPs are small, cationic and amphipathic peptide sequences. In eukaryotes, they are synthesized as a part of the immune system. Substantially, AMPs are discovered in all kingdoms of life such as bacteria, fungi and protozoa. Approximately 3,000 AMPs have been reported in the literature. However, most of these AMPs have been synthesized through chemical synthesis. Nature has a huge source of microorganisms, and in the literature, there is a tendency to increase every year the number of bacteria and fungus-derived AMPs thanks to their biotechnological importance. The exploration of AMP and antibiofilm peptide (ABP) producer microorganisms brings with it a lot of challenges experimentally. In this review study, we want to highlight the importance and challenge of these natural peptides derived from microorganisms. We will also propose a new explanation for ABPs.
A New Enzyme for Biodiesel Production and Food Applications: Lipase of Bacillus Megaterium F25 Isolated from an Aquatic Insect Rhantus Suturalis
(Wiley, 2024) Karaman, Fatima; Incekara, Umit; Arslan, Nazli Pinar; Albayrak, Seyda; Ortucu, Serkan; Taskin, Mesut
This study aimed to isolate, purify, and characterize a lipase from the gut symbiont Bacillus megaterium F25 (GenBank accession: MF597792) of the aquatic insect Rhantus suturalis, with a focus on its potential applications in biodiesel and food industries. Under optimized culture conditions, B. megaterium F25 could produce 583 U/L of lipase in shaking flask culture. The purified lipase (PL) exhibited a specific activity with 113.89 U/mg, and its molecular weight was determined as 34 kDa. The activity of PL was enhanced by methanol, ethanol, Tween-80, Triton X-100, Ca2+, and Mg2+, while beta-mercaptoethanol, EDTA, SDS, Fe2+, Mn2+, and Cu2+ were inhibitory. PL showed optimal activity and stability at neutral and slightly acidic pHs, as well as in a temperature range of 20 degrees C-30 degrees C. PL displayed strong hydrolytic activity toward plant oils and animal fats, indicating its potency for both the food industry and the remediation of oil-contaminated environments. When tested as a catalyst, PL provided biodiesel production with a transesterification yield of 86.8% under optimized conditions (36 h reaction time, 4 mL enzyme solution, 30 degrees C, pH 7.0, and waste cooking oil:methanol ratio of 10 mL/40 mL). This is the first report on the lipase-producing potential of gut microbial symbionts of aquatic insects. Furthermore, B. megaterium lipase was tested for the first time as a biocatalyst for biodiesel production.
Nitric Oxide: A Novel Inducer for Enhancement of Microbial Lipase Production
(Springer, 2016) Taskin, Mesut; Unver, Yagmur; Yildiz, Melike; Ortucu, Serkan; Askin, Hakan
The purpose of this study was to elucidate whether exogenous nitric oxide (NO) has a potential beneficial effect on lipase production capacity of some microorganisms. Sodium nitroprusside (SNP) was used as an exogenous NO donor in production medium. In comparison with the control (0 nM SNP), SNP concentrations from 10 to 100 nM induced lipase production in mesophilic bacterium Bacillus subtilis and cold-adapted yeast Yarrowia lipolytica. Especially, the maximum lipase activities for Y. lipolytica (81.2 U/L) and B. subtilis (74.5 U/L) were attained at 30 and 50 nM SNP concentrations, respectively. When compared to the control, the optimal SNP concentrations resulted in about 5.14 and 2.27-fold increases in lipase activities of B. subtilis and Y. lipolytica, respectively. Besides, it was found that the optimal SNP concentrations provided shorter incubation periods for lipase production. Conversely, no significant positive effect of exogenous NO on lipase production was determined for thermophilic bacterium Geobacillus stearothermophilus. This study showed for the first time that exogenous NO could be used as an inducer in the production of microbial lipases.
Photo-Sensor Characteristics of Tannic Acid (C76H52O46)/N-Si Hybrid Bio-Photodiode for Visible and UV Lights Detection
(Elsevier Sci Ltd, 2022) Yildirim, Fatma; Orhan, Zeynep; Taskin, Mesut; Incekara, Umit; Biber, Mehmet; Aydogan, S.
We present the electo-optical characterization of tannic acid (TA)/n-Si heterojunction for visible and UV lights (365 nm and 395 nm). The TA was deposited on n-Si by spin coating. The morphological and structural analyses of TA film were carried out by Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray (EDX) analyses, respectively. The electro-optical performance of the TA/n-Si bio-photodiode were investigated by I-V measurements for 10 mW/cm(2), 15 mW/cm(2), 20 mW/cm(2) and 30 mW/cm(2) visible light intensities in addition to UV light. Light-dependent the responsivity, ON/OFF ratio, detectivity, shunt resistance and series resistance were calculated. Maximum values of responsivity, detectivity and ON/OFF ratio were determined as 11.9 mA/W (-1.5 V), 3.2 x 109 Jones (at-0.42 V) and 194 (30 mW/cm2) (AM 1.5 G), at-2 V respectively. Whereas, they were determined to be 0.1 A/W, 4 x 109 Jones and 14977, respectively for UV light. Furthermore, the dielectric properties of the TA/n-Si heterostructure also were investigated from the dark Capacitance/Conductance-Voltage measurements. It was seen that both real and imaginary parts of the dielectric constants was frequency dependent. Experimental results show that the TA/n-Si device with a high rectification ratio of 2263 is a potential candidate for detecting visible and UV lights.
Protease Production by Free and Immobilized Cells of the Cold-Adapted Yeast Cryptococcus victoriae CA-8
(Taylor & Francis Ltd, 2015) Unver, Yagmur; Yildiz, Melike; Taskin, Mesut; Arslan, Nazli Pinar; Ortucu, Serkan
The present study was performed to produce the protease using free and immobilized cells of locally isolated cold-adapted psychrotolerant yeast Cryptococcus victoriae CA-8. Cell immobilization was performed using sodium alginate as entrapping agent. The best conditions for enzyme production by both free and immobilized cells of the yeast were temperature of 15 degrees C and initial pH of 8.0. The optimal incubation times were 72 and 96 h for immobilized and free cells, respectively. Immobilized cells were reused in 3 successive reaction cycles without any loss in the maximum protease activity. Little decreases in the protease activity were observed in 4 and 5 cycles. Under the optimized conditions, the maximum enzyme activities were determined as 12.1 and 13.5 U/mL for free and immobilized cells, respectively. This is a first attempt on cold-active alkaline protease production by free and/or immobilized cells of yeasts. Besides, the protease activity of the yeast C. victoriae CA-8 was investigated for the first time in the present study.
A Review on Bacteria-Derived Antioxidant Metabolites: Their Production, Purification, Characterization, Potential Applications, and Limitations
(Pharmaceutical Society Korea, 2025) Arslan, Nazli Pinar; Azad, Fakhrul; Orak, Tugba; Budak-Savas, Aysenur; Ortucu, Serkan; Dawar, Pranav; Taskin, Mesut
Antioxidants are organic molecules that scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS), thereby maintaining cellular redox balance in living organisms. The human body synthesizes endogenous antioxidants, whereas humans obtain exogenous antioxidants from other organisms such as plants, animals, fungi, and bacteria. This review primarily focuses on the antioxidant potential of natural metabolites and extracts from five major bacterial phyla, including the well-studied Actinobacteria and Cyanobacteria, as well as less-studied Bacteroides, Firmicutes, and Proteobacteria. The literature survey revealed that the metabolites and the extracts with antioxidant activity can be obtained from bacterial cells and their culture supernatants. The metabolites with antioxidant activity include pigments, phycobiliproteins, polysaccharides, mycosporins-like amino acids, peptides, phenolic compounds, and alkaloids. Both metabolites and extracts demonstrate in vitro antioxidant capacity through radical-scavenging, metal-reducing, and metal-chelating activity assays. In in vivo models, they can scavenge ROS and RNS directly and/or indirectly eliminate them by enhancing the activities of antioxidant enzymes, such as catalase, superoxide dismutase, and glutathione peroxidase. Due to their antioxidant activities, they may find applications in the cosmetic industry as anti-aging agents for the skin and in medicine as drugs or supplements for combating oxidative stress-related disorders, such as neurodegenerative diseases and diabetes. The literature survey also elucidated that some metabolites and extracts with antioxidant activity also exhibited strong antimicrobial properties. Therefore, we consider that they may have future applications in the treatment of infectious diseases, the preparation of pathogen-free healthy foods, and the extension of food shelf life.
Screening and Characterization of a Novel Antibiofilm Polypeptide Derived from Filamentous Fungi
(Elsevier, 2021) Yazici, Aysenur; Ortucu, Serkan; Taskin, Mesut
In the present study, 120 fungal isolates were locally isolated from soil and selected according to their ability to antimicrobial activity. Then, selected isolates were tested for their ability to prevent biofilm formation and only one isolate (A01) showed an antibiofilm effect. The isolate A01 identified as Aspergillus tubingensis by sequencing of the 18S ITS region and a segment of beta-tubulin gene. Then, 5 fractions were prepared from the culture filtrate of A. tubingensis A01 using the ultrafiltration technique to find active polypeptide fraction. The experiments revealed that one of them had an antibiofilm activity. The MALDI-TOF/MS analyses demonstrated that this polypeptide composed of 92 amino acids and had a molecular mass of 10,087 Da. The sequence alignment showed homology with hypothetical protein (OJI81679.1). The gene coding for this polypeptide consisting of 279 nucleotides, herein we called astucin, was cloned and sequenced from A. tubingensis A01 to confirm results. The MIC of the purified polypeptide was 32 m/L and 128 mu g/mL and the MBIC was 2 and 8 mu g/mL against Staphylococcus aureus and MRSA, respectively. The results demonstrated that the antimicrobial and antibiofilm activity of astucin, together with its lack of cytotoxicity, makes it an alternative for application in medicine. Significance: Antibiotic resistance is a global problem and the emergence of antibiotic resistant bacteria reduce the effect the current treatment approaches. In this context, antimicrobial peptides stand out as potentional agents to combat bacterial infection especially, biofilm related infections. Importantly, this study have greatly considered our understanding for fungal derived antibiofilm polypeptides. In this study, traditional selection method combined with crystal violet assay is used to investigate antibiofilm polypeptides. We identified antibiofilm polypeptides purified from A. tubingensis A01. This protein shows antimicrobial and antibiofilm activity against S. aureus.
Sheep Wool Protein Hydrolysate: A New Peptone Source for Microorganisms
(Wiley, 2016) Taskin, Mesut; Unver, Yagmur; Firat, Abdulhadi; Ortucu, Serkan; Yildiz, Melike
BACKGROUND: Peptones are one of the most expensive components of microbial culture media. The present study was performed to produce microbial peptone from sheep wool using a new chemical process. RESULTS: Wool peptone (WP) was found to have high protein (67.8 g per 100 g) and ash (29.2 g per 100 g) contents. Glutamic acid was the most abundant amino acid inWP with a content of 8175 mg per 100 g). Wool peptone (WP) also had a high content (5042 mg per 100 g) of cystine, a sulphur-containing amino acid. Optimal concentration of WP was determined as 5 g L-1 for the fungi and 6 g L-1 for the bacteria. Staphylococcus aureus showed very poor growth performance in WP medium. Growth performances of Saccharomyces cerevisiae, Bacillus subtilis and Penicillium chrysogenum were at moderate levels in WP medium. The best growth performance for Aspergillus niger was observed in WP medium with a biomass production of 8.17 g L-1. Second best growth performance for Escherichia coli was achieved with WP among the tested peptones. CONCLUSION: Wool peptone (WP) was shown to be a good growth substrate, especially for A. niger and E. coli. This is the first investigation on use of wool as peptone source or substrate for microorganisms. (C) 2016 Society of Chemical Industry