1. |
- Akbas, Meltem Yesilcimen, et al.
(author)
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Improved ethanol production from cheese whey, whey powder, and sugar beet molasses by “Vitreoscilla hemoglobin expressing” Escherichia coli
- 2014
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In: Bioscience, biotechnology and biochemistry. - : Informa UK Limited. - 0916-8451 .- 1347-6947. ; 78:4, s. 687-694
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Journal article (peer-reviewed)abstract
- This work investigated the improvement of ethanol production by engineered ethanologenic Escherichia coli to express the hemoglobin from the bacterium Vitreoscilla (VHb). Ethanologenic E. coli strain FBR5 and FBR5 transformed with the VHb gene in two constructs (strains TS3 and TS4) were grown in cheese whey (CW) medium at small and large scales, at both high and low aeration, or with whey powder (WP) or sugar beet molasses hydrolysate (SBMH) media at large scale and low aeration. Culture pH, cell growth, VHb levels, and ethanol production were evaluated after 48 h. VHb expression in TS3 and TS4 enhanced their ethanol production in CW (21–419%), in WP (17–362%), or in SBMH (48–118%) media. This work extends the findings that “VHb technology” may be useful for improving the production of ethanol from waste and byproducts of various sources.
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2. |
- Balaban, Merve, et al.
(author)
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Antibiofilm effects of pomegranate peel extracts against B. cereus, B. subtilis and E. faecalis
- 2021
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In: International journal of food science & technology. - : Wiley. - 0950-5423 .- 1365-2621. ; 56:10, s. 4915-4924
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Journal article (peer-reviewed)abstract
- In this study, the antibacterial and antibiofilm properties of pomegranate (Punica granatum L.) extracts (PPLs) prepared by 10g of pomegranate peels (PPL10) and 100 mL of different solvents (ethanol, methanol, and their acid combinations, and water) were investigated as sources of bioactive compounds against food related bacteria. The antimicrobial activities of the extracts were measured by using agar well diffusion assay. The acid-treated extracts exhibited the highest antimicrobial activities (31-34 mm). The biofilm formations were assessed by using a microplate reader (570 nm) after crystal violet staining. The prevention and removal of bacterial biofilms were also evaluated by using extracts prepared by 5g of initial pomegranate peel (PPL5) with the different solvents or 200 ppm chlorine solution. All PPL5 and PPL10 extracts diluted at different ratios inhibited and removed biofilms and the highest antibiofilm effects were up to 80% by acid-treated extracts. In addition, PPL5s and PPL10s were as effective as or more effective than chlorine for the prevention of biofilms. Therefore, from an economical perspective the PPL5s could represent promising candidates as natural antibiofilm agents for food industry.
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3. |
- Balaban, Merve, et al.
(author)
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Screening for Bioactive Compound Rich Pomegranate Peel Extracts and Their Antimicrobial Activities
- 2022
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In: Johnson Matthey Technology Review. - 2056-5135. ; 66:1, s. 81-89
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Journal article (peer-reviewed)abstract
- In this work, seven different extracts from pomegranate (Punica granatum L., cv. Hicaznar) peel were prepared by using different solvents (ethanol, methanol, either alone or in combination with acid, acetone and water). The phenolics (punicalagins and ellagic acid), organic acids (citric acid and malic acid) and sugars of pomegranate peel extracts were determined. The highest amounts of punicalagins and ellagic acid were detected by ethanol-acid extract as 13.86% and 17.19% (w/v) respectively, whereas the lowest levels were obtained with acetone and water extracts. Moreover, the methanol-acid (3.19%malic acid) and ethanol-acid (1.13% citric acid) extracts contained the highest levels of organic acids. The antimicrobial activities of extracts were investigated by agar well diffusion method. Methanol-acid and ethanol-acid extracts exhibited the highest antimicrobial effects on all tested microorganisms, giving inhibition zones ranging in size from 17 to 36 mm. Although similar antimicrobial activities were observed by ethanol, methanol, and acetone extracts (up to 24 mm), the lowest antimicrobial activities were attained by water extract (0-15 mm). All extracts were generally more effective against Gram-positive bacteria: Enterococcus facealis, Bacillus subtilis, Bacillus cereus than Gram-negative ones: Escherichia coli and Enterobacter aerogenes. It was shown that extracts from pomegranate peels represent a good source of bioactive compounds.
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4. |
- Celik, Kamile Burcu, et al.
(author)
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In-situ wrapping of tin oxide nanoparticles by bacterial cellulose derived carbon nanofibers and its application as freestanding interlayer in lithium sulfide based lithium-sulfur batteries
- 2018
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 530, s. 137-145
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Journal article (peer-reviewed)abstract
- Lithium-Sulfur (Li-S) batteries are mostly known for their high energy density and cost-effectiveness. However, their intrinsic problems hinder their implementation into the marketplace. The most pronounced problems are the parasitic reactions which occur between lithium polysulfides species and lithium metal anode, the volume expansion of sulfur (80%) at the end of discharge and the safety issues which are linked with the use of lithium metal. Herein this work, two approaches are applied to prevent these effects; one approach is the use of Li2S as cathode material, instead of starting from sulfur powder, both to circumvent the volume expansion of sulfur taking place during discharge and to enable lithium-free anodes cell assembling (i.e. Si-Li2S or Sn-Li2S cell configurations). Second approach deals with the lithium anode protection by SnO2 containing freestanding pyrolyzed bacterial cellulose interlayers located between anode and cathode electrodes. Since bacterial celluloses are formed in the presence of SnO2 nanoparticles, the resulting structure enables intimate contact between carbon and SnO2 nanoparticles. By employing Li2S cathode and freestanding interlayer concurrently, 468 mAh g−1 discharge capacity is obtained at C/10 current density over 100 cycles.
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5. |
- Dursun, Burcu, et al.
(author)
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Pyrolyzed bacterial cellulose-supported SnO2 nanocomposites as high-capacity anode materials for sodium-ion batteries
- 2016
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In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:4, s. 2597-2607
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Journal article (peer-reviewed)abstract
- Room-temperature sodium-based batteries have the potential for meeting large-scale grid energy storage needs. Inspired by the advancement of the design and building of electrode materials in lithium-ion batteries, improved nano-architectured electrodes can be created for sodium-ion batteries, allowing increased electron transport kinetics and conductivities. Here, nanocomposites with 3D porous structures are reported as a high-capacity anode material for sodium-ion batteries by using an easy, low-cost and environmentally friendly synthesis of pyrolyzed bacterial celluloses (PBCs). Bacterial celluloses (BCs) produced by the Gluconacetobacterxylinus strain are pyrolyzed at 500, 750 and 1000 C, resulting 50, 130 and 110 mAh g-1 capacities over 80numbers of cycles, respectively, in the presence of the binary ethylene carbonate–propylene carbonate mixture. In order to increase the cell performances, in situated SnO2 nanoparticles with bacterial cellulose(SnO2@PBC) are produced by addition as synthesized5-nm-sized SnO2 nanoparticles into the BC growth medium together with the G. xylinus strain. Following the pyrolysis at 500 C, the SnO2@PBC composite is better able to handle the accommodation of the dramatic volume change of the incorporated SnO2nanoparticles because of the interaction of oxygen-containing moieties of bacterial cellulose nanofibrils with the SnO2 nanoparticles during cellulose production. The resulting SnO2@PBC composite presents highly stable capacity retention of around400 mAh g-1 capacities at C/10 current density over 50 numbers of cycles.
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6. |
- Rousta, Neda, et al.
(author)
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Effects of fungal based bioactive compounds on human health: Review paper
- 2023
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In: Critical reviews in food science and nutrition. - : Informa UK Limited. - 1040-8398 .- 1549-7852. ; , s. 1-24
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Research review (peer-reviewed)abstract
- Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food.
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7. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Antimicrobial Activities of Olive Oil Mill Wastewater Extracts against Selected Microorganisms
- 2023
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In: Sustainability. - 2071-1050. ; 15:10
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Journal article (peer-reviewed)abstract
- Discovering eco-friendly alternatives to synthetic chemicals has become an increasingly popular area of research. Natural products are now in the spotlight for their potential use as replacements for synthetic chemicals. To maximize the benefits of these natural products, it is important to use efficient extraction methods, especially from agroindustrial waste. Olive oil mill wastewater (OOMW) is a byproduct of the olive oil production process and is considered a pollutant; however, OOMW contains a wide range of phenolic compounds that have proven antimicrobial properties. This study investigates the extraction of these compounds from OOMW, with the aim of determining their potential antimicrobial activities against several bacterial strains and fungi, including Bacillus spizizenii, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aerogenes, Streptococcus uberis, Enterococcus faecalis, and Candida albicans. The OOMW extracts (OEs) were prepared by using three different solvents: ethyl acetate, ethanol, and methanol. The highest total phenolic contents (4.03 g, GAE/L) and the strongest antibacterial activity were obtained with methanol extraction. All OEs showed no antifungal activity against C. albicans. OEs, particularly methanol extracts of OOMW, can be used as bioactive substances in various industries as nutraceuticals and food ingredients, respectively.
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8. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(author)
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Bioethanol production from whey powder by immobilized E. coli expressing Vitreoscilla hemoglobin : optimization of sugar concentration and inoculum size
- 2021
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In: Biofuels. - : Informa UK Limited. - 1759-7269 .- 1759-7277. ; 12:9, s. 1103-1108
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Journal article (peer-reviewed)abstract
- A combined Vitreoscilla hemoglobin/immobilization system was evaluated for ethanol production using whey powder as a carbon source and ethanologenic E. coli strain FBR5 and its Vitreoscilla hemoglobin (VHb) expressing derivative strain, TS3. The effects of varying the inoculation concentration (5, 10, 20 or 30%) of alginate beads containing cells of either strain, and the lactose levels (8–15%) of whey powder media (WP8-WP15), were studied. Ethanol production was enhanced in strain TS3 compared to strain FBR5 for all combinations of inoculation size and medium lactose concentration. This enhancement increased from 41% to 83% with an 8–15% increase in lactose concentration. The maximum amount of ethanol, 4.64% (v/v) with 99% fermentation efficiency, was produced after growth for 72 h by immobilized strain TS3, using 10% bead inoculation and medium containing 8% lactose.
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9. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Biorecovering of phenolic-rich compounds from food industry wastes
- 2022
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Conference paper (peer-reviewed)abstract
- In food industry, abundant fruit/vegetable byproducts (peel, seed, etc.) have been generated and released into the environment. These wastes can be considered as a largely available, low-cost source of value-added compounds. Among these, phenolic compounds are well-known for their beneficial effects on human health. Effective extraction methodologies are required for recovery of these phenolic compounds from agri-food wastes. These extracts can be used used as natural antimicrobials in pharmacology or disinfectants in food processing plants. In this work, pomegranate peel extracts were prepared by using different solvents to obtain high amount of phenolic-rich compounds. The pomegranate peel extracts were also tested against some important food pathogens to determine their antimicrobial and antibiofilm activities. Pomegranate peel extracts having high amount of phenolic compounds had higher antimicrobial and antibiofilm activities. As a result, phenolic-rich bioactive compounds can be recovered from food industry wastes and used as natural antimicrobial and antibiofilm agents. Thus, food industry wastes, especially fruit wastes, can be integrated into the extraction process and use in food, pharmacology, cosmetic and medicine industries.
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10. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(author)
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Combining co-culturing of Paenibacillus strains and Vitreoscilla hemoglobin expression as a strategy to improve biodesulfurization
- 2021
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In: Letters in Applied Microbiology. - : Oxford University Press (OUP). - 0266-8254 .- 1472-765X. ; 72:4, s. 484-494
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Journal article (peer-reviewed)abstract
- Enhancement of the desulfurization activities of Paenibacillus strains 32O-W and 32O-Y were investigated using dibenzothiophene (DBT) and DBT sulfone (DBTS) as sources of sulphur in growth experiments. Strains 32O-W, 32O-Y and their co-culture (32O-W plus 32O-Y), and Vitreoscilla hemoglobin (VHb) expressing recombinant strain 32O-Yvgb and its co-culture with strain 32O-W were grown at varying concentrations (0.1–2 mmol l-1) of DBT or DBTS for 96 h, and desulfurization measured by production of 2-hydroxybiphenyl (2-HBP) and disappearance of DBT or DBTS. Of the four cultures grown with DBT as sulphur source, the best growth occurred for the 32O-Yvgb plus 32OW co-culture at 0.1 and 0.5 mmol l-1 DBT. Although the presence of vgb provided no consistent advantage regarding growth on DBTS, strain 32O-W, as predicted by previous work, was shown to contain a partial 4S desulfurization pathway allowing it to metabolize this 4S pathway intermediate.
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11. |
- Sar, Taner, 1989-, et al.
(author)
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Effective ethanol production from whey powder through immobilizedE. coliexpressingVitreoscillahemoglobin
- 2016
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In: Bioengineered. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 8:2, s. 171-181
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Journal article (peer-reviewed)abstract
- Ethanol production from whey powder was investigated by using free as well as alginate immobilized E. coli and E. coli expressing Vitreoscilla hemoglobin (VHb) in both shake flask and fermenter cultures. Media with varying levels of whey (lactose contents of 3%, 5%, 8% or 15%) and yeast extract (0.3% or 0.5%) were evaluated with fermentation times of 48–96 h. Immobilization and VHb expression resulted in higher ethanol production with all media; the increases ranged from 2% to 89% for immobilization and from 2% to 182% for VHb expression. It was determined that growth medium containing 8% lactose with 0.5% yeast extract yielded the highest ethanol production for free or immobilized strains, with or without VHb expression, in both shake flask and fermenter cultures. Immobilization with alginate was found to be a promising process for ethanol production by VHb-expressing ethanologenic E. coli.
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12. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Improvement in desulfurization of dibenzothiophene and dibenzothiophene sulfone by Paenibacillus strains using immobilization or nanoparticle coating
- 2022
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In: Journal of Applied Microbiology. - : Oxford University Press (OUP). - 1364-5072 .- 1365-2672. ; 133:2, s. 1040-1051
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Journal article (peer-reviewed)abstract
- AimsBiodesulfurization of fossil fuels is a promising technology for deep desulfurization. Previously, we have shown that Paenibacillus strains 32O-W and 32O-Y can desulfurize dibenzothiophene (DBT) and DBT sulfone (DBTS) effectively. In this work, improvements in DBT and DBTS desulfurization by these strains were investigated through immobilization and nanoparticle coating of cells.Methods and ResultsPaenibacillus strains 32O-W and 32O-Y immobilized in alginate gel beads or coated with Fe3O4 magnetite nanoparticles were grown at various concentrations (0.1–2 mmol l−1) of DBT or DBTS for 96 h. The production of 2-hydroxybiphenyl (2-HBP) from the 4S pathway biotransformation of DBT or DBTS was measured. The highest amounts of 2-HBP production occurred at concentrations of 0.1 and 0.5 mmol l−1. Compared to planktonic cultures maximum 2-HBP production increased by 54% for DBT and 90% for DBTS desulfurization with immobilized strains, and 44% for DBT and 66% for DBTS desulfurization by nanoparticle-coated strains.ConclusionsNanoparticle-coated and immobilized cells may be of use in efforts to increase the efficiency of biodesulfurization.Significance and Impact of the StudyAlginate immobilization or nanoparticle coating of bacterial cells may be useful approaches for the enhancement of biodesulfurization for eventual use on an industrial scale.
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13. |
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14. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Integration of olive oil industry wastewaters into biorefinery
- 2023
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Conference paper (peer-reviewed)abstract
- While olive oil is an important food product in the Mediterranean Sea Basin, olive oil mill wastewater (OOMW) and olive pomace, which are by-products of olive oil, are released in excessive quantities. OMWW is an important source of environmental pollutants due to its slightly acidic pH, high phenol content and high chemical oxygen demand (COD). To overcome this problem, it was aimed to investigate the potential use of OOMW as an alternative substrate for protein rich biomass and bacterial cellulose production by filamentous fungi and acetic acid bacterium, respectively, in this study. Additionally, extracts of OOMW against selected microorganisms were examined to determine their use for industrial applications. The finding results indicated that OOMW needs nitrogen supplementation for microbial production processes. On the other hand, extracts of OOMW showed significant antibacterial activities with high phenolic contents. Overall, OOMW can be integrated into biorefinery with both microbial production and extraction processes and the resulting products will contribute to the food and cosmetic industries.
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15. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(author)
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Investigation of growth properties of Paenibacillus strains in the presence of 2-HBP
- 2021
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Conference paper (peer-reviewed)abstract
- Crude oil and fossil fuels contain sulphur compounds. Consumption of these compounds could cause acid rain and environmental pollution. Dibenzothiophene (DBT) is considered as model compound for investigation of fossil fuel desulphurization. This compound is converted to 2-HBP following bio-desulphurization (BDS) by 4S pathway. This work aimed to investigate bacterial growth properties in the presence of 2-HBP which is a final product of DBT desulphurization. For this, two Paenibacillus strains (32 O-W and 32 O-Y) were incubated in 2-HBP (to give the final concentrations at 0.05, 0.1, and 0.2 mM) containing growth media. Although the OD600 value of the 32 O-W strain was low at all 2-HBP concentrations, the 32 O-Y strain could survive, and its OD levels were 3–4 fold higher than 32 O-W strain. As a result, it can be interpreted that the final products of DBT metabolism did not too toxic, and thus bio-desulfurization can be successfully completed by Paenibacillus strains. Acknowledgments: This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, 118Y416).
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16. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Novel Perspectives on Food-Based Natural Antimicrobials: A Review of Recent Findings Published since 2020
- 2023
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In: Microorganisms. - 2076-2607. ; 11:9
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Research review (peer-reviewed)abstract
- Various fruit and vegetable wastes, particularly peels, seeds, pulp, and unprocessed residues from the food industry, are abundant sources of antioxidants and essential antimicrobial agents. These valuable bioactive compounds recovered from the food industry have a great application in food, agriculture, medicine, and pharmacology. Food-derived natural antimicrobials offer advantages such as diminishing microbial loads and prolonging the shelf life of food products particularly prone to microbial spoilage. They not only enrich the foods with antioxidants but also help prevent microbial contamination, thereby prolonging their shelf life. Similarly, incorporating these natural antimicrobials into food packaging products extends the shelf life of meat products. Moreover, in agricultural practices, these natural antimicrobials act as eco-friendly pesticides, eliminating phytopathogenic microbes responsible for causing plant diseases. In medicine and pharmacology, they are being explored as potential therapeutic agents. This review article is based on current studies conducted in the last four years, evaluating the effectiveness of food-based natural antimicrobials in food, agriculture, medicine, and pharmacology.
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17. |
- Sar, Taner, Postdoctoral Researcher, 1989-, et al.
(author)
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Potential use of olive oil mill wastewater for bacterial cellulose production
- 2022
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In: Bioengineered. - : NLM (Medline). - 2165-5979 .- 2165-5987. ; 13:3, s. 7659-7669
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Journal article (peer-reviewed)abstract
- In this study, olive oil mill wastewater (OOMW), an important waste in the Mediterranean basin, was evaluated to produce bacterial cellulose (BC). For this purpose, the effects of different ratios of OOMW fractions (25-100%) and some additional nutrients (yeast extract, peptone and Hestrin-Schramm medium (HS) components) on BC productions were investigated. Unsupplemented OOMW medium (75% and 100%) yielded as much as BC obtained in HS medium (0.65 g/L), while enrichment of OOMW medium (%100) with yeast extract (5 g/L) and peptone (5 g/L) increased the amount of BC by 5.5 times, reaching to 5.33 g/L. In addition, produced BCs were characterized by FT-IR, TGA, XRD and SEM analyses. BC from OOMW medium (100% OOMW with supplementation) has a high thermal decomposition temperature (316.8°C), whereas it has lower crystallinity index (57%). According to the FT-IR analysis, it was observed that the components of OOMW might be absorbed by BCs. Thus, higher yield productions of BCs from OOMW media compared to BC obtained from HS medium indicate that olive oil industry wastes can be integrated into BC production for industrial applications.
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18. |
- Sar, Taner, Postdoctor, 1989-, et al.
(author)
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Repeated batch fermentation of immobilized E. coli expressing Vitreoscilla hemoglobin for long-term use
- 2017
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In: Bioengineered. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 8:5, s. 651-660
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Journal article (peer-reviewed)abstract
- This study describes an efficient and reusable process for ethanol production from medium containing whey powder, using alginate immobilized ethanologenic E. coli strains either expressing (TS3) or not expressing (FBR5) Vitreoscilla hemoglobin. Reuseabilities of the FBR5 and TS3 strains were investigated regarding their ethanol production capacities over the course of 15 successive 96-h batch fermentations. The ethanol production was fairly stable over the entire duration of the experiment, with strain TS3 maintaining a substantial advantage over strain FBR5. Storage of both strains in 2 different solutions for up to 60 d resulted in only a modest loss of ethanol production, with strain TS3 consistently outperforming strain FBR5 by a substantial amount. Strains stored for 15 or 30 d maintained their abilities to produce ethanol without dimunition over the course of 8 successive batch fermentations; again strain TS3 maintained a substantial advantage over strain FBR5 throughout the entire experiment. Thus, immobilization is a useful strategy to maintain the advantage in ethanol productivity afforded by expression of Vitreoscilla hemoglobin over long periods of time and large numbers of repeated batch fermentations, including, as in this case, using media with food processing wastes as the carbon source.
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19. |
- Unlu, Aise, et al.
(author)
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Biofilm formation by Staphylococcus aureus strains and their control by selected phytochemicals
- 2018
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In: International Journal of Dairy Technology. - : Wiley. - 1364-727X .- 1471-0307. ; 71:3, s. 637-646
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Journal article (peer-reviewed)abstract
- Biofilm formation by 30 Staphylococcus aureus dairy isolates and their control by phytochemicals were investigated. The majority of strains were biofilm positive by phenotypic analysis. The nuc and icaA genes were present in 30 and 27 strains, respectively. In addition, 13 strains were positive for all nuc, clfA, fnbA and icaA genes. The antimicrobial and antibiofilm activities of citral, cinnamaldehyde, eugenol, farnesol, limonene and terpinen-4-ol were also evaluated for seven strains. It was shown that the use of farnesol, cinnamaldehyde or terpinen-4-ol at a concentration of 2 mg/mL could be at least 80% effective on S. aureus strains and their biofilms.
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