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Anaerobic digestion (AD) of walnut shells (WS) results in only a limited biomethane yield because of their high fibre content, which ultimately represents an essentially nonbiodegradable lignocellulosic biomass. In the present study, thermal (i.e. 50-250 °C), alkaline (i.e. 1-5% w/w NaOH) and combined alkaline-thermal (i.e. 4% w/w NaOH + 150 °C thermal) pretreatment methods have been applied to increase the anaerobic biodegradation of WS. The highest biomethane yields of 159.9 ± 6.8 mL CH4.g VS-1 and 169.8 ± 6.8 mL CH4.g VS-1 were achieved after pretreatment at both 250 °C and with 4% NaOH. After combined NaOH-thermal pretreatments, the AD process showed the largest total VFA concentration (i.e. 1280.1 mg Hac L-1) but a relatively high lag phase (i.e. 3.90 days) compared to thermal and NaOH pretreatments alone, from which the highest biomethane yield (i.e. 192.4 ± 8.2 mL CH4.g VS-1 ) was achieved at the end of the AD process. The highest biomethane yield from the combined NaOH-thermal pretreated WS was corroborated by the corresponding highest SCOD/TCOD ratio (i.e. 0.37 ± 0.02) and the highest lignocellulosic fibre removal (i.e. 41.1 ± 2.7% cellulose, 35.6 ± 1.8% hemicellulose, and 58.7 ± 3.2% lignin). The cumulative biomethane yields were further simulated via a modified Gompertz model. This study provides a promising strategy in the sense that the biomethane yield of WS containing large amounts of lignin can be significantly increased via thermal, NaOH, and combined NaOH-thermal pretreatment methods.

Coronaviruses are causative agents of the last three epidemics/pandemic; Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) and the last one Severe Acute Respiratory Syndrome-Cov-2 (SARS-CoV-2). Although meta-analysis of treatment studies against these three coronaviruses found no clear benefit of any spesific regimen, currently, remdesivir and favipiravir are promising potential therapies for SARS-CoV-2. On the other hand, since natural products have always played a crucial role in drug discovery and development process against various diseases, many groups in the world, are now trying to find new or repurposed natural or naturally originated drugs against viruses and coronaviruses. Secondary metabolites of the plants, particularly alkaloids and terpenoids have been exhibited strong antimicrobial and anticancer activities besides synthetic drugs and other natural compounds (nucleosides and nucleotides and bacterial and fungi originated ones). The first isolated secondary metabolites have been converted into important drugs since 1800’s such as morphine, codeine, cocaine, and quinine have alkaloid skeleton as well as some of the recent anticancer drugs vinblastine, vincristine, taxol, etc. This review includes the last two decades of publications about natural alkaloids rather than their plant extracts which showed some promising results against coronaviruses. Marine organisms are also another rich source to discover new lead drugs, however they were excluded in the present review article.

WOS: 000520732400001 In this study, anaerobic co-digestion of apple pulp (AP) with high carbon content and chicken manure (CM) with high nitrogen content was evaluated with regard to sulphuric acid pretreatment conditions in the concentration range of 1%-6% v/v. The best mixing ratio of CM:AP was determined as 3:1 w/w under untreated conditions for which the methane yield was 255.88 +/- 11.55 mL/g VS (volatile solid). Sulphuric acid pretreatments were applied to this mixture ratio. The highest methane yield after pretreatment was 466.01 +/- 10.85 mL/g VS in the reactor, where the sulphuric acid pretreatment concentration was 3.0% v/v. Control of acid pretreatment results were achieved by analysis of lignocellulosic degradation and increase in soluble chemical oxygen demand. The highest cellulose, hemicellulose and lignin degradation after pretreatment were 27.5% +/- 1.4%, 35.9% +/- 2.9% and 14% +/- 1.5% w/w, respectively. The cumulative methane yields (CMY) were analysed by the modified logistic model, modified Bertalanffy model (MBM), modified Gompertz model (MGM) and modified Holling model (MHM). The MBM and MGM were found to fit the experimental data better than other models. The MHM has not previously been applied to CMY. In addition to the kinetic studies, new critical points for CMYs were identified in the logistics model (lm). The importance and critical properties of these points with regard to CMY are introduced. The differences and superior properties of these critical points compared to other modelling methods are discussed.

Bu çalışmada elma posası (EP), portakal posası (PP) ve tavuk gübresi (TG) karışım oranlarından anaerobik çalışma koşulları altında biyogaz üretimi gerçekleştirilmiştir. Çalışma sıcaklığı (dış yüzey sıcaklığı) bütün deneyler için 40 0C olarak seçilmiştir. Kütlece birtakım karışım oranları oluşturulmuş olup optimum kütlece karışım oranı EP:PP:TG ; 1:2:3 olarak belirlenmiştir. Ortalama anaerobik süreç 86-90 gün sürmüştür. En yüksek biyogaz üretimi 215 ml biyogaz/g UKolarak bulunmuştur.Daha sonra bu karışım oranlarına 100 0C ve 120 0C de termal önişlem uygulanmıştır. Uygulanan termal önişlem sonuçlarına göre 100 0C uygulanan önişleme göre % 157,2 ve 120 0C’ de uygulanan önişleme göre ise % 158,6 daha fazla biyogaz üretimi olduğu bulunmuştur.

Biomethane production by anaerobic digestion has an important role in disposal of waste and renewable energy recovery. By conducting the appropriate experimental analysis to determine Turkey's bovine manure-based biomethane potential (BMBP), this study presents a valuation of the spatial distribution of the biomethane potential by year and province, including forecasting for such to 2030. In this context, the BMBP for each year between 2002 and 2019 was determined for the total installed power potential (TIPP) and biomethane potential per capita. The BMBPs for each province for the last seven years (2013–2019) in Turkey were illustrated by using geographical information system software. As of 2019, the biomethane-based TIPP of 17.87 million bovine manures was 1389 MW, which corresponded to approximately 1.53% of the total installed power. To express this in different units, the total BMBP for the country was 1.757 billion m3 in 2002, but by comparison reached 3.163 billion m3 in 2019. In addition, an artificial neural network (ANN) model with a number of independent variables gross domestic product (GDP) per capita, GDP agricultural, gross national product, human and bovine population was developed to forecast the BMBP to 2030. It was determined that the ANN-forecasted biomethane potential in 2030 will increase by approximately 50% more than the biomethane potential in 2019. Thus, this study will be an important resource in comparing the past and future values of BMBP in developing countries such as Turkey, estimating them with ANN and predicting renewable energy gain and animal manure disposal for countries.

In this study, anaerobic digestion of sewage sludge with different ultrasonic pretreatment (USp) conditions was investigated. USp were applied at a constant ultrasonic density of 0.5 W/mL with sonication times of 0–240 min. While the methane yield of the untreated (control) reactor was 170.1 ± 4.7 mL/g volatile solids (VS), the highest methane yield was 266.1 ± 7.5 mL/g VS in the reactor where sonication was applied for 120 min. Actual specific energy input (SEA)/nominal specific energy input (SEN) ratios after USps were measured for pretreatment yield. These values varied between 77.0 and 14.87% according to different sonication times. Sonication times of more than 30 min did not significantly increase the methane yield due to possible reflocculation. After the USps, various cumulative methane yields were predicted via the modified Gompertz Model, modified Logistic Model, and Artificial Neural Network (ANN) model (Scenario 1); of these the ANN model made predictions that were closest to the experimental data. In the other part of the study, ANN was trained by experimental pretreatment conditions and methane yields were successfully predicted by taking different USp parameters (different sonication times, SEA values and incremental soluble chemical oxygen demand % values) as input variables (Scenarios 2, 3 and 4). Regression analyses showed values close to 1, indicating that the prediction of the ANN model correlated linearly with experimental data.

WOS: 000522876500069 In this study, NaOH pretreatment, H2SO4 pretreatment, thermal pretreatment and production temperature were optimized to ensure maximum methane yield from hazelnut shells (HS) using the response surface methodology (RSM). A Box-Behnken design was achieved with four different independent variables and one dependent variable (methane yield). A total of 29 tests were performed after pretreatment according to the RSM design and to different production temperatures, suggesting optimum values for NaOH pretreatment, H2SO4 pretreatment, thermal pretreatment and production temperature were 3.5% w/v, 2.56% v/v, 145.66 degrees C and 34.65 degrees C, respectively. Under these conditions, the RSM-predicted methane yield was 215.896 mL/g volatile solid (VS). The high R-2 value (0.9904) showed that the model could be applied effectively in the digestion of HS for the predicted methane yield according to the production temperature and pretreatments. In addition, lignocellulosic solubilisation was tested after pretreatment of the reactors according to the RSM operating conditions, which showed that the highest cellulose, hemicellulose and lignin solubilisation that could be achieved was 38.7% w/w (R-10), 36.9% w/w (R-22) and 50.5% w/w (R-10), respectively. The modified Gompertz model supported the experimental cumulative methane yields (CMYs). Sivas Cumhuriyet University Scientific Research Projects Unit (CUBAP) [M-747] This study was supported by the Sivas Cumhuriyet University Scientific Research Projects Unit (CUBAP) under project M-747. We appreciate their contribution.

WOS: 000520029100012 Turkey is currently the world's largest producer of hazelnuts. In this study, based on 2018 data, the electrical energy potential of hazelnut shells after anaerobic digestion has been calculated for various cities, namely Giresun, Ordu, Samsun, Trabzon, Duzce, Sakarya, Artvin, Rize, Gumushane, Sinop, Kastamonu, Bartin, Bolu, Tokat, Zonguldak and Kocaeli, all of which have commercial licenses for hazelnut production in Turkey. The total potential gain so determined was 131.55 GWh, with the highest for any single city (Ordu) found to be 46.42 GWh. The electrical energy that could potentially be generated that was calculated for each city was compared with their electricity consumption in terms of lighting, habitation, industrial use, business use and agricultural irrigation. It was determined that the energy generated for hazelnut-producing cities could potentially be almost twice as large as the electrical energy typically consumed by agricultural irrigation. Ordu's electricity energy generation would potentially meet 63.63%, 9.99% and 13.5% of its lighting, habitation and business energy needs, respectively. Giresun's energy potential with regard to this use of hazelnut shells would meet 15.79% of the electricity used by industry. When these values are taken into consideration, it seems clear that the electrical energy potential of hazelnut shells for these cities could offer a significant saving in terms of overall consumption.

WOS: 000509985900003 PubMed: 31918301 In this study, anaerobic digestion (AD) of hazelnut (Corylus colurna) husks (HH) was investigated by NaOH pretreatment at 1-6% w/w concentrations. The highest methane yield was 278.45 +/- 7.85 mL/g volatile solid (VS), and this was obtained in a 4% NaOH pretreated reactor. In this reactor, the methane yield increased by 162.2% compared to that in the control. The concentrations of volatile fatty acids (VFAs) varied during the digestion process according to the different NaOH pretreatment results. The highest lignosellulosic solubilizations were obtained in a 6% NaOH pretreated reactor. Furthermore, in the second part of kinetic studies, it was defined critical points for cumulative methane yield (CMY) in the Logistic model (LM). These points were the absolute acceleration point (PAA), maximum acceleration point (PAM), inflection point (PI), maximum deceleration point (PDM), and asymptotic deceleration point (PDA). Using these points on the CMY curves, the AD process of HH was mathematically interpreted and explained.