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- ItemBatch and continuous lactic acid fermentation based on a multi-substrate approach(Basel : MDPI AG, 2020) Olszewska-Widdrat, Agata; Alexandri, Maria; López-Gómez, José Pablo; Schneider, Roland; Venus, JoachimThe utilisation of waste materials and industrial residues became a priority within the bioeconomy concept and the production of biobased chemicals. The aim of this study was to evaluate the feasibility to continuously produce L-lactic acid from different renewable substrates, in a multi-substrate strategy mode. Based on batch experiments observations, Bacillus coagulans A534 strain was able to continuously metabolise acid whey, sugar beet molasses, sugar bread, alfalfa press green juice and tapioca starch. Additionally, reference experiments showed its behaviour in standard medium. Continuous fermentations indicated that the highest productivity was achieved when molasses was employed with a value of 10.34 g·L−1·h−1, while the lactic acid to sugar conversion yield was 0.86 g·g−1 . This study demonstrated that LA can be efficiently produced in continuous mode regardless the substrate, which is a huge advantage in comparison to other platform chemicals. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemStudy of Water Productivity of Industrial Hemp under Hot and Dry Conditions in Brandenburg (Germany) in the Year 2018(Basel : MDPI, 2020) Drastig, Katrin; Flemming, Inken; Gusovius, Hans-Jörg; Herppich, Werner B.Hemp (Cannabis sativa L.) is a high-yielding multi-purpose crop, but its hydrological functioning is poorly understood. Studies on the interception processes in hemp have been lacking so far. This study contributes to the understanding of the influences of evaporation of intercepted water and other hydrological fluxes within plants of two cultivars, “Santhica 27” and “Ivory”, on the water productivity. To determine water productivity and evaporation from interception, field measurements were conducted on plants of both cultivars at different stages of development. Precipitation (P), throughfall (TF), transpiration (T), and volumetric water content (VWC) were measured along with leaf area index (LAI) and yield of selected plant components. For the entire vegetation period, the cumulative P of 44 mm was converted into 13 mm TF (30%). The inferred evaporation of intercepted water (I) was high at 31 mm (71%). For the assessment water fluxes, the evaporation of intercepted water must be considered in the decision-making process. Besides the LAI, the plant architecture and the meteorological conditions during the cropping cycle seem to be the main factors determining I in the case of plants of both cultivars. Water productivity (WPDM) of the whole plant varied between 3.07 kg m−3 for Ivory and 3.49 for Santhica 27. In the case of bast yield, WPDM was 0.39 kg m-3 for Santhica 27 and 0.45 kg m−3 for Ivory. After the propagation of the uncertainties, the bandwidth of the WPDM of the whole plant was between 0.42 kg m−3 and 2.57 kg m−3. For bast fiber a bandwidth of the WP between 0.06 kg m−3 and 0.33 kg m−3 was calculated. The results show furthermore that even with a precise examination of water productivity, a high bandwidth of local values is revealed on different cultivars. However, generic WP values for fiber crops are not attainable.
- ItemMolecular monitoring of the poplar wood chip microbiome as a function of storage strategy(Barking : Elsevier, 2021) Zöhrer, Julia; Probst, Maraike; Dumfort, Sabrina; Lenz, Hannes; Pecenka, Ralf; Insam, Heribert; Ascher-Jenull, JudithOne of the most challenging aspects of using wood chips as renewable energy source is the loss of biomass related to storage. Therefore, we installed three outdoor industrial-scale piles (250 m³) of poplar wood chips and monitored the bacterial and fungal communities by next-generation sequencing over a storage period of 120 d. Two of the three piles were supplemented with calcium dihydroxide (Ca(OH)2) (1.5%, 3% w/w) in order to test its potential as alkaline stabilization agent to preserve woody biomass during storage. Shifts in the microbial community composition occurred almost entirely in the beginning of the storage experiment, which we attribute to the temperature rise of up to 60 °C within the first week of storage. Later, however, we found little changes. Independent of Ca(OH)2 concentration, a consortium of lignocellulolytic and thermotolerant microorganisms dominated the stored wood chip microbiota emphasizing their role as key players during wood decomposition. Although the addition of Ca(OH)2 altered the physicochemical properties of wood chips, it did not prevent loss of biomass. Especially the pH was increased in Ca(OH)2 treated piles. However, only minor differences in the microbial communities’ composition were detected following Ca(OH)2 addition, highlighting the microbes tolerance towards and adaptation to changing environmental conditions.
- ItemApplication of hue spectra fingerprinting during cold storage and shelf-life of packaged sweet cherry(Cham : Springer, 2020) Le Nguyen, Lien Phuong; Visy, Anna; Baranyai, László; Friedrich, László; Mahajan, Pramod V.Presented work investigated the application of a new color analysis technique in post-harvest life of sweet cherry (Prunus avium L. ‘Hudson’). The hue spectra fingerprinting creates a histogram of image colors by summarizing the saturation. The advantage of this calculation method is that vivid colors make peaks while neutral background color is eliminated without object segmentation. Partial Least Squares (PLS) regression was used to estimate reference parameters during 9 d cold storage at 10 ± 0.5 °C (RH = 90 ± 1%) and following 2 d shelf-life at 20 ± 0.5 °C. The reference parameters of respiration, weight loss, fruit firmness and total soluble solid (TSS) content were measured. Samples were split into seven groups according to the number of perforations of polypropylene film and fructose concentration of moisture absorber. It was observed that parameters TSS and fruit firmness were the most sensitive to the length of storage. Weight loss was affected significantly by packaging. All reference parameters were estimated by PLS model with R2 > 0.917, but weight loss and respiration obtained high estimation error of RMSE% = 48.02% and 11.76%, respectively. TSS and fruit firmness prediction were successful with RMSE% = 0.84% and 1.85%, respectively. Desiccation and color change of peduncle became visible in the green range of hue spectra. Color change of red fruit was observed with decreasing saturation in the red range of hue spectra. Our findings suggest that hue spectra fingerprinting can be a useful nondestructive method for monitoring quality change of sweet cherry during post-harvest handling and shelf-life. © 2020, The Author(s).
- ItemInvestigating Solid and Liquid Desiccant Dehumidification Options for Room Air-Conditioning and Drying Applications(Basel : MDPI, 2020) Naik, B. Kiran; Joshi, Mullapudi; Muthukumar, Palanisamy; Sultan, Muhammad; Miyazaki, Takahiko; Shamshiri, Redmond R.; Ashraf, HadeedThis study reports on the investigation of the performance of single and two-stage liquid and solid desiccant dehumidification systems and two-stage combined liquid and solid desiccant dehumidification systems with reference to humid climates. The research focus is on a dehumidification system capacity of 25 kW designed for room air conditioning application using the thermal models reported in the literature. RD-type silica gel and LiCl are used as solid and liquid desiccant materials, respectively. In this study, the application of proposed system for deep drying application is also explored. Condensation rate and moisture removal efficiency are chosen as performance parameters for room air conditioning application, whereas air outlet temperature is chosen as performance parameter for deep drying application. Further, for a given range of operating parameters, influences of air inlet humidity ratio, flow rate, and inlet temperature on performance parameters of the systems are investigated. In humid climatic conditions, it has been observed that a two-stage liquid desiccant dehumidification system is more effective for room air conditioning application, and two-stage solid desiccant dehumidification system is more suitable for deep drying application in the temperature range of 50 to 70 °C, while single-stage solid desiccant and two-stage combined liquid and solid desiccant dehumidification systems are more effective for low temperature, i.e., 30 to 50 °C deep drying application.
- ItemEffect of Liquid Hot Water Pretreatment on Hydrolysates Composition and Methane Yield of Rice Processing Residue(Basel : MDPI, 2021) López González, Lisbet Mailin; Heiermann, MonikaLignocellulosic rice processing residue was pretreated in liquid hot water (LHW) at three different temperatures (140, 160, and 180 °C) and two pretreatment times (10 and 20 min) in order to assess its effects on hydrolysates composition, matrix structural changes and methane yield. The concentrations of acetic acid, 5-hydroxymethylfurfural and furfural increased with pretreatment severity (log Ro). The maximum methane yield (276 L kg−1 VS) was achieved under pretreatment conditions of 180 °C for 20 min, with a 63% increase compared to untreated biomass. Structural changes resulted in a slight removal of silica on the upper portion of rice husks, visible predominantly at maximum severity. However, the outer epidermis was kept well organized. The results indicate, at severities 2.48 ≤ log Ro ≤ 3.66, a significant potential for the use of LHW to improve methane production from rice processing residue.
- ItemCase Study of Effects of Mineral N Fertilization Amounts on Water Productivity in Rainfed Winter Rapeseed Cultivation on a Sandy Soil in Brandenburg (Germany) over Three Years(Basel : MDPI, 2021) Drastig, Katrin; Kreidenweis, Ulrich; Meyer-Aurich, Andreas; Ammon, Christian; Prochnow, AnnetteDetailed knowledge about farm management practices and related hydrological processes on water productivity is required to substantially increase the productivity of precipitation water use in agriculture. With this in mind, the effect of the nitrogen (N) fertilization level on water productivity of winter oilseed rape (Brassica napus L.) was analyzed using a modeling approach and field measurements. In this first study of interception loss and water productivity in winter oilseed rape, the crop was cultivated in a field experiment on a sandy soil in Brandenburg (Germany) under five nitrogen fertilization treatments with 0, 60, 120, 180, and 240 kg mineral N ha−1 a−1. Based on data from three vegetation periods the water flows and the mass-based water productivity of seeds were calculated on a daily basis with the AgroHyd Farmmodel modeling software. As recommended from the recently developed guidelines of the FAO on water use in agriculture, the method water productivity was applied and uncertainties associated with the calculations were assessed. Economic profit-based water productivity (WPprofit) was calculated considering the costs of fertilization and the optimal level of N fertilization, which was determined based on a quadratic crop yield response function. Mean water productivity of seeds varied from 1.16 kg m−3 for the unfertilized control sample to 2.00 kg m−3 under the highest fertilization rate. N fertilization had a clearly positive effect on WPprofit. However, fertilizer application rates above 120 kg N ha−1 a−1 led to only marginal increases in yields. Water productivity of seeds under the highest fertilization rate was only insignificantly higher than under medium application rates. The optimum N level for the maximal WPprofit identified here was higher with 216 kg N ha−1 a−1. The conclusion is that further research is needed to investigate the interaction between fertilization and other farm management practices.
- ItemEnergy Systems and Applications in Agriculture(Basel : MDPI, 2022) Sultan, Muhammad; Mahmood, Muhammad Hamid; Ahamed, Md Shamim; Shamshiri, Redmond R.; Shahzad, Muhammad Wakil[No abstract available]
- ItemInvestigation of the Effects of Torrefaction Temperature and Residence Time on the Fuel Quality of Corncobs in a Fixed-Bed Reactor(Basel : MDPI, 2022) Orisaleye, Joseph I.; Jekayinfa, Simeon O.; Pecenka, Ralf; Ogundare, Adebayo A.; Akinseloyin, Michael O.; Fadipe, Opeyemi L.Biomass from agriculture is a promising alternative fuel due to its carbon-neutral feature. However, raw biomass does not have properties required for its direct utilization for energy generation. Torrefaction is considered as a pretreatment method to improve the properties of biomass for energy applications. This study was aimed at investigating the effects of torrefaction temperature and residence time on some physical and chemical properties of torrefied corncobs. Therefore, a fixed-bed torrefaction reactor was developed and used in the torrefaction of corncobs. The torrefaction process parameters investigated were the torrefaction temperature (200, 240, and 280 °C) and the residence time (30, 60, and 90 min). The effects of these parameters on the mass loss, grindability, chemical composition, and calorific value of biomass were investigated. It was shown that the mass loss increased with increasing torrefaction temperature and residence time. The grinding throughput of the biomass was improved by increasing both the torrefaction temperature and the residence time. Torrefaction at higher temperatures and longer residence times had greater effects on the reduction in particle size of the milled corncobs. The calorific value was highest at a torrefaction temperature of 280 °C and a residence time of 90 min. The energy yield for all treatments ranged between 92.8 and 99.2%. The results obtained in this study could be useful in the operation and design of torrefaction reactors. They also provided insight into parameters to be investigated for optimization of the torrefaction reactor.
- ItemCalculation of ventilation rates and ammonia emissions : Comparison of sampling strategies for a naturally ventilated dairy barn(San Diego, Calif. : Academ. Press, 2020) Janke, David; Willink, Dylia; Ammon, Christian; Hempel, Sabrina; Schrade, Sabine; Demeyer, Peter; Hartung, Eberhard; Amon, Barbara; Ogink, Nico; Amon, ThomasEmissions and ventilation rates (VRs) in naturally ventilated dairy barns (NVDBs) are usually measured using indirect methods, where the choice of inside and outside sampling locations (i.e. sampling strategy) is crucial. The goal of this study was to quantify the influence of the sampling strategy on the estimation of emissions and VRs. We equipped a NVDB in northern Germany with an extensive measuring setup capable of measuring emissions under all wind conditions. Ammonia (NH3) and carbon dioxide (CO2) concentrations were measured with two Fourier-transform infrared spectrometers. Hourly values for ventilation rates and emissions for ammonia over a period of nearly a year were derived using the CO2 balance method and five different sampling strategies for the acquisition of indoor and outdoor concentrations were applied. When comparing the strategy estimating the highest emission level to the strategy estimating the lowest, the differences in NH3 emissions in winter, transition, and summer season were +26%, +19% and +11%, respectively. For the ventilation rates, the differences were +80%, +94%, and 63% for the winter, transition and summer season, respectively. By accommodating inside/outside concentration measurements around the entire perimeter of the barn instead of a reduced part of the perimeter (aligned to a presumed main wind direction), the amount of available data substantially increased for around 210% for the same monitoring period.