Type Of Nitrogen Source Research Articles

Decoupling soil community structure, functional composition, and nitrogen metabolic activity driven by salinity in coastal wetlands

Coastal wetlands, being a multifaceted and crucial global ecosystem, are facing significant impacts from diverse environmental alterations, particularly soil salinization. Concurrently, the escalation of extreme climate events, such as global warming, presents complex challenges for the protection and restoration efforts. Previous researches concerning microbial communities in the context of climate with continous line numbering change have predominantly concentrated on their structural aspects, with limited attention given to establishing relationships between community structure and functional attributes. In this study, a two-year investigation was conducted on conventional coastal wetland ecosystems, considering variations in salinity and seasonal temperature. Utilizing high-throughput 16S rRNA sequencing, isotope technology, and other methods to explore the bacterial community, nitrogen cycling functional groups, and nitrogen reduction process. This research aims to assess the holistic impacts of significant global environmental changes on microbial communities. The results suggest that salinity, acting as an environmental filter, has a significant impact on the microbial community composition. It leads to a decrease in species abundance, an increase in deterministic processes and the nesting of community succession, while also reducing the stability of microbial ecological networks. The mechanism by which soil salinity impacts bacterial communities involves three main aspects: direct effects, positive climate regulation, and negative regulation of soil properties. Surprisingly, soil salinity exerts a mild inhibitory influence on microbial functional genes and metabolic activity. The primary factors involved in the nitrogen reduction process include electron donors/acceptors, types of nitrogen sources, and organic carbon. The three processes are interconnected due to the impact of environmental factors and signal transmission among microbial populations. This study offers a novel scientific framework for the rehabilitation and enhancement of saline-alkali coastal ecosystems in the face of impending global changes. It achieves this by investigating the varied response patterns exhibited by microbial communities and ecological functional metabolism under salinity-induced stress.

Optimization of Lipid Production of Rhodosporidium toruloides from Various Substrates

Background and Aim: In recent years, bioenergy has received a lot of attention from a technical point of view due to its ability to use reversible resources and its applicability worldwide. Biodiesel is a non-toxic, safe, renewable, and degradable fuel that is obtained from natural sources, such as vegetable oils, food waste oils, animal fats, algae, and microorganisms. This study aimed to optimize the lipid production of Rhodosporidium toruloides as a biofuel from different substrates. Materials and Methods: In this experimental laboratory study, after lipid extraction from Rhodosporidium toruloides CECT1137, cell biomass, nitrogen, and sugar consumption were measured according to the Bly and Dyer method. Then, using gas chromatography, the produced lipid compounds were identified, and lipid production was optimized by the one-factor method (type of nitrogen source and KH2PO4) and the Taguchi method (carbon and nitrogen source, temperature, pH, centrifuge, and time). Finally, the feasibility of mutation was investigated using UV to optimize lipid production. Results: The amount of lipid produced by Rhodosporidium toruloides was 4.95 g/l, which, after optimization by the Taguchi method, reached 8.54 g/l. Cell biomass, residual nitrogen, and consumed sugar were measured as 14.05, 0.19, and 28.85 g/l, respectively. Optimal production conditions were estimated by Taguchi, including 80 g/l carbon source, 1 g/l nitrogen source, 25 ° C, pH = 5.5, centrifuge at 180 rpm, and 96 hours. Most lipids produced were oleic acid and palmitic acid. Lipid production increased after UV exposure. Conclusion: The results showed that Rhodosporidium toruloides can accumulate a significant amount of lipid in its cells and can be a good alternative to plants and other sources of fuel production.

Cercospora leaf spot management with nitrogenous fertilizers in cotton is dependent on the disease amount in the plant canopies

The aim of this study was to examine the impact of both organic and inorganic nitrogen fertilizers on the intensity and epidemiological components of Cercospora leaf spot across three different canopies of cotton plants, specifically the variety DP ACALA 90, under field conditions. Fertilizers used in the study included bovine manure, Jatropha curcas seedcake, poultry manure, and urea (the latter serving as a control). These were applied at 20 days after plant emergence and then during the flowering stage until the total nitrogen (N) dose reached 50, 100, 150, or 200 kg N per hectare. The incidence and severity of the disease were assessed starting at the reproductive stage B1 (the first visible flower bud) across the lower, middle, and upper canopies of four cotton plants, with six evaluations conducted over time. To calculate the initial inoculum (Y0) and the disease progress rate (r), the Exponential, Gompertz, and Logistic models were employed based on temporal data. The study was designed as a randomized complete block with a 4x4 factorial arrangement (fertilizer type x dose), and mean comparisons were made using Tukey's test (p ≤ 0.05). It was found that disease intensity within each canopy level varied in response to the type of nitrogen source and the applied dose, with the severity of the disease (including the area under the disease progress curve) being particularly influenced. A significant interaction between the type of fertilizer and the dose regarding the intensity of Cercospora leaf spot was observed. The Exponential model most accurately depicted the disease's temporal progression. Notably, poultry manure and urea were the fertilizers that most adversely influenced the intensity and initial inoculum (Y0) of Cercospora leaf spot across the various canopies of the cotton plants. The findings suggest that the use of organic fertilizers in cotton cultivation could represent a viable sustainable management strategy.

Nitrogen-cycling microbial communities respond differently to nitrogen addition under two contrasting grassland soil types.

The impact of nitrogen (N) deposition on the soil N-transforming process in grasslands necessitates further investigation into how N input influences the structural composition and diversity of soil N-cycling microbial communities across different grassland types. In this study, we selected two types of grassland soils in northwest Liaoning, temperate steppe and warm-temperate shrub, and conducted short-term N addition experiments using organic N, ammonium N, and nitrate N as sources with three concentration gradients to simulate N deposition. Illumina MiSeq sequencing technology was employed to sequence genes associated with N-cycling microbes including N-fixing, ammonia-oxidizing and denitrifying bacteria, and ammonia-oxidizing archaea. The results revealed significant alterations in the structural composition and diversity of the N-cycling microbial community due to N addition, but the response of soil microorganisms varied inconsistent among different grassland types. Ammonium transformation rates had a greater impact on soils from temperate steppes while nitrification rates were more influential for soils from warm-temperate shrubs. Furthermore, the influence of the type of N source on soil N-cycling microorganisms outweighed that of its quantity applied. The ammonium type of nitrogen source is considered the most influential driving factor affecting changes in the structure of the microbial community involved in nitrogen transformation, while the amount of low nitrogen applied primarily determines the composition of soil bacterial communities engaged in nitrogen fixation and nitrification. Different groups of N-cycling microorganisms exhibited distinct responses to varying levels of nitrogen addition with a positive correlation observed between their composition, diversity, and environmental factors examined. Overall findings suggest that short-term nitrogen deposition may sustain dominant processes such as soil-N fixation within grasslands over an extended period without causing significant negative effects on northwestern Liaoning's grassland ecosystems within the next decade.

An Optimization Design for the Resource Utilization of Grape Branches Based on the Orthogonal Test and Gray Relational Analysis Method

Composting is an environment-friendly and sustainable way to transform grape branches (GBs) into a useful product. Different parameters can differently affect fertilizer quality. Here, the compost product nutrient content was evaluated using an L9 orthogonal array (parameters, nitrogen source: chicken manure, sheep manure, urea; stirring temperature: 50, 60, 70 °C; initial pH: 6, 7, 8; conditioning agent: calcium superphosphate, zeolite, and copper sulfate). Among the treatments, the T3 (chicken manure, 70 °C, pH = 8, copper sulfate), T2 (chicken manure, 60 °C, pH = 7, zeolite), and T9 (urea, 70 °C, pH = 7, calcium superphosphate) had high gray relational grades (0.7424, 0.7132, 0.7110, respectively). The nitrogen source type (R = 0.1140) had the greatest influence on the nutrient content of the final product, followed by the stirring temperature (R = 0.1104), the conditioning agent (R = 0.0522), and the initial pH (R = 0.0408). Finally, the best nitrogen source of the grape branch compost was chicken manure, the best stirring temperature was 70 °C, the best initial pH was 7, and the best conditioning agent was zeolite. An experimental verification showed that the weighted correlation degree of the optimal treatment predicted by the orthogonal experiment increased by 3.63%.

Pengaruh Perbedaan Jenis dan Konsentrasi Sumber Nitrogen (NaNO3 dan urea) terhadap Produksi Biomasa Spirulina Platensis

The goal of this study was to investigate the effect of the concentration and the type of nitrogen sources in the cultivation medium on the production of biomass and biochemical content (carbohydrates, proteins, fats) in the Spirulina platensis biomass. Types of nitrogen sources included NaNO3 and urea, where the concentrations were varied from 0.5 to 3.5 g/L. The results showed that the use of urea tended to produce more S. platensis biomass than the use of NaNO3. The best concentrations that produced the highest biomass were NaNO3 2.5 g/L (biomass 0.6745 g/L) and urea 0.5 g/L (biomass 0.7158 g/L). The use of urea also tended to produce a higher specific growth rate and a shorter doubling time than the use of NaNO3. The high concentration of nitrogen sources caused the pH of the medium to increase more rapidly due to the accumulation of ammonium in the medium. Using NaNO3 can produce biomass with a higher protein content (28.34-36.98%) than using urea (25.86-33.52%).

Reducing higher alcohols by integrating indigenous Saccharomyces cerevisiae, nitrogen compensation, and chaptalization methods during fermentation of kiwifruit wine

The concentration of higher alcohols in kiwifruit wine is often excessive, posing the risk of toxic effects on the health of drinkers. To lower the higher alcohol content in kiwifruit wine, this study tested five indigenous S. cerevisiae strains, two types of nitrogen sources (inorganic and organic), and five chaptalization methods. The results showed that the total higher alcohol production of three versions of resulting kiwifruit wines: (i) fermented by S. cerevisiae LFN524, (ii) adding 300 mg/L diammonium phosphate (DAP), using the Th-Tw-S chaptalization strategy, were decreased by 32%, 43%, and 26%, respectively. Integrating the above technologies, that is, fermentation by S. cerevisiae LFN524, the addition of 300 mg/L DAP, and use of Th-Tw-S chaptalization strategy, for pilot-scale kiwifruit wine production, showed a 52% reduction in total higher alcohol production (222.00 ± 24.91 mg/L) and a 14% reduction in total acidity production (13.32 ± 0.06 g/L). In pilot-scale kiwifruit wine, sensory analysis showed that with the reduction of higher alcohol content, the typical aromas of kiwifruit wine became more prominent, resulting in a purer aroma of kiwifruit wine. Taken together, the results of this research provide a viable means for producing lower-higher-alcohol kiwifruit wines.

Free fatty acids in sunflower oil soap stock progressed the sophorolipid production by Candida catenulata

AbstractSophorolipids are a group of surface‐active glycolipid compounds that can be synthesized by several yeasts, especially the Candida genera. Soap stock is a by‐product of vegetable oils refinery that enriches mono‐unsaturated fatty acids, and its application is interesting as a low‐cost industrial residue in sophorolipid production. In this study, the sophorolipid production was evaluated by Candida catenulate KP324968, using sunflower oil soap stock and glucose as the hydrophobic and hydrophilic carbon sources, respectively. The results indicated the ratio of hydrophobic to a hydrophilic carbon source, initial pH, and type of nitrogen source had significant roles in the performance of the cells. The highest specific biomass growth rate was about 0.0447 ± 0.0013 h−1 and a sophorolipid production rate of 49.96 ± 0.33 mg L−1 h−1 was obtained at a soap stock‐to‐glucose ratio of 1, initial pH of 5.5, and temperature of 30°C. The addition of organic nitrogen sources such as yeast extract and urea obtained a higher sophorolipid production in comparison with ammonium nitrate and potassium nitrate as the mineral nitrogen sources. Usage of both yeast extract and urea increased the sophorolipid production rate by 4.4% and 6.9%, in comparison with separate usage of yeast extract and urea, respectively. The characterization of the sophorolipid confirmed an emulsification index of about 30 ± 2.9% for diesel‐in‐water and 50 ± 3.5% for sunflower oil‐in‐water systems. The critical micelle concentration was determined at 280 mg L−1. The produced sophorolipid at a concentration of 500 mg L−1 showed an antibacterial capacity about of 95.4 ± 1.1%, and 44.7 ± 0.8% against Bacillus subtilis (Gram‐positive) and Escherichia coli (Gram‐negative) bacteria, respectively.

Dose–effect of nitrogen regulation on the bioremediation of diesel contaminated soil

Nitrogen regulation is an effective method to enhance the bioremediation of hydrocarbon contamination. In this study, various dosages of two types of nitrogen sources were spiked to the diesel contaminated soil in a 60-day microcosmic experiment. The results showed that the total petroleum hydrocarbon (TPH) degradation rate improved from control test of 32.03% to the highest of 44.74% with nitrogen spiking. Peptone and KNO3 significantly improved the bioremediation of diesel-contaminated soil, peptone was more effective than KNO3 at low dosage. The soil C:N ratio of 20:1 (T1 treatment with the addition of peptone) was the optimal treatment. The effect of two nitrogen on soil pH was reverse, high dose of peptone addition significantly increased soil pH, but KNO3 addition significantly decreased soil pH. The soil bacteria diversity decreased significantly in the high dose Peptone treated soil, while the changes of bacteria diversity of KNO3 treated soil was just opposite. Furthermore, nitrogen regulation significantly changed the structure of soil bacterial community, Rubrobacter, Solirubrobacter and Gaiella, which belonging to Actinomycetota, were identified as the three common genus with hydrocarbon degrading ability in different nitrogen amended soil. Peptone and KNO3 had different mechanisms on the bioremediation of diesel contaminated soil. The properties of these two nitrogen sources provides us with more options for the bioremediation of hydrocarbon contaminated acid or alkaline soil.

Optimization of submerged fermentation conditions for glucanase production by Burkholderia pyrrocinia B1213 using Jiuzao

This study optimized the fermentation conditions for producing glucanase from Burkholderia pyrrocinia B1213 using Jiuzao, a residue from Baijiu distillation, as the carbon source. The effects of Jiuzao particle size and concentration, type of nitrogen source, urea concentration, initial pH, inoculum size, loading volume, shaking speed, temperature, surfactant type and incubation time on glucanase production by B. pyrrocinia B1213 were investigated separately through single factor design. Then, five variables, Jiuzao concentration, inoculum size, initial pH, temperature and incubation time, were found to significantly affect glucanase production using the Plackett-Burman design. Following, the optimal conditions for glucanase production by B. pyrrocinia B1213 were found using the steepest ascent path and response surface methodology designs as: particle size, 40-60 mesh; Jiuzao concentration, 58.4 g/L; urea concentration, 8 g/L; initial pH, 6; loading volume, 15 mL/250 mL; inoculum size, 0.63% (v/v); temperature, 26 °C; shaking speed, 160 rpm; and incubation time, 120 h. Under these conditions, the glucanase activity of the B. pyrrcinia B1213 strain was 1336 U/mL, producing the biological enzymes needed in Baijiu making from a by-product. This study has provided experimental data and theoretical information for using B. pyrrcinia B1213 in Baijiu production. Keywords: Burkholderia pyrrocinia; Glucanase; Response surface methodology; Fermentation conditions; Jiuzao

Hydrolysis of Waste Cooking Oil Using Rhizopus oryzae to Produce Free Fatty Acids

Waste cooking oil is waste produced from palm oil after it has been heated and fried at high temperatures, and it can pollute the environment. One effort to reuse waste cooking oil is a fermentation processe that produces free fatty acids with the help of Rhizopus oryzae as a biocatalyst. Variations in initial substrate concentration ranged from 10 g/L to 70 g/L, followed by varied types of nitrogen sources, namely malt extract, beef extract, (NH2)2CO, NH4Cl, and (NH4)2SO4 at a concentration of 70 g/L to determine free fatty acid concentration. Fermentation was carried out for 7 days. The analysis carried out included the concentration of free fatty acids, biomass, and YP/X value. The optimum initial used cooking oil substrate was obtained at a concentration of 30 g/L with a YP/X value of 13.63%, a free fatty acid concentration of 2.13 g/L and a dry cell weight of 15.48 g/L. The best nitrogen source is beef extract with a Yp/x value of 11.78%, a free fatty acid concentration of 2.02 g/L and a dry cell weight of 17.0 g/L

Effect of nitrogen source and spray conditions on the integral biotrickling filter operation for hydrophobic volatile organic compounds

A nutrient solution containing major and trace elements plays a crucial role in biotrickling filter (BTF) operation in practical applications. This study conducted a series of experiments on the BTF packed with integral filters using two types of nitrogen sources under different spray conditions. The rapid start-up was observed in the BTF feeding with ammonium tartrate-N (AT-N) nutrient solution. Heterotrophic nitrification and denitrification were observed by monitoring the concentration of ammonia-N, nitrite-N, nitrate-N, PO43− and SO42− in the nutrient solution. The BTF performance under two different types of the nutrient solutions were detected up to ∼90% at the inlet toluene concentration of 300–700 mg∙m−3. The BTF packed with integral filters exhibited the stable performance with the change of nitrogen source and could be steadily operated at a wide pH range of 5.5–8.5. To illustrate the effect of the two types of nitrogen sources on the biofilm, metagenomic sequencing was used to assess the microbial diversity and functional genes of biofilm on the integral filters. The results showed that the application of AT-N nutrient solution increased the functional genes of denitrification in the microorganisms on the filters. Furthermore, the more stable performance of BTF was achieved by using the AT-N nutrient solutions, which might be beneficial to the long-term operation of BTF packed with honeycomb integral packing.

Growth of Arthrospira platensis with Different Nitrogen Sources

Microalgae is a promising and innovative biological resource. Indonesia has the potential for the development of microalgae production. One of the microalgae that have high economic value is Arthrospira platensis. In the production of microalgae, the development of suitable media and environmental conditions need to be factors that must be considered. This study aimed to analyze the effect of different nitrogen sources and nitrogen doses and their interaction on the growth of microalgae Arthrospira platensis cultured in fresh water. In addition, analyzing the water quality of Arthrospira platensis culture media. This study used an experimental method of Completely Randomized Factorial Design) with two factors. The first factor is the nitrogen source (Sodium nitrate, Potassium nitrate, and Calcium nitrate). The second factor is the dose of nitrogen source (2 g/l.2.5 g/l.3 g/l). The main parameter observed was microalgae growth, while the supporting parameter was the water quality which affected the growth of Arthrospira platensis. The highest density results were found in the provision of a nitrogen source of Ca(NO3)2 3 g/l, which was 370,000 cells/ml. The results of the ANOVA test showed that the type of nitrogen source, the dose, and the interaction between the two affected the specific growth rate of Arthrospira platensis. The environmental conditions during culture ranged from 20.2°C-26.2°C, pH values ​​8.95 – 10.18, and dissolved oxygen 9.17 – 9.77 mg/L.

Recent Advances in N-O Bond Cleavage of Oximes and Hydroxylamines to Construct N-Heterocycle.

Oximes and hydroxylamines are a very important class of skeletons that not only widely exist in natural products and drug molecules, but also a class of synthon, which have been widely used in industrial production. Due to weak N-O σ bonds of oximes and hydroxylamines, they can be easily transformed into other functional groups by N-O bond cleavage. Therefore, the synthesis of N-heterocycle by using oximes and hydroxylamines as nitrogen sources has attracted wide attention. Recent advances for the synthesis of N-heterocycle through transition-metal-catalyzed and radical-mediated cyclization classified by the type of nitrogen sources and rings are summarized. In this paper, the recent advances in the N-O bond cleavage of oximes and hydroxylamines are reviewed. We hope that this review provides a new perspective on this field, and also provides a reference to develop environmentally friendly and sustainable methods.

Insight into humification of mushroom residues under addition of Rich-N sources: Comparing key molecular evolution processes using EEM-PARAFAC and 2D-FTIR-COS analysis

Accelerating the humification of organic solid waste is one of the most important issues in composting. This present study aims to study and compare the humification process of different rich-N sources (chicken manure, cattle manure, and urea) addition during the composting of mushroom residues, from macro physicochemical properties to micro humic molecular structure evolution process. The physicochemical elements and humic components were determined for evaluating the compost quality and humification degree as composting proceed. The coupled analysis of excitation-emission matrix with parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation with Fourier transform infrared spectrum (2D-FTIR-COS) were used to characterize the functional molecular structure evolution of dissolved organic matter during humification process. The results indicated that the rank order for humification level were the treatments of chicken manure (HM), urea (UM), cattle manure (CM), and single mushroom residue treatment (CK), with their humification index of 22.18%, 22.05%, 18.47%, and 16.52%, respectively. Humic substance, humic acid, and fulvic acid were obtained the highest in HM treatment with contents of 35.41 ± 0.86%, 23.32 ± 1.57%, and 10.97 ± 0.52%, respectively. The rich-N source addition enhanced the degradation of protein-like and polysaccharides-like substances in dissolved organic matter, thus accelerating the humification process of mushroom residues. The key structure evolution of dissolved organic matter in the HM treatment, in which the CO and CC stretching of quinone, amide, or ketone, and the C–O stretching of polysaccharides may be responsible for the faster formation of humus compared to the other nitrogen treatments. In this study, redundancy analysis indicated that the total nitrogen (TN) and nitrate nitrogen (NO3−-N) may be the potential indicators for determining the humification level as composting proceed. The result provides significant insight into the humification mechanism of mushroom residue under different types of nitrogen sources at the molecular level, and will be reference for improving the composting technique in practical field.

Thorough Investigation of the Effects of Cultivation Factors on Polyhydroalkanoates (PHAs) Production by Cupriavidus necator from Food Waste-Derived Volatile Fatty Acids

Volatile fatty acids (VFAs) have become promising candidates for replacing the conventional expensive carbon sources used to produce polyhydroxyalkanoates (PHAs). Considering the inhibitory effect of VFAs at high concentrations and the influence of VFA mixture composition on bacterial growth and PHA production, a thorough investigation of different cultivation parameters such as VFA concentrations and composition (synthetic and waste-derived VFAs) media, pH, aeration, C/N ratio, and type of nitrogen sources was conducted. Besides common VFAs of acetic, butyric and propionic acids, Cupriavidus necator showed good capability for assimilating longer-chained carboxylate compounds of valeric, isovaleric, isobutyric and caproic acids in feasible concentrations of 2.5–5 g/L. A combination of pH control at 7.0, C/N of 6, and aeration of 1 vvm was found to be the optimal condition for the bacterial growth, yielding a maximum PHA accumulation and PHA yield on biomass of 1.5 g/L and 56%, respectively, regardless of the nitrogen sources. The accumulated PHA was found to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with the percentage of hydroxybutyrate in the range 91–96%. Any limitation in the cultivation factors was found to enhance the PHA yield, the promotion of which was a consequence of the reduction in biomass production.

PENGARUH JENIS SUMBER NITROGEN TERHADAP KARAKTERISTIK NATA DE SAGO

Nata is a biotechnology product that utilizes Acetobacter xylinum in the fermentation process. Making nata requires materials that contain carbohydrates and nitrogen. The raw materials for making nata generally use coconut water, fruit extracts, and sago waste. Sago liquid waste can be used because it contains starch as a carbon source to form polysaccharides. In addition to starch content, making nata also requires nitrogen supply. Increased nitrogen supply can increase the amount of polysaccharide formed. This study aims to determine the effect of giving different types of nitrogen sources, namely urea, ZA, and touge extract and control without the addition of nitrogen on the characteristics of nata de sago. This study used the RAL method (Completely Randomized Design) which consisted of 4 treatments and 3 repetitions. The results showed that the addition of 1.5 g of urea produced the best nata characteristics based on thickness, color, and aroma, but based on texture characteristics the best value was obtained in the bean sprout extract treatment. The results of this study become an alternative to the use of sago leachate as a raw material for making nata and an alternative to the use of natural nitrogen sources from bean sprout extract which is organic and has no residue in the final product of nata.Key words: Nata de sago, nitrogen, organoleptic

Effect of process mode, nitrogen source and temperature on L-malic acid production with Aspergillus oryzae DSM 1863 using acetate as carbon source.

Malic acid, mainly used as acidulant and taste enhancer in the food industry, is currently produced from fossil resources. In this study, microbial L-malate production with the filamentous fungus A. oryzae using the carbon source acetate was evaluated. Acetate is for example contained in biomass-derived substrates such as lignocellulosic hydrolysates and condensates of fast pyrolysis, thus avoiding competition with food production. Since research on malic acid synthesis from acetate is limited and reported productivities and yields are low, this work aimed to improve the process. First, different cultivation temperatures were tested. This parameter was found to affect the ratio between malic and succinic acid, which is the major by-product of organic acid production with A. oryzae. At 32°C, the malate share was highest (53.7 ± 1.6%), while it was lowest at 38°C (43.3 ± 1.1%) whereas succinate represented the main product (51.5 ± 1.0%). Besides the temperature, the type of nitrogen source was also found to affect malate synthesis as well as biomass production. In the pre-culture, the biomass concentration was increased by a factor of 3.4–3.9, and germination started earlier with the complex nitrogen sources yeast extract, casein hydrolysate and peptone compared to the defined nitrogen source (NH4)2SO4. Especially with yeast extract, malate synthesis in the main culture was accelerated and the titer obtained after 48 h was about 2.6 times higher than that quantified with (NH4)2SO4. To reduce substrate inhibition in acetate medium, fed-batch and repeated-batch processes were evaluated using (NH4)2SO4 or yeast extract as nitrogen source. In the fed-batch process, the period of malate production was extended, and the maximum product concentration was increased to 11.49 ± 1.84 g/L with (NH4)2SO4 and 12.08 ± 1.25 g/L with yeast extract. In the repeated-batch process, the total acid production was highest within the first 240 h of fermentation, but optimization is required to maintain high production rates in later cycles. The lessons learned in this study will help in the development of further process strategies to maximize malate production using acetate as alternative substrate to the commonly used glucose.

Influence of hydrochloric acid concentration and type of nitrogen source on the electrochemical performance of TiO2/N-MoS2 for energy storage applications

In this work, nitrogen-doped molybdenum sulfide was directly deposited on titanium dioxide nanotubes substrate (TiO2/N-MoS2) during hydrothermal synthesis. The study focuses on the influence of hydrochloric acid concentration used for the synthesis, with the results indicating its essential role in thioacetamide hydrolysis and thus in the effectiveness of the N-MoS2 deposition. The electrode material itself is characterized by an initial capacitance of 320 mF cm−2 with 76 % capacitance retention after 10000 cycles. Moreover, the effect of nitrogen source on the physical and capacitive properties is investigated, revealing that the simultaneous addition of aniline and ammonium persulfate contributes to the improvement of crystallinity and overall electrochemical performance of the electrode material. The analysis of charge storage mechanisms also indicates that the introduction of nitrogen atoms significantly affects the contribution of diffusion-controlled processes. In the construction of a symmetrical device, the specific capacitance of 76 F g−1 and areal capacitance of 70 mF cm−2 with the superior coulombic efficiency and 84 % of capacitance retention after 15,000 cycles is observed, with 11.1 W kg−1 and 5193.4 Wh kg−1 of energy and power density of the device, respectively.

Optimization studies about efficient biobutanol production from industrial tea waste by Clostridium beijerinckii

The current study aims to evaluate industrial tea waste (ITW), which generated massive quantities annually, on biobutanol production by Clostridium beijerinckii. Some critical parameters for biobutanol production such as initial ITW sugar loading (20,40,60,80 g/L), fermentation time (24–120 h), type of nitrogen sources (whey powder and yeast extract) and concentrations (1,2,4,8 g/L), mineral salts such as MgSO4·7H2O (0.05–0.4 g/L), FeSO4·7H2O (0.005–0.04 g/L), ZnSO4·7H2O (0.001–0.02 g/L) were optimized. C. beijerinckii produced the highest total ABE and biobutanol as 9.73 g/L and 6.21 g/L in the presence of 0.1 g/L MgSO4·7H2O, 0.01 g/L FeSO4·7H2O and 0.001 g/L ZnSO4·7H2O with 40 g/L ITW sugar. Furthermore, at optimized conditions, the biobutanol productivity and yield improved approximately 2 and 2.4 times at the end of 96 h compared with standard P2 medium, respectively. To the best of our knowledge, this is the first report about using ITW which is a promising feedstock for biobutanol production.