Optimal Nitrogen Source Research Articles

Detection and Characterization of Lasiodiplodia pseudotheobromae Associated with Stem Wilt on Ficus hirta (Vahl) and Its Fungicidal Sensitivity

Ficus hirta Vahl is an important medicinal and edible plant in southern China. Typical green wilting on leaves and brown necrotic spots on the stems were observed since mid-June 2022 in an F. hirta plantation in Danzhou, Hainan (China). The disease rapidly developed, causing stem withering and plant death. The disease incidence varied from 45 to 85% prevalence, and the average disease index was 47 in the period of outbreak during June to December. Relevant hypothetical fungi were isolated from naturally infected wilt tissues, and their pathogens were preliminarily confirmed to be Lasiodiplodia pseudotheobromae through hypothetical fungal culturing, morphological characteristic observations, and pathogenicity testing on F. hirta plants. The phylogenetic tree constructed based on partial ITS, translation elongation factor (TEF1-α), and the β-tubulin gene (TUB2) further confirmed the identity of the pathogen as L. pseudotheobromae. Further research on the biological characteristics of L. pseudotheobromae showed that the optimal temperature for the growth of L. pseudotheobromae was PDA medium, with a temperature of 30 °C and pH of 6. Peptone and fructose were the optimal nitrogen and carbon sources for it. In vitro efficacy testing showed that among eleven fungicides, fluazinam and prochloraz had the highest mycelial growth inhibition, with an EC50 of 0.0477 µg/mL and 0.0996 µg/mL, respectively. And the two fungicides showed significant control on the stem wilt of F. hirta in a pot. To our knowledge, this is the first comprehensive report on the pathogen identification and biological characteristics of L. pseudotheobromae infecting the stem wilt of F. hirta in China. Our results provide important information for developing effective management measures and controlling this disease.

Metabolomics analysis based on UHPLC-QTOF-MS/MS to explore the synthesis mechanism and culture conditions optimization of Penicillium EF-2 exopolysaccharide

Penicillium exopolysaccharide (EPS) inhibits galactose lectins and enhances immunity. However, EPS production is low and its synthesis mechanism remains unclear. Penicillium EF-2 strains with high EPS production were selected for this study, and Penicillium fermentation conditions were subsequently improved. The optimal culture conditions were 30 g/L lactose, 6 g/L yeast extract powder, 4 d seed age, 10 % inoculation amount, 3 d of secondary fermentation time, and the final EPS yield was 3.97 g/L. UHPLC-Q-TOF-MS/MS was used to explore the mechanism of EPS synthesis at the metabolic level. Optimal carbon source: lactose and optimal nitrogen source: yeast extract can provide precursors for EPS synthesis through related metabolic pathways. Moreover, regulating the energy, vitamin, and lipid metabolic pathways created favourable conditions for EPS synthesis and secretion. These findings explain the mechanism of EPS synthesis at the metabolic level and provide a theoretical basis for optimising and industrialising EPS production.

Characterization and Fungicide Sensitivity of Phaeosphaeriopsis obtusispora That Causes Marginal Leaf Blight in Agave hybrid H.11648.

Sisal is an important tropical cash crop in southern China. Unfortunately, it is threatened by various diseases. In 2022, a new disease tentatively named marginal leaf blight disease (MLBD) was first observed in sisal fields across Guangxi and Guangdong provinces, with an incidence rate ranging from 13% to 30%. In this work, to isolate and identify the pathogens causing MLBD, sisal leaves exhibiting the typical MLBD symptoms were collected, and nine strains were obtained. Pathogenicity tests, morphological observations, and phylogenetic analyses confirmed that two strains, namely 22GX1-3 and 22GD1-4, identified as Phaeosphaeriopsis obtusispora, were the causative pathogens of MLBD. Further investigations into the biological characteristics of P. obtusispora showed that its mycelia exhibited optimal growth on PDA medium, with the most favourable temperature and pH being 25 °C and 7.0, respectively. The mycelia could grow in temperatures ranging from 10 °C to 32 °C but ceased at 35 °C. Lactose and yeast extract powder were also identified as the optimal carbon and nitrogen sources, respectively. Additionally, the effectiveness of various control agents was assessed on a single strain, 22GX1-3. Among the twelve fungicides tested, difenoconazole was proven the most effective, with an EC50 value of 0.5045 µg/mL. To our knowledge, this is the first report for sisal MLBD caused by P. obtusispora. Our results provide crucial pieces of information for the development of effective management strategies to control sisal MLBD caused by P. obtusispora.

The Identification of Kabatiella zeae as a Causal Agent of Northern Anthracnose of Sorghum in China and Estimation of Host Resistance.

Sorghum northern anthracnose is a leaf disease affecting sorghum, which results in plant death and substantial yield loss. This study aimed to effectively understand the disease, clarify its biological characteristics, and evaluate the resistance of germplasm resources. A field sample was collected to isolate and purify the pathogen. The pathogen, identified as Kabatiella zeae Narita et Hiratsuka using both morphological and molecular techniques, was further confirmed as the causative agent of northern anthracnose of sorghum following Robert Koch's principles. The results revealed the optimal culture temperature to be 25 °C, preferred dark culture conditions, and the best growth on potato glucose agar medium with sucrose and L-leucine as the optimal carbon and nitrogen sources, respectively. A total of 138 sorghum germplasm resources were inoculated and evaluated using the isolated pathogen, with 20 lines (14.49%) exhibiting high resistance, 18 lines (13.04%) showing disease resistance, 27 lines (19.57%) demonstrating medium resistance, 37 lines (26.81%) being susceptible, and 36 lines (26.09%) classified as highly susceptible. The indoor fungicide screening was conducted through pathogen medium application, and enilconazole, pyraclostrobin, methylthiophanate, and flusilazole were screened for the best fungicide inhibition with a 100% inhibition rate compared with the control. This study provides reference for field pharmaceutical control in sorghum production.

Isolation, Identification and Characterization of Leptosphaerulina trifolii, the Causative Agent of Alfalfa Leptosphaerulina Leaf Spot in Inner Mongolia, China

Leptosphaerulina leaf spot, caused by Leptosphaerulina trifolii, is a major disease of alfalfa (Medicago sativa), leading to noticeable losses. From 2022 to 2023, we collected samples of alfalfa with symptoms of the disease from different locations in Inner Mongolia, China. Nine fungal isolates recovered from these samples were identified through morphological traits and a maximum likelihood phylogeny based on concatenated partial sequences of ITS, 28S, and rpb2. A pathogenicity test on alfalfa confirmed the pathogenicity of the isolates on alfalfa. Analysis of physiological traits of L. trifolii revealed optimal mycelium growth at 20 °C and a pH range of 5 to 7, with soluble starch as the preferred carbon source and yeast extract as the optimal nitrogen source. The pathogen thrived in V8-juice agar and oat agar media. This study confirms L. trifolii as the causative agent of Leptosphaerulina leaf spot of alfalfa in Inner Mongolia and provides valuable insights into its optimal growth conditions. These findings enhance the understanding and management of this disease in alfalfa fields.

Exploiting the roles of nitrogen sources for HEA increment in Cordyceps cicadae.

Cordyceps cicadae, as a new food ingredient, is a valuable edible and medicinal fungi. However, its resources are severely depleted due to environmental limitations and excessive harvesting practices. N6-(2-hydroxyethyl) adenosine (HEA), as an important product of Cordyceps cicadae, has the potential to be used in medical industry due to its diverse disease curing potential. However, the disclosure of HEA synthesis still severely limited its application until now. In this study, the kinetic curves for adenosine and HEA under shaker fermentation were explored. The kinetics of HEA and adenosine production exhibited a competitive pattern, implicating a possibility of sharing a same step during their synthesis. Due to HEA as a derivative of nitrogen metabolism, the effect of different nitrogen sources (peptone, yeast extract, ammonium sulfate, diammonium oxalate monohydrate, ammonium citrate dibasic, and ammonium citrate tribasic) on HEA production in Cordyceps cicadae strain AH 10-4 had been explored under different incubation conditions (shaker fermentation, stationary fermentation, and submerged fermentation). Our results indicated that the complex organic nitrogen sources were found to improve the accumulation of HEA content under shaker fermentation. In contrast, the optimal nitrogen source for the accumulation of HEA under stationary fermentation and submerged fermentation was ammonium citrate tribasic. But submerged fermentation obviously shortened the incubation time and had a comparable capacity of HEA accumulation by 2.578 mg/g compared with stationary fermentation of 2.535 mg/g, implicating a possibility of scaled-up production of HEA in industry by submerged fermentation. Based on the dramatic HEA production by ammonium sulfate as nitrogen resources between stationary and shaker fermentations, alanine, aspartate and glutamate as well as arginine metabolic pathway were related to the production of HEA by comparative transcriptome. Further investigation indicated that glutamic acid, which is an analog of Asp, showed an optimum production of HEA in comparison with other amino acids.

Optimization of Fermentation Culture Medium for Sanghuangporus alpinus Using Response-Surface Methodology

The newly identified Sanghuangporus alpinus species of the Sanghuang mushroom genus has been found to possess significant medical benefits. However, the current artificial cultivation technology has not reached the requisite maturity. The response-surface methodology (RSM) was used to optimize the Sanghuangporus alpinus culture medium formulation and evaluate the functional activity of S. alpinus exopolysaccharides. First, a single-factor experiment was conducted to screen for optimal carbon and nitrogen sources for S. alpinus. Then, using Box–Behnken’s central composite design, a response-surface experiment was conducted to determine optimal culture parameters. Finally, the rationality of those parameters was assessed in a shaking flask experiment. The optimal culture parameters, determined through regression analysis, were 20.20 ± 0.17 g/L fructose (carbon source), 7.29 ± 0.10 g/L yeast extract (nitrogen source), and 0.99 ± 0.01 g/L dandelion. With optimization, the S. alpinus yield increased to 12.79 ± 1.41 g/L, twice that obtained from the initial culture medium. The S. alpinus exopolysaccharide exhibited an excellent antioxidant capacity, with the strongest scavenging effect noted on ABTS free radicals (lowest half-inhibitory concentration: 0.039 mg/mL). Additionally, this exopolysaccharide effectively inhibited various cancer cells, exhibiting the strongest activity against human glioma cells U251 (half-inhibitory concentration: 0.91 mg/mL). The RSM used to optimize the fermentation culture parameters of S. alpinus significantly increased the mycelial biomass. The improvement of Sanghuangporus alpinus yield through liquid fermentation and optimizing the fermentation medium could fill the existing gap in the cultivation of Sanghuangporus alpinus, as well as provide valuable data for the large-scale production of S. alpinus.

Complex nitrogen sources from agro-industrial byproducts: impact on production, multi-stress tolerance, virulence, and quality of Beauveria bassiana blastospores.

Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.

Optimal nitrogen source for the recovery of phycoerythrin in discolored Rhodomonas sp.

Rhodomonas species are of interest as excellent aquaculture feed because of their ideal biochemical composition, especially their high protein content, resulting from the presence of intracellular phycoerythrin (PE). One of the most crucial issue with this species as a feed source is PE degradation under ambient nitrogen starvation, which leads to unpredictable growth defects and reduced nutritional value associated with cell discoloration. The aim of this study was to propose an optimal nitrogen source for the recovery of intracellular PE in discolored Rhodomonas sp. We supplied three different nitrogen sources, i.e., nitrate, ammonium, and urea, to PE-degraded cells and monitored changes in PE content and the expression of related genes. Supplementation with each nitrogen source increased cell density, with nitrate exhibiting the highest specific growth rate of 0.30 ± 0.02 day−1. The maximum PE content in each nitrogen group at 48 h after N supplementation was about 3.8 pg cell−1 with no major difference between groups. In contrast, the highest relative PE recovery rate of 5.73 ± 0.18-fold and the highest PE productivities of 0.32 ± 0.01 μg mL−1 h−1 were obtained in the nitrate group. Nitrogen transporter genes, including RhNrt2, RhAmt1, and RhDur3, were upregulated under nitrogen-starvation conditions, demonstrating the ability of this species to utilize each of the tested nitrogen sources. Furthermore, RhCpeb, which serves as a molecular indicator of PE biosynthesis, was significantly upregulated in all nitrogen-supplemented groups, with the strongest and fastest increase in expression in the nitrate group, emphasizing the potential of nitrate as the most favorable nitrogen source for PE recovery in this species. Our findings pave the way for informed strategies for the stable management and production of Rhodomonas species as high-protein feed in aquaculture.

Production of Lipopeptides from Bacillus velezensis BVQ121 and Their Application in Chitosan Antibacterial Coating.

The extracellular substance of Bacillus has antibacterial effects inhibiting multiple foodborne pathogens and plays important roles in food production. This study found one Bacillus velezensis BVQ121 strain producing antibacterial lipopeptides (BVAL). After optimization of the fermentation conditions, the BVAL yield was the highest at 1.316 ± 0.03 g/L in reality with the initial pH 6.0, temperature 31 °C, and shaker speed 238 rpm when the optimal nitrogen and carbon sources were used in Landy medium for fermentation. The antibacterial components were identified as iturin, surfactin, and fengycin by HPLC and MALDI-TOF-MS. The MIC was at 2 mg/mL and MBC was at 5 mg/mL. The 6% weight ratio of nanocellulose dosage in chitosan solution could improve the tensile length and strength of the film, and the antibacterial performance was enhanced by the addition of BVAL. The addition of BVAL had no effect on the color and ductility of the film and improved its antibacterial effect. The shelf life of pigeon eggs can be extended by more than 10 days to resist bacterial infections after coating with the chitosan-nanocellulose-BVAL film solution.

Microbial hyaluronic acid production in the 21 century: a roadmap toward high production, tailored molecular weight

Hyaluronic acid is a biopolymer that has gained attention from both researchers and the public since its discovery in 1934. In 2022, its global annual demand was 667 MT, with a market value of 9.4 billion dollars and an expected compound growth rate of 7.7% from 2024 and 2030. Such popularity lies in its many applications, which ranges from pharmaceutical to Tissue Engineering. Its molecular weight (MW) determines which application hyaluronic acid is better suited for: high MW (over 1 MDa) is used in medical applications such as osteoarthritis and ophthalmology, and low MW (less than 0.05 MDa) are suited for moisturizing cosmeceuticals. This makes hyaluronic acid molecular weight an important parameter for its production. The first industrial process was based on extraction from rooster combs. However, it shifted toward microbial production with Streptococcus zooepidemicus. Studies focus on improving its production and tailoring its molecular weight by accessing optimum temperature, pH, aeration, agitation, carbon, and nitrogen sources concentration and origin. his review aims to provide an overview of the current knowledge on the effects of metabolic and environmental factors in microbial hyaluronic acid production. The review shows that there has been extensive research in optimizing cultivation medium composition, temperature, pH, and aeration between 2018 and 2023, but further studies are required to optimize the metabolism of S. zooepidemicus towards maximum biopolymer production and molecular weight.

Identification the Pathogen Cause a New Apple Leaf Blight in China and Determination the Controlling Efficacy for Five Botanical Fungicides.

Alternaria leaf blight has recently been described as an emerging fungal disease of apple trees which is causing the significant damage in the apple-growing areas of Tianshui and Jingning, Gansu, China. In the present study, the pathogen species involved in apple leaf blight and its biological characteristics were identified, and the inhibitory activity of different botanical fungicides against the pathogen was evaluated in vitro. Four strains were isolated from the symptomatic areas of necrotic apple leaves, and initially healthy leaves showed similar symptoms to those observed in orchards after inoculation with the ABL2 isolate. The ABL2 isolate was identified as Alternaria tenuissima based on the morphological characteristics of its colonies, conidiophores, and conidia, and this was also confirmed by multi-gene sequence (ITS, OPA10-2, Alta-1, and endoPG) analysis and phylogenic analysis. The optimum temperature, pH, carbon source, and nitrogen source for the growth of A. tenuissima mycelia were 28 °C, 6-7, soluble starch, and soy flour, respectively. In addition, the botanical fungicide eugenol exhibited the highest inhibitory effect on the mycelial growth and conidia germination of A. tenuissima, and the median effective concentration (EC50) values were 0.826 and 0.755 μg/mL, respectively. The protective and curative efficacy of eugenol were 86.85% and 76.94% after inoculation in detached apple leaves at a concentration of 4 μg/mL. Our research provides new insights into the control of apple leaf blight disease by applying botanical fungicides.

Efficiency of thermostable purified laccase isolated from Physisporinus vitreus for azo dyes decolorization.

Laccases are versatile biocatalysts that are prominent for industrial purposes due to their extensive substrate specificity. Therefore, this research investigated producing laccase from Physisporinus vitreus via liquid fermentation. The results revealed that veratryl alcohol (4mM) was the most effective inducer 7500U/L. On the other hand, Zn ions inhibited laccase production. The optimum carbon and nitrogen sources were glucose and tryptone by 5200 and 3300 U/L, respectively. Moreover, solvents exhibited various impacts on the enzyme activity at three different solvent concentrations (5%, 10% and 20%), however, it showed a highest activity at 5% of the investigated solvent. Ferric ions inhibited the enzyme activity. In addition, the enzyme has a high ability to decolorize azo dyes when using syringaldehyde as a mediator. The purified laccase from Physisporinus vitreus is a promising substance to be used for industrial and environmental applications due to its stability under harsh conditions and efficiency in decolorization of dyes.

Production of single cell protein by fungi from different food wastes

AbstractSingle-cell protein (SCP) which is derived from agricultural waste has recently drawn increased interest as a substitute source of protein to improve both human and animal nutrition. In this study, pineapple, orange, banana, sugarcane, and garlic wastes were prepared as substrates for SCP production using fungi under a liquid fermentation system. The fermentation conditions (temperature, pH, and nitrogen sources) of the most promising fungal isolates were optimized for maximum SCP production. Results obtained showed that Aspergillus niger with pineapple waste after 10 days gave the highest protein content (9.79 ± 0.11 g/L), followed by Penicillium citrinum with orange waste after 8 days (9.41 ± 0.15 g/L) and Penicillium crustosum with banana waste after 6 days (7.75 ± 0.11 g/L).The optimum fermentation temperature, pH value, and nitrogen source for SCP production were recorded at 30 °C, pH 4.3, and ammonium sulphate with Aspergillus niger; at 30 °C, pH 5.0, and ammonium sulphate with Penicillium citrinum; and at 20 °C, pH 5.0, and ammonium sulphate with Penicillium crustosum. Based on proximate analysis of SCP produced, fat content ranged from 2.74 ± 0.08∼10.73 ± 0.1%, fibers from 4.8 ± 0.18∼9.45 ± 0.15%, carbohydrates from 14.1 ± 0.06∼20.81 ± 0.06%, ash from 4.05 ± 0.05∼16.1 ± 0.2%, total phenols 0.14 ± 0.03∼0.64 ± 0.04%, and total flavonoids 0.09 ± 0.01∼0.55 ± 0.15%. The amino acid profile of SCP showed that all essential amino acids were present in significant amounts. This study recorded some fungal species as SCP producers for the first time and provided a significant amount of protein. Briefly, fungal SCP is a great protein source and other essential nutrients that may be used in food products. Graphical Abstract

Development of a composite microbial agent beneficial to improve drought and salt tolerance of Glycyrrhiza uralensis Fisch.

Plant growth is enhanced by microbiological agents. In order to develop environment friendly composite microbial agent that can also improve the salt and drought tolerance of plants, the orthogonal experiment and response surface methodology were used to screen nutrients and fermentation conditions of composite microbial agent, and pot experiment was conducted to validate the application effect of optimized and complex microbial agent. Compatibility test showed that G2 (Bacillus cereus) and G5 (Bacillus pumilus) did not show any inhibitory effect on each other’s growth in nutrient agar, moreover, in both the growth promotion characteristics and the seed germination tests, G2+G5 showed a synergistic effect. The process optimization results showed that the optimal carbon and nitrogen sources for the medium nutrients was maltose and yeast extract, and the optimal carbon-nitrogen ratio was 5:1; the optimal fermentation conditions included initial pH at 5.17, inoculation amount of 2.28%, liquid volume of 105.96 mL(250 mL)−1, and incubation temperature at 30.06℃. Pot experiment showed that application with composite microbial agent was able to increase antioxidant enzyme activities, ascorbat, proline content, and reduce reactive oxygen species accumulation and membrane peroxidation of G. uralensis seedlings under salt-drought stress. In conclusion, the composite G2+G5 agent possessed remarkable synergistic effect for improve plant tolerance to drought combined with salt stress, suggesting a noticeble practical potential in agricultural practice, and it can be used to develop newtype environment friendly microbial fertilizer.

Xylitol fermentation characteristics with a newly isolated yeast Wickerhamomyces anomalus WA

Xylitol is an increasingly popular functional food additive, and the newly isolated yeast Wickerhamomyces anomalus WA has shown extensive substrate utilization capability, with the ability to grow on hexose (d-galactose, d-glucose, d-mannose, l-fructose, and d-sorbose) and pentose (d-xylose and l-arabinose) substrates, as well as high tolerance to xylose at concentrations of up to 300 g/L. Optimal xylitol fermentation conditions were achieved at 32 °C, 140 rpm, pH 5.0, and initial cell concentration OD600 of 2.0, with YP (yeast extract 10 g/L, peptone 20 g/L) as the optimal nitrogen source. Xylitol yield increased from 0.61 g/g to 0.91 g/g with an increase in initial substrate concentration from 20 g/L to 180 g/L. Additionally, 20 g/L glycerol was found to be the optimal co-substrate for xylitol fermentation, resulting in an increase in xylitol yield from 0.82 g/g to 0.94 g/g at 140 rpm, enabling complete conversion of xylose to xylitol.

Optimization of Some Culture Conditions and Medium Composition for the Production of Bacitracin from Lactobacillus helveticus DF

The objective of this study was to evaluate the effects of some culture conditions and components of the culture medium on the production of bacteriocin from Lactobacillus helveticus DF to get maximum bacteriocin yield. The results showed that the best culture conditions for maximum bacteriocin production were; pH 6, incubation temperature 37°C, incubation period 48 hours and the best culture medium MRS at anaerobic condition. Optimization of the medium ingredients was also investigated.The production of active antimicrobial peptide bacteriocin, active against Gram positive and Gram negative microorganisms including P.aeruginosa (B) and E. Feacalis (A), by L. helveticus DF isolated from feces of infants is influenced by complex nitrogen sources and carbon sources in the production medium. Medium components, especially pepton, beef extract and yeast extract, and their concentration contributed to increase in the production during the stationary phase. The Optimal nitrogen sources for their production were 1.5% , 2%, 2% (w/v) of pepton, beef extract and yeast extract respectively, accordingly, the present result evidenced that the increment in bacteriocin production was attributed with nitrogen source. Bacteriocin production by L. helveticus DF emphasized that, the higher bacteriocin yield was attained in the medium supplied with Tween 80 compared to medium without addition of tween 80, optimal concentration for their production 0.75%. Carbon source supplementation in culture media favored the maximum bacteriocin yield by L. helveticus DF, maximum bacteriocin yield when cultured in MRS supplemented with glucose and mannose (2%w/v). Bacteriocin production was affected differently by the presence of different concentrations of K2HPO4 or KH2PO4. Optimal bacteriocin production was recorded in the presence of 0.25% K2HPO4. The results of this study showed that the best production medium was named modified MRS medium which composed of 2% glucose, 2% mannose, 1.5% peptone, 2% yeast extract, 2% beef extract, 0.25% K2HPO4 and 0.75% tween 80, adjusted at pH 6 and incubated at 37°C for 48 hours (under anaerobic conditions) and with inoculum size of 4 % of cells number 1×109 cell/ml. After optimization, Bacteriocin activity was increase to 80 and 160 AU\ML against E. Feacalis (A) and P.aeruginosa (B) respectively.

EVALUATION OF WHEAT WITH DIFFERENT COATED CONTROLLED RELEASE UREA AND APPLICATION TIME IN SEMI-ARID CONDITIONS

Optimal nitrogen (N) application rate, source and timing are important to achieve high wheat yield. Overdose of N as basal dose promotes excessive vegetative growth and delays maturity, resulting in low N use efficiency (NUE) and crop yield. The current study was conducted for two years (2018-2019 and 2019-2020) to examine the influence of various N sources viz., common-urea, Zn-coated urea, neem-coated urea, and polymer-coated urea and their application methods (basal- and split-application) on the growth, physiology, yield, and related traits in wheat under semi-arid conditions. Results showed that N sources and application methods significantly affected the growth, physiological and yield-related traits; neem-coated urea applied in splits remained the most effective source for the observed traits, followed by Zn-coated, polymer-coated, and common urea. Compared with common urea, neem-coated urea significantly increased chlorophyll (Chl) and carotenoid contents under basal and split application. Neem-coated urea also recorded higher biological and grain yields than other
 treatments which were associated with higher values of yield-related traits including the number of productive tillers, number of spikelets, and number of grains per spike. For N application methods, split application significantly improved the plant height, Chl pigments, yield- and yield-related traits compared with the basal application. In conclusion, neem-coated urea application as a split application performed well followed by Zncoated and polymer-coated urea in improving the growth and overall yield.

Optimization of Carbon and Nitrogen Source to Enhance Antibacterial Activity from a Sponge-derived Bacillus tequilensis

In our endeavor to find antibacterial from marine bacteria, we screened the microbiota from a Lithistid sponge, collected from Seribu Island, Jakarta. One of the promising strains was K 2.4.2. Identification of the strain using 16S rRNA Sanger sequencing resulted a sequence similarity of 100% to Bacillus tequilensis. Response surface methodology was applied to optimize the culture conditions for enhancing antibacterial activity of the strain. The optimization was carried out using Box-Behnken design experiment to determine the optimum carbon and nitrogen sources in order to produce maximum antibacterial activity. The optimum media with high antibacterial activity was marine broth with the addition of carbon and nitrogen concentration source of sucrose 2.15 % and peptone 1.08%, respectively. In addition, the optimum temperature was 31.18oC. The antibacterial activity response was predicted using a statistical model and compared to the activity in the experiment. The difference between the model and the laboratory experiment was less than 5% which showed a good accuracy. The results of this study once again showed that optimization method effectively reduced time, chemicals, and energy.

Biodegradation of Cholesterol by Enterococcus faecium YY01.

Cholesterol (CHOL) is one of the risk factors causing the blockage of the arterial wall, atherosclerosis, coronary heart disease, and other serious cardiovascular diseases. Here, a promising bacterial strain for biodegrading CHOL was successfully isolated from the gut of healthy individuals and identified as Enterococcus faecium YY01 with an analysis of the 16S rDNA sequence. An initial CHOL of 1.0 g/L was reduced to 0.5 g/L in 5 days, and glucose and beef extract were found to be optimal carbon and nitrogen sources for the rapid growth of YY01, respectively. To gain further insight into the mechanisms underlying CHOL biodegradation, the draft genome of YY01 was sequenced using Illumina HiSeq. Choloylglycine hydrolase, acyltransferase, and alkyl sulfatase was encoded by gene0586, gene1890, and gene2442, which play crucial roles in converting 3α, 7α, 12α-trihydroxy-5β-choranic acid to choline-CoA and then choline-CoA to bile acid. Notably, choloylglycine hydrolase was closely related to the biosynthesis of both primary and secondary bile acid. The findings of this study provide valuable insights into the metabolism pathway of CHOL biodegradation by YY01 and offer a potential avenue for the development of bacterioactive drugs against hypercholesterolemia.