Alternative Nitrogen Sources Research Articles

Improving bermudagrass in the Southeastern United States with alfalfa as an alternative nitrogen source in grazing systems

AbstractBackgroundBermudagrass (Cynodon spp.) is one of the most common perennial warm‐season forages grown in the Southeastern United States. The incorporation of alfalfa (Medicago sativa) into bermudagrass pastures could serve as an alternative source of nitrogen (N) while also improving the nutritive value of the forage base.MethodsA 2‐year grazing evaluation arranged in a randomized complete block design was conducted from May to September 2018 (Year 1) and May–August 2019 (Year 2) in Tifton, GA, USA. The objective was to compare the production of alfalfa–bermudagrass mixed pastures (BGA) with bermudagrass monoculture pastures with (BGN) or without (BG) the application of synthetic nitrogen on forage production and stocker cattle performance.ResultsDifferences were observed for average daily gain (p = 0.10), gain per hectare (p = 0.02) and stocking rate (p = 0.01), in that BGA was greatest compared to BGN and BG, which did not differ from each other. Furthermore, BGA had increased forage crude protein (p = 0.01) and total digestible nutrients (p = 0.01) compared to BGN and BG. Finally, BGA provided the greatest economic return per hectare compared to BG or BGN.ConclusionsThese data illustrate improved animal performance and forage nutritive value using alfalfa–bermudagrass systems and offer a viable option for producers seeking alternatives to synthetic N sources for bermudagrass pastures in the Southeastern United States.

Urea is a drop-in nitrogen source alternative to ammonium sulphate in Yarrowia lipolytica.

Media components, including the nitrogen source, are significant cost factors in cultivation processes. The nitrogen source also influences cell behavior and production performance. Ammonium sulfate is a widely used nitrogen source for microorganisms' cultivation. Urea is a sustainable and cheap alternative nitrogen source. We investigated the influence of urea as a nitrogen source compared to ammonium sulfate by cultivating phenotypically different Yarrowia lipolytica strains in chemostats under carbon or nitrogen limitation. We found no significant coherent changes in growth and lipid production. RNA sequencing revealed no significant concerted changes in the transcriptome. The genes involved in urea uptake and degradation are not upregulated on a transcriptional level. Our findings support urea usage, indicating that previous metabolic engineering efforts where ammonium sulfate was used are likely translatable to the usage of urea and can ease the way for urea as a cheap and sustainable nitrogen source in more applications.

Alternative Nitrogen Source for Producing Crude Extracted IAA and Suitable Method for Enhancing the Germination of Jerusalem Artichoke

Alternative Nitrogen Source for Producing Crude Extracted IAA and Suitable Method for Enhancing the Germination of Jerusalem Artichoke

Plant Proteins as an Alternative Nitrogen Source for Chiral Purity L-Lactic Acid Fermentation from Lignocellulose Feedstock

High optical purity lactic acid is in high demand as the precursor for synthesizing polylactic acid (PLA). The costs of expensive carbohydrates and nitrogen source materials accounts for a large portion of the production costs in lactic homo-fermentation. The use of lignocellulosic biomass for lactic acid production reduces the cost of the carbohydrate feedstock, but the cost of nitrogen sources is a big challenge when considering the high prices of general nitrogen sources. Low-cost nitrogen materials are vulnerable to being contaminated by exogenous mixed L-lactic acid and D-lactic acid; thus, their feasibility as nitrogen sources for the production of optically pure lactic acid products is hindered. The available reports focus on cost reduction using agro-industrial byproducts as nutrient sources, with these presenting fewer concerns on the effect of the optical purity of lactic acid-product monomers for polymerization. In this study, commonly used low-cost nutrient sources were characterized and screened for high optical purity L-lactic acid fermentation. Corn steep liquor (CSL), a widely used and cheap nutrient for lactic acid fermentation, was found not to be suitable because of its high content of mixed D-/L-lactic acids (up to 20%, w/w). On the other hand, cottonseed meal was found to be completely free of mixed L-/D-lactic acids. Therefore, the cottonseed meal was hydrolyzed with dilute sulfuric acid and used as a nitrogen source for L-lactic acid fermentation using lignocellulose feedstock as a substitution for yeast extract and peptone. The results showed that the final L-lactic acid titer reached 96.5 ± 0.2 g/L from 25% (w/w)-solids loaded pretreated and biodetoxified wheat straw with a yield of 0.31 g/g feedstock and an optical purity of 99.7%. The techno-economic evaluation indicated that the cost of the cottonseed meal was only USD 0.193/kg of lactic acid product, and the minimum lactic acid selling price (MLSP) was USD 0.813/kg of lactic acid product, which was only 25.1% compared to the use of yeast extract and peptone as the nutrients. Cellulosic L-lactic acid production using cottonseed meal as a complex nutrient source showed competitive performance when compared to starch feedstock from food crops.

The impact of alternative nitrogen sources on the growth and viability of Lactobacillus delbrueckii ssp. bulgaricus.

In this study, we developed and optimized a growth medium using various nitrogen sources for the cultivation of Lactobacillus delbrueckii ssp. bulgaricus, a probiotic and essential dairy starter culture. The composition of de Man, Rogosa, and Sharpe (MRS) culture medium was modified, and the nitrogen content was replaced by alternative nitrogen sources X-Seed Nucleo Max, X-Seed KAT, and X-Seed Carbo Max (Ohly GmbH) in various blends of 5 and 10 g/L. Results showed that bacterial growth was significantly higher when the nitrogen source blend of 10 g/L of KAT and 10 g/L of Carbo Max [KCMax (10/10)] was used. The optical densities of the Lb. bulgaricus strains were significantly higher in the KCMax (10/10) medium than in the MRS medium. There was no significance in bacterial counts for both the MRS and the KCMax (10/10) medium, and all bacterial counts were estimated at 8 log cfu/mL. The buffering capacity of the KCMax (10/10) medium was also tested and supplemented with l-histidine and was significantly higher than that of the MRS control medium. KCMax (10/10) also supported the freeze-stability and viability of the Lb.bulgaricus cells during freezing and freeze-drying operations. Our results suggest that the alternative nitrogen sources X-Seed Nucleo Max, X-Seed KAT and X-Seed Carbo Max can substantially support the growth of lactic acid bacteria as demonstrated with Lb. bulgaricus. These alternative nitrogen sources could thus be recommended for lactic acid bacteria fermentation and for the cultivation of dairy starter cultures.

The potential impact of replacing nitrate with ammonium hydroxide in microalgae production on the biomass productivity and CO2 utilization efficiency

Ammonium hydroxide has many advantages as a CO 2 absorbent compared with other amine solutions in Carbon Capture, Utilization and Storage. In this work, the use of ammonium hydroxide was suggested to replace the nitrate as an alternative nitrogen source and to enhance the CO 2 utilization and biomass production during microalgae cultivation. Abiotic absorption experiments showed that the CO 2 absorption capacity of culture medium increased with the increase of ammonium hydroxide concentration, and it kept consistent with different kind of CO 2 absorbents. Consumption curves for sodium nitrate and ammonium hydroxide were built from batch cultivation experimental data and it was found that the microalgal cells had faster growth rates when these nutrients concentrations were kept at low levels (2 mmol/L and 4 mmol/L, respectively). In the fed-batch cultures under both indoor and outdoor operations, the maximum biomass concentration and carbon utilization efficiency using ammonium hydroxide as a nitrogen source was much higher than that of using sodium nitrate as a nitrogen source. By using pH-regulated CO 2 supplementation, the pH of the microalgae culture medium was maintained within the neutral or slightly alkaline range. Thus, the volatilization of ammonium hydroxide was negligible. These results indicated that replacing nitrate with ammonium hydroxide could be a promising approach to increase CO 2 utilization efficiency and to reduce production costs in microalgae cultivation. • Replacing sodium nitrate with ammonium hydroxide as the nitrogen source was first proposed in microalgal cultivation. • Biomass concentration and carbon utilization efficiency using ammonium hydroxide as nitrogen sources were achieved by 2.35 g/L, and 114.93%. • A 32.8 % increase in the biomass productivity using ammonium hydroxide compared to that of sodium nitrate under outdoor conditions. • Ammonium hydroxide could be a cheaper source of nitrogen that can enhance CO 2 utilization by microalgae.

Nitrogen source: an effective component for the growth and viability of Lactobacillus delbrueckii subsp. bulgaricus

AbstractIn this study, we developed and optimized a growth media by evaluating various nitrogen sources for the cultivation of Lactobacillus bulgaricus, a probiotic and an important dairy starter culture. We modified the composition of deMan, Rogosa and Sharpe (MRS) culture media and substituted the nitrogen content with alternative nitrogen sources X-Seed KAT, X-Seed Carbo Max and X-Seed Nucleo Max in various blends of 5 g/l and 10 g/l respectively. Results showed that bacterial growth was significantly higher when the nitrogen source blend KCMax (10/10) was used. The optical density (OD610 nm) of the Lactobacillus bulgaricus strains were higher (1.34 and 1.79) in the KCMax (10/10) medium than in the MRS medium (0.89 and 1.42) (P < 0.05). There was no significant difference in the bacterial counts for both the MRS medium and the KCMax (10/10) medium, and all bacterial counts were estimated at 8 log CFU/ml. The buffering capacity of KCMax (10/10) was also tested and supplemented with l-histidine and was significantly different (P < 0.05) than that of the MRS control medium. Calcium supplemented in the KCMax (10/10) also served as a cryoprotectant for the cells during freezing and freeze-drying. Bacterial counts of the recovered calcium-treated freeze-dried cells were statistically significant (P < 0.05). We hypothesized that alternative nitrogen sources such as selected yeast extracts from the X-Seed brand of complex nitrogen sources could efficiently support the viability of Lb. bulgaricus. Our results thus suggested the growth of Lb. bulgaricus was efficiently supported by the X-Seed KAT, X-Seed Nucleo Max and X-Seed Carbo Max nitrogen sources. Consequently, these alternative nitrogen sources could potentially be recommended for dairy starter culture fermentations.

Nitrogen Use Efficiency and Maize Performance through Application of Urea Stable and Urea in Highland Nitisol of Midakegn and Toke Kutaye Districts

The field experiment was conducted in 2018 and 2019 cropping season to determine the effects of urea stable and urea on nitrogen use efficiency and maize performance in highland Nitisol of Midakegn and Toke Kutaye districts. The experiment was laid out in randomized complete block design with three replications. Nine treatments of urea stable and urea with different application times was used. Application of different nitrogen rate from urea stable and urea were significantly (P < 0.05) influenced mean plant height, leaf area index, dry biomass, grain yield, thousand seed weight and harvest index of maize crop. Significantly higher mean leaf area index (4.1), thousand seed weight (357 g), dry biomass (16472 kg ha-1) and grain yield (5475 kg ha-1) were recorded from split application of 138 kg N ha-1 from urea stable whereas higher mean plant height was recorded from split application 138 kg N ha-1 from urea. Application of nitrogen rate were also affected nitrogen uptake and agronomic nitrogen efficiency of maize. Mean agronomic nitrogen efficiency showed decreasing trend with increasing of nitrogen fertilizer application. Significantly higher and lower value of agronomic nitrogen efficiency were obtained from split application of 46 kg N ha-1 from urea stable and 138 kg N ha-1 from urea stable applied at planting. Agronomic parameters and nitrogen uptake were only influenced by nitrogen rate indicating slow releasing of nitrogen from urea stable and confirmed this form fertilizer reduce N loss. Both urea stable and urea sources of nitrogen gave similar yield at the same rates. Therefore, urea stable could be used as alternative nitrogen source in addition to urea if the cost and accessibility of this fertilizer is the same for the area.

Optimization of culture medium and scale-up production of astaxanthin using corn steep liquor as substrate by response surface methodology

Astaxanthin is a natural carotenoid with strong antioxidant activity. In this paper, the effects of carbon source, corn steep liquor, distiller grains, and initial pH on the growth and astaxanthin production of Phaffia rhodozyma D3 were evaluated. The optimal medium composition was 32 g/L glucose, 12 g/L corn steep liquor as nitrogen source, and the initial pH was 6.7. Phaffia rhodozyma D3 was cultured in a shake flask under these optimized conditions, the biomass was 6.47 g/L, the astaxanthin/OD475 was 15.16, and the astaxanthin content was 1.41 mg/g. The astaxanthin content was further increased to 4.70 mg/g by the combination of TiO2 stimulation and the expanding cultivation of P. rhodozyma D3 in a 5 L fermenter, which was 2.81 times that of the control group. Expanding fermentation implies the possibility of large-scale production in the astaxanthin industry. Corn steep liquor was used as an alternative nitrogen source to culture P. rhodozyma D3, which could both reduce the production cost of astaxanthin and increased the by-products utilization rate.

Assessment of vine shoots and surplus grape must for succinic acid bioproduction.

Vine shoots and surplus grape must were assessed as feedstocks for succinic acid production with Actinobacillus succinogenes and Basfia succiniproducens. After acidic and enzymatic hydrolysis, vine shoots released 35-40g/L total sugars. Both bacterial species produced 18-21g/L succinic acid from this hydrolysate in 120h. Regarding grape must fermentation, A. succinogenes clearly outperformed B. succiniproducens. Yeast extract (a source of organic nitrogen and vitamins) was the only additional nutrient needed by A. succinogenes to grow on grape must. Under mathematically optimized conditions (145.7g/L initial sugars and 24.9g/L yeast extract), A. succinogenes generated 88.9 ± 1.4g/L succinic acid in 96h, reaching a succinic acid yield of 0.66 ± 0.01g/g and a sugar consumption of 96.64 ± 0.30%. Substrate inhibition was not observed in grape musts with 125-150g/L initial sugars, provided that an adequate amount of yeast extract was available for bacteria. Alternative nitrogen sources to yeast extract (red wine lees, white wine lees, urea, NH4Cl, and choline chloride) were not suitable for A. succinogenes in grape must. KEY POINTS: • Vine shoots and surplus grape must were assessed for succinic acid bioproduction. • Succinic acid bioproduction was 21g/L with vine shoots and 89g/L with grape must. • Fermentation was efficient at high sugar loads if organic N supply was adequate.

Exaggerated trans-membrane charge of ammonium transporters in nutrient-poor marine environments.

Transporter proteins are a vital interface between cells and their environment. In nutrient-limited environments, microbes with transporters that are effective at bringing substrates into their cells will gain a competitive advantage over variants with reduced transport function. Microbial ammonium transporters (Amt) bring ammonium into the cytoplasm from the surrounding periplasm space, but diagnosing Amt adaptations to low nutrient environments solely from sequence data has been elusive. Here, we report altered Amt sequence amino acid distribution from deep marine samples compared to variants sampled from shallow water in two important microbial lineages of the marine water column community-Marine Group I Archaea (Thermoproteota) and the uncultivated gammaproteobacterial lineage SAR86. This pattern indicates an evolutionary pressure towards an increasing dipole in Amt for these clades in deep ocean environments and is predicted to generate stronger electric fields facilitating ammonium acquisition. This pattern of increasing dipole charge with depth was not observed in lineages capable of accessing alternative nitrogen sources, including the abundant alphaproteobacterial clade SAR11. We speculate that competition for ammonium in the deep ocean drives transporter sequence evolution. The low concentration of ammonium in the deep ocean is therefore likely due to rapid uptake by Amts concurrent with decreasing nutrient flux.

Cassava Leaves as an Alternative Nitrogen Source for Ethanol Fermentation

Cassava Leaves as an Alternative Nitrogen Source for Ethanol Fermentation

Ingestion of Diazotrophs Makes Corals More Resistant to Heat Stress.

Over the past decade, coral bleaching events have continued to recur and intensify. During bleaching, corals expel millions of their symbionts, depriving the host from its main food source. One mechanism used by corals to resist bleaching consists in exploiting food sources other than autotrophy. Among the food sources available in the reefs, dinitrogen (N2)-fixing prokaryotes or planktonic diazotrophs (hereafter called ‘PD’) have the particularity to reduce atmospheric dinitrogen (N2) and release part of this nitrogen (diazotroph-derived nitrogen or DDN) in bioavailable form. Here, we submitted coral colonies of Stylophora pistillata, fed or not with planktonic diazotrophs, to a temperature stress of up to 31 ± 0.5 °C and measured their physiological responses (photosynthetic efficiency, symbiont density, and growth rates). Heat-unfed colonies died 8 days after the heat stress while heat-PD-fed corals remained alive after 10 days of heat stress. The supply of PD allowed corals to maintain minimal chlorophyll concentration and symbiont density, sustaining photosynthetic efficiency and stimulating coral growth of up to 48% compared to unfed ones. By providing an alternative source of bioavailable nitrogen and carbon, this specific planktonic diazotroph feeding may have a profound potential for coral bleaching recovery.

Production and nutritional value of Mombaça grass with application of whey as an alternative nitrogen source

Whey is a waste generated in large quantities in dairy industries, and its use in agriculture as a source of nutrients can be an appropriate destination. Thus, the objective of this study was to evaluate the effect of whey as a nitrogen source for production and nutritional value of Mombaça grass. The experiment was conducted in pots, in a randomized blocks factorial scheme with four replicates. The treatments consisted of 5 doses of whey (0; 100; 200; 300 and 400 mg dm-3 N) associated with 3 doses de N-urea (0; 100 and 200 mg dm-3 N). Portions of 7 dm3 soil were incubated with lime and phosphate fertilizer and, 15 days before the end of incubation, the doses of whey were applied. After incubation, sowing followed by thinning (four plants/pot) were carried out, and the doses of N-urea were divided into 3 applications. Three grass cuts were made and, after the first cut, the treatments doses of whey and N-urea were reapplied. Whey fertilization increased the number of tillers, shoot dry matter production and crude protein of Mombaça grass, and the increases obtained varied as a funcion of the grass cycle and the N-ureea dose. The agronomic efficiency index of whey with N source in relation to urea was, on average, 69%. The whey increases production and improves the nutritional value of Mombaça grass, being an efficient alternative source of N for the forage.

Algal Diversity in Paddy Fields of Bhor and Velhe Talukas of Pune District Maharashtra State, India

A variety of Algae occurs in the water and soil of rice field ecosystems. These algae include green algae, desmids, diatoms and blue green algae with respect to their requirements like light, water, high temperature and nutrient availability. Paddy field ecosystem provides an environment favorable for the growth of BGA (Blue Green Algae). Algal flora is an idea of utilizing it as biofertilizer as an alternative or supplementary source of nitrogen, for rice is a potential biological system under low-cost rice production technology. The resulting nitrogen fertility by algal application has permitted moderate but constant productivity in fields having no application of Nitrogen fertilizer (Kannaiyan, 1993). In this respect, algal flora from rice fields from Bhor and Velhe has been documented with proper identification. During the survey, more than 20 algae were found.

Growth kinetics and quantification of carbohydrate, protein, lipids, and chlorophyll of Spirulina platensis under aqueous conditions using different carbon and nitrogen sources

This study evaluated different carbon and nitrogen sources on the growth and production of carbohydrates, protein, lipids, and chlorophyll of Spirulina platensis LEB-52 through an easy successive methodology under aqueous conditions. Spirulina platensis was cultivated at 120 rpm and light intensity of 156 µmol m−2 s−1 in a 500 mL Erlenmeyer flask with a working volume of 250 mL, using Zarrouk’s medium. The biomass, carbohydrate, and protein production together with the specific growth rate did not show a significant difference between NaHCO3 and Na2CO3. The salts of urea and ammonium are not an alternative nitrogen sources of low cost for Spirulina platensis cultivation. From the experimental results obtained in this study, a successful estimate of carbohydrate, protein, lipids, and chlorophyll content inside Spirulina platensis was achieved without use advanced analytical techniques, allowing saves resources and time. This method can be extrapolated to other microorganisms and cultivation regimens.

Pigment production by Scenedesmus dimorphus using different low‐cost and alternative culture media

AbstractBACKGROUNDThis study investigated the feasibility of producing pigments from Scenedesmus dimorphus using different low‐cost synthetic and alternative media. Thus the influence of nitrogen and phosphorus deficiency, different nitrogen sources and alternative culture media (wheat bran, garlic powder, wheat bran supplemented with garlic powder) on pigment and biomass production was evaluated.RESULTSAmong the three sources of nitrogen studied (ammonium sulfate, urea and sodium nitrate), urea was the cheapest efficient alternative source of nitrogen for pigment production, especially total chlorophylls (67.38 μg L−1 d−1), by this strain, without strongly affecting biomass yield. Phosphorus deficiency had no negative effect on biomass production, but improved the production of zeaxanthin and chlorophyll b by13.1% and 26.8%, respectively, compared to control. Compared to BG‐11 medium, the alternative garlic powder medium increased the biomass yield of S. dimorphus by 5.2 times, improved the productivity of xanthophylls and contributed to the accumulation of β‐carotene.Wheat bran medium was found to be efficient as a zero‐cost culture medium for the production of pigments, where S. dimorphus accumulated twice the total pigment concentration of the control, with high β‐carotene productivity (38.58 ± 11.94 μg L−1 d−1). The addition of garlic powder to wheat bran increased the biomass (3.14 g L−1) and pigment productivity (216.86 ± 2.06 μg L−1 d−1) by 28.5 and 1.4 times, respectively, but inhibited zeaxanthin biosynthesis. This alternative medium reduced biomass and pigment production costs by 99.80% and 96.21%, respectively.CONCLUSIONWheat bran supplemented with garlic powder showed good application potential for the industrial production of biomass and pigments from S. dimorphus in open cultivation systems where garlic powder might be used simultaneously for biomass and pigment accumulation, and for biological contamination control. © 2021 Society of Chemical Industry (SCI).

Expression of bik cluster and production of bikaverin by Fusarium oxysporum f. sp. lycopersici grown using two alternate nitrogen sources.

The genus Fusarium can be utilized to produce a great variety of secondary metabolites under specific culture conditions, including pigments of increasing biotechnological interest, such as bikaverin. Such pigments are important due to the biological properties they possess, including antitumor and antibiotic activities, among others. In Fusarium fujikuroi, bik1-bik6 have been identified as the genes that are responsible for the synthesis of bikaverin. Therefore, in this study, we screened for the presence of bik genes and examined changes in mRNA levels of the bik genes under the influence of NH4NO3 (0.024, 0.048, 0.50, 1.0, and 4.60g L-1) and NH4Cl (0.50 and 1.0g L-1) as nitrogen sources for the phytopathogen Fusarium oxysporum f. sp. lycopersici. Our results indicated the presence of at least six bik (bik1-bik6) genes and showed increased mRNA levels for bik4, bik5, and bik6 in conditions where NH4NO3 was used at pH 3.0. The characteristic coloration of bikaverin was obtained in 10 out of 16 culture conditions, except when the fungus was grown with higher concentrations of NH4NO3 (1.0 and 4.60g L-1). The pigment was chloroform-extracted from the culture conditions of NH4NO3 (0.024, 0.048, and 0.50g L-1) and NH4Cl (0.50 and 1.0g L-1) with 3 and 9days of incubation. Analysis via visible spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry were used for the identification of bikaverin.

Novel Glutamate-Putrescine Ligase Activity in Haloferax mediterranei: A New Function for glnA-2 Gene.

The genome of the halophilic archaea Haloferax mediterranei contains three ORFs that show homology with glutamine synthetase (GS) (glnA-1, glnA-2, and glnA-3). Previous studies have focused on the role of GlnA-1, suggesting that proteins GlnA-2 and GlnA-3 could play a different role to that of GS. Glutamine synthetase (EC 6.3.1.2) belongs to the class of ligases, including 20 subclasses of other different enzymes, such as aspartate–ammonia ligase (EC 6.3.1.1), glutamate–ethylamine ligase (EC 6.3.1.6), and glutamate–putrescine ligase (EC 6.3.1.11). The reaction catalyzed by glutamate–putrescine ligase is comparable to the reaction catalyzed by glutamine synthetase (GS). Both enzymes can bind a glutamate molecule to an amino group: ammonium (GS) or putrescine (glutamate–putrescine ligase). In addition, they present the characteristic catalytic domain of GS, showing significant similarities in their structure. Although these proteins are annotated as GS, the bioinformatics and experimental results obtained in this work indicate that the GlnA-2 protein (HFX_1688) is a glutamate–putrescine ligase, involved in polyamine catabolism. The most significant results are those related to glutamate–putrescine ligase’s activity and the analysis of the transcriptional and translational expression of the glnA-2 gene in the presence of different nitrogen sources. This work confirms a new metabolic pathway in the Archaea domain which extends the knowledge regarding the utilization of alternative nitrogen sources in this domain.

The histone chaperone HIR maintains chromatin states to control nitrogen assimilation and fungal virulence.

SUMMARYAdaptation to changing environments and immune evasion is pivotal for fitness of pathogens. Yet, the underlying mechanisms remain largely unknown. Adaptation is governed by dynamic transcriptional re-programming, which is tightly connected to chromatin architecture. Here, we report a pivotal role for the HIR histone chaperone complex in modulating virulence of the human fungal pathogen Candida albicans. Genetic ablation of HIR function alters chromatin accessibility linked to aberrant transcriptional responses to protein as nitrogen source. This accelerates metabolic adaptation and increases the release of extracellular proteases, which enables scavenging of alternative nitrogen sources. Furthermore, HIR controls fungal virulence, as HIR1 deletion leads to differential recognition by immune cells and hypervirulence in a mouse model of systemic infection. This work provides mechanistic insights into chromatin-coupled regulatory mechanisms that fine-tune pathogen gene expression and virulence. Furthermore, the data point toward the requirement of refined screening approaches to exploit chromatin modifications as antifungal strategies.