Citric Acid Production Research Articles

Pomegranate peel waste: a new substrate for citric acid production by Aspergillus niger in solid-state fermentation under non-aseptic conditions.

Citric acid production from dried and non-dried pomegranate peel wastes by the fungus Aspergillus niger B60 in solid-state fermentation (SSF) under non-aseptic conditions was investigated. The maximum amount of citric acid (278.5g/kg dry peel) was achieved using dried (at 45°C for 48h) pulverized pomegranate peels with moisture content 75% and initial pH8.0, after 8days of fermentation at 25°C. Under the same fermentation conditions, a higher amount of citric acid (306.8g/kg dry peel) was observed during SSF of non-dried peels as a substrate. The addition of methanol as an inducer at a concentration of 3% (w/w) into the dried and non-dried pomegranate peel wastes increased the amount of citric acid to 300.7 and 351.5g/kg dry peel, respectively. The non-dried pomegranate peel waste in SSF under non-aseptic conditions is a cheap and useful substrate for the commercial production of citric acid with low energy cost. The utilization of inexpensive agro-industrial wastes through SSF can contribute to achieve industrially feasible and environmentally sustainable bio-production of citric acid.

Comparison of Addition Mold and Yeast Inoculants on the Production of Citric Acid in Liquid and Solid Media from Sorghum

The aim of the study was to determine the production of citric acid in liquid and solid media made from the juice and bagasse of sorghum plant. Sorghum has a great potential to be utilized as fermentation substrate for production of citric acid. The production of citric acid by fermentation is influenced by several factors including the type of media and used microorganisms. Fermentation to produce citric acid can be done by using mold as well as yeast. In this study, the mold isolates were Beauveria bassiana and Paelomyces lilacinus, while the yeast isolates were Candida utilis and Candida lessepsii. The fungal fermentations were conducted in two phases of medium, liquid and solid. Three formulas were prepared for liquid fermentation, namely sorghum juice only, sorghum juice supplemented with NH4NO3 and micronutrients, and sorghum juice supplemented with asparagine and micronutrients. Two formulas were prepared for solid fermentation, sulfuric acid hydrolyzed sorghum bagasse and non-hydrolyzed sorghum bagasse. The results showed that citric acid yield in solid fermentation is lower than liquid fermentation. For all formulas, the citric acid formation through liquid fermentation was higher in yeast than in molds. On the other hand, for solid fermentation, citric acid production was higher in hydrolyzed media than non-hydrolyzed media, except for yeast Candida lessepsii.

The effects of external Mn2+ concentration on hyphal morphology and citric acid production are mediated primarily by the NRAMP-family transporter DmtA in Aspergillus niger

BackgroundCitric acid, a commodity product of industrial biotechnology, is produced by fermentation of the filamentous fungus Aspergillus niger. A requirement for high-yield citric acid production is keeping the concentration of Mn2+ ions in the medium at or below 5 µg L−1. Understanding manganese metabolism in A. niger is therefore of critical importance to citric acid production. To this end, we investigated transport of Mn2+ ions in A. niger NRRL2270.Resultswe identified an A. niger gene (dmtA; NRRL3_07789), predicted to encode a transmembrane protein, with high sequence identity to the yeast manganese transporters Smf1p and Smf2p. Deletion of dmtA in A. niger eliminated the intake of Mn2+ at low (5 µg L−1) external Mn2+ concentration, and reduced the intake of Mn2+ at high (> 100 µg L−1) external Mn2+ concentration. Compared to the parent strain, overexpression of dmtA increased Mn2+ intake at both low and high external Mn2+ concentrations. Cultivation of the parent strain under Mn2+ ions limitation conditions (5 µg L−1) reduced germination and led to the formation of stubby, swollen hyphae that formed compact pellets. Deletion of dmtA caused defects in germination and hyphal morphology even in the presence of 100 µg L−1 Mn2+, while overexpression of dmtA led to enhanced germination and normal hyphal morphology at limiting Mn2+ concentration. Growth of both the parent and the deletion strains under citric acid producing conditions resulted in molar yields (Yp/s) of citric acid of > 0.8, although the deletion strain produced ~ 30% less biomass. This yield was reduced only by 20% in the presence of 100 µg L−1 Mn2+, whereas production by the parent strain was reduced by 60%. The Yp/s of the overexpressing strain was 17% of that of the parent strain, irrespective of the concentrations of external Mn2+.ConclusionsOur results demonstrate that dmtA is physiologically important in the transport of Mn2+ ions in A. niger, and manipulation of its expression modulates citric acid overflow.

Application of Stable Isotope Tracing to Elucidate Metabolic Dynamics During Yarrowia lipolytica α-Ionone Fermentation.

SummaryTargeted metabolite analysis in combination with 13C-tracing is a convenient strategy to determine pathway activity in biological systems; however, metabolite analysis is limited by challenges in separating and detecting pathway intermediates with current chromatographic methods. Here, a hydrophilic interaction chromatography tandem mass spectrometry approach was developed for improved metabolite separation, isotopologue analysis, and quantification. The physiological responses of a Yarrowia lipolytica strain engineered to produce ∼400 mg/L α-ionone and temporal changes in metabolism were quantified (e.g., mevalonate secretion, then uptake) indicating bottleneck shifts in the engineered pathway over the course of fermentation. Dynamic labeling results indicated limited tricarboxylic acid cycle label incorporation and, combined with a measurable ATP shortage during the high ionone production phase, suggested that electron transport and oxidative phosphorylation may limit energy supply and strain performance. The results provide insights into terpenoid pathway metabolic dynamics of non-model yeasts and offer guidelines for sensor development and modular engineering.

Diseño de un proceso de producción de ácido cítrico por simulación computacional.

El diseño de un proceso de producción de ácido cítrico a partir de la fermentación con Aspergillus Niger por simulación computacional, se realizó con el uso del software SuperPro Designer, los parámetros de diseño se establecieron en base a estudios previos, mismos que se ingresaron a la plataforma de cálculo, posteriormente los resultados obtenidos en el diseño se analizaron técnica y económicamente, lo que permitió determinar una cantidad de producción de ácido cítrico de 6 914. 69 ton/año, al usar precios FOB (Free on board) se tiene una inversión total de $ 31 460 000 junto a un VAN (Valor actual neto) de $165 000 y un TIR (Tasa interna de retorno) del 8.05%, lo que indica que el proyecto se puede llevar a cabo y resulta rentable en un tiempo de retribución de 8 años. El proceso consta de dos etapas: fermentación y aislamiento, que deben realizarse bajo las condiciones de operación (T= 25ºC y P= 1 atmósfera en la mayoría de las operaciones) y las condiciones óptimas de fermentación para el Aspergillus niger (T= 35ºC, pH= 5.8 y P= 1 atmósfera) que son adecuadas para obtener un producto de calidad que pueda ofertarse en el mercado nacional como internacional. Finalmente, se comprueba que el uso de software permite desarrollar estudios técnicos sin la necesidad de recurrir a largos períodos de tiempo con análisis experimentales en laboratorio, es decir, nos ahorra: tiempo, costos de pre-diseño y errores.

Isolation methods of high glycosidase-producing mutants of Aspergillus luchuensis and its mutated genes

High glycosidase-producing strains of Aspergillus luchuensis were isolated from 2-deoxyglucose (2-DG) resistant mutants. α-Amylase, exo-α-1,4-glucosidase, β-glucosidase and β-xylosidase activity in the mutants was ~3, ~2, ~4 and ~2.5 times higher than the parental strain RIB2604 on koji-making conditions, respectively. Citric acid production and mycelia growth of the mutants, however, approximately halved to that of the parent. Compared to the parent, the alcohol yield from rice and sweet potato shochu mash of the mutant increased ~5.7% and 3.0%, respectively. The mutant strains showed significantly low glucose assimilability despite the fructose one was almost normal, and they had a single missense or nonsense mutation in the glucokinase gene glkA. The recombinant strain that was introduced at one of the mutations, glkA Q300K, demonstrated similar but not identical phenotypes to the mutant strain. This result indicates that glkA Q300K is one of the major mutations in 2-DG resistant strains.

Valorization of Banana Peel for Citric Acid Production under Solid State Fermentation with Aspergillus niger

Valorization of banana peel (BP) through solid state fermentation (SSF) was aimed<br /> in this research. The appropriate conditions of citric acid (CA) production by SSF of<br /> Aspergillus niger were investigated. Firstly, the optimum initial pH of the BP and the<br /> aeration rate were studied by conducting SSF in a 250-mL flask and 2-L glass column,<br /> respectively. It was found that the initial pH of the BP and aeration rates affected the CA<br /> production. The results showed that the initial pH of 5.0 and 1.0 vvm aeration were appropriate for the CA production of A. niger using BP as a substrate. The problem of rising temperature during SSF was found when applying the optimum condition to the SSF<br /> in the 20-L packed bed bioreactor (PBB), which caused a decrease in the CA production<br /> compared to that of the glass column. The cooling air jacket constructed to the PBB to<br /> remove the heat during the SSF helped increase the CA production from that in the PBB.<br /> The maximum CA production in the 20-L air-jacketed PBB was 124.0±19.2 mg g–1DS.

Optimum conditions for citric acid production from local Aspergillus niger S11 isolate by submerged fermentation

Optimum conditions for citric acid production from local Aspergillus niger S11 isolate by submerged fermentation

Fermentasi Produksi Asam Sitrat menggunakan Aspergillus Niger ATCC 16404 dengan Substrat Hidrolisat Cair Limbah Padat Industri Brem

Dregs of solid waste brem industry contained 12 percent of sugar and 10,8 percent of starch. Component contained in the dregs are expected to produce citric acid. The aims of this study were to determine the effect of static cultivation on the production of citric acid from liquid hydrolyzate brem waste by using Aspergillus niger. The experimental design used in this study was a simple randomized block design (RAK), which the static cultivations (0, 1, 2, 3 days) as a treatment. The results showed that the static cultivation treatment significantly affected the level of acidity (pH), total soluble solids, biomass, reducing sugar, calcium citrate, citric acid and yield. The static cultivation for 1 day was the best treatment to produce Ca-citrate which the production level was 3,84 ± 0,05 g/L. By the stoichiometry method the citric acid production could be calculated, which equal to 2,12 ± 0,03 g/L.
 Keywords: Aspergillus niger, dregs of brem, static cultivation, Ca-citrate, citric acid 

Influences of carbohydrate, nitrogen, and phosphorus sources on the citric acid production by fungal endophyte Aspergillus fumigatus P3I6

Fungi are ecologically ubiquitous organisms on earth and regarded as one of the prolific sources of natural products. Fungal endophytes may provide essential prerequisite molecules to plant biochemical pathways which allow the efficient synthesis of primary and secondary metabolites. This study characterized the influences of various combinations of process parameters namely, carbohydrate, nitrogen, and phosphorus sources on citric acid (CA) production by the isolated fungal endophyte Aspergillus fumigatus P3I6 from Citrus microcarpa. Aspergillus fumigatus P3I6 had higher CA concentration of 9.2 (± 0.9) g L−1 and 9.0 (± 5.0 × 10−15) g L−1 when supplemented with sucrose and white refined sugar, respectively, than A. niger NRRL 599. Response Surface Methodology (RSM) had shown that A. fumigatus P3I6 produced the highest CA (23.8 g L−1) in Combination 4 (18.0% sucrose, 0.3 g L−1 ammonium sulfate, and 5.0 g L−1 dipotassium phosphate (K2HPO4)). Analysis of variance showed that when K2HPO4 concentrations were increased, CA content in fermentation media was significantly elevated. Hence, K2HPO4 was the most critical variable in the quadratic model (p < 0.05); however, sucrose concentration still has its role in production. Aside from using A. niger in most fermentation processes, this discovered fungal strain can be potentially used in biotechnological applications.

Sirtuin SirD is involved in α-amylase activity and citric acid production in Aspergillus luchuensis mut. kawachii during a solid-state fermentation process

Sirtuins are understood to play a significant role in growth phase-dependent gene expression. In the study presented here, we examined the sirtuins in the white koji fungus, Aspergillus luchuensis mut. kawachii (Aspergillus kawachii), to examine their role in the regulation of amylolytic enzymes and citric acid production during solid-state culture (koji). Characterization of rice koji made using five sirtuin gene disruptants indicated that these genes are involved in the amylolytic activity and acidity of rice koji; the sirD disruptant in particular showed lower levels of acid-stable α-amylase activity and citric acid production per mycelial weight in koji compared to the control strain. The sirD disruptant also showed a change in mycelial pigmentation, and had higher sensitivity to cell wall biogenesis inhibitors such as calcofluor white and Congo red and reduced conidia formation. These results indicate that SirD is required for secondary metabolism, cell wall integrity, and conidial development. Cap analysis gene expression (CAGE) and quantitative RT-PCR analysis indicated that transcriptional changes were related to the characteristic phenotype of the sirD disruptant, including a reduced transcript level of the acid-stable α-amylase gene and a citric acid exporter in rice koji. These results indicate that SirD has a significant role in global transcriptional regulation, including the production of acid-stable α-amylase and citric acid, in A.kawachii during the solid-state fermentation process.

Biotechnological production of natural sweeteners and preservatives on tomato paste

AbstractThere is a growing interest in healthier foods and cleaner labels. In particular, foods containing a lower sugar concentration but with the same organoleptic properties and the same shelf life are becoming a new challenge. To this end, we performed a first set of experimentations on two simple broths (LFM1 and LFM2), which differed in their glucose concentration (250 g/L and 200 g/L, respectively), and a second set of fermentations on two diluted tomato pastes (TP1 and TP2), with the same glucose concentration but different in the presence (TP2) or absence (TP1) of yeast extract. These substrates were fermented by Yarrowia lipolytica ATCC 8661 at 30°C for 192 hr, to understand its ability in simultaneous production of erythritol and citric acid. Although the process should be optimized, in all the cases tested we obtained the erythritol and the citric acid production.Practical applicationThe aim of the present study was the simultaneous production of erythritol and citric acid on a food matrix. This is a preliminary study to obtain, directly by fermentation, a natural sweetener able to give the food product, in particular tomato paste, a sweet taste without adding artificial sweeteners. At the same time, we tried to produce citric acid as a natural preservative to improve shelf life. In this way, we wish to obtain, through several experimentations, semifinished products for the production of vegetal soups and sauces.

Exploring the production of citric acid with Yarrowia lipolytica using corn wet milling products as alternative low-cost fermentation media

The unconventional yeast Yarrowia lipolytica is known for its capability to synthesize different metabolites of industrial interest such as citric acid (CA). The numerous applications of CA trigger continuous research on improved production systems and substrates costs reduction. In this context, the present contribution explored the production of CA using chosen strains of Y. lipolytica in fermentation media formulated with low-cost and non-seasonal nutrient sources derived from the corn wet milling process, such as food grade corn syrups and corn steep liquor (CSL). Besides nutrient sources assay, the effect of carbon source concentration and C/N ratio was evaluated. In media formulated with high fructose syrup and CSL proper manipulation of the mentioned variables allowed attaining CA productions of up to 38 g/L in flasks culture. Moreover, the bioreactor scale-up allowed a 130%-increase in productivity and drastic fermentation time reduction. Overall, the combination of these low-cost nutrient sources of predictable composition derived from the corn processing industry that may be stored at room temperature seems attractive for CA production. The simplicity of the fermentation medium further makes it promising for higher-than-laboratory scale production of CA.

Early-stage sustainability assessment of biotechnological processes: A case study of citric acid production.

Sustainability assessment using a life‐cycle approach is indispensable to contemporary bioprocess development. This assessment is particularly important for early‐stage bioprocess development. As early‐stage investigations of bioprocesses involve the evaluation of their ecological and socioeconomic effects, they can be adjusted more effectively and improved towards sustainability, thereby reducing environmental risk and production costs. Early‐stage sustainability assessment is an important precautionary practice and, despite limited data, a unique opportunity to determine the primary impacts of bioprocess development. To this end, a simple and robust method was applied based on the standardized life‐cycle sustainability assessment methodology and commercially available datasets. In our study, we elaborated on the yeast‐based citric acid production process with Yarrowia lipolytica assessing 11 different substrates in different process modes. The focus of our analysis comprised both cultivation and down‐stream processing. According to our results, the repeated batch raw glycerol based bioprocess alternative showed the best environmental performance. The second‐ and third‐best options were also glycerol‐based. The least sustainable processes were those using molasses, chemically produced ethanol, and soy bean oil. The aggregated results of environmental, economic, and social impacts display waste frying oil as the best‐ranked alternative. The bioprocess with sunflower oil in the batch mode ranked second. The least favorable alternatives were the chemically produced ethanol‐, soy oil‐, refined glycerol‐, and molasses‐based citric acid production processes. The scenario analysis demonstrated that the environmental impact of nutrients and wastewater treatment is negligible, but energy demand of cultivation and down‐stream processing dominated the production process. However, without energy demand the omission of neutralizers almost halves the total impact, and neglecting pasteurization also considerably decreases the environmental impact.

Identification of novel citramalate biosynthesis pathways in Aspergillus niger

BackgroundThe filamentous fungus Aspergillus niger is frequently used for industrial production of fermentative products such as enzymes, proteins and biochemicals. Notable examples of industrially produced A. niger fermentation products are glucoamylase and citric acid. Most notably, the industrial production of citric acid achieves high titers, yield and productivities, a feat that has prompted researchers to propose A. niger to serve as heterologous production host for the industrial production of itaconic acid (IA), a promising sustainable chemical building-block for the fabrication of various synthetic resins, coatings, and polymers. Heterologous production of IA in A. niger has resulted in unexpected levels of metabolic rewiring that has led us to the identification of IA biodegradation pathway in A. niger. In this study we have attempted to identify the final product of the IA biodegradation pathway and analyzed the effect of metabolic rewiring on the bioproduction of 9 industrially relevant organic acids.ResultsIA biodegradation manifests in diminishing titers of IA and the occurrence of an unidentified compound in the HPLC profile. Based on published results on the IA biodegradation pathway, we hypothesized that the final product of IA biodegradation in A. niger may be citramalic acid (CM). Based on detailed HPLC analysis, we concluded that the unidentified compound is indeed CM. Furthermore, by transcriptome analysis we explored the effect of metabolic rewiring on the production of 9 industrially relevant organic acids by transcriptome analysis of IA producing and WT A. niger strains. Interestingly, this analysis led to the identification of a previously unknown biosynthetic cluster that is proposed to be involved in the biosynthesis of CM. Upon overexpression of the putative citramalate synthase and a genomically clustered organic acid transporter, we have observed CM bioproduction by A. niger.ConclusionIn this study, we have shown that the end product of IA biodegradation pathway in A. niger is CM. Knock-out of the IA biodegradation pathway results in the cessation of CM production. Furthermore, in this study we have identified a citramalate biosynthesis pathway, which upon overexpression drives citramalate bioproduction in A. niger.

Techno-economic analysis and environmental impact assessment of citric acid production through different recovery methods

Evaluating the technical feasibility and economic viability of citric acid production at the commercial scale is challenging because it depends on several factors including type of feedstock, process parameters and production routes. In this research, techno-economic and environmental impacts of citric acid production from corn are comparatively evaluated for three scenarios. In the production process Aspergillus niger is used for corn fermentation in a commercial scale of 6400 kg/h citric acid production rate. The scenarios are defined based on application of three recovery methods, including calcium precipitation, solvent extraction, and ion exchange. From three investigated scenarios, the lowest selling price of citric acid is achieved in a scenario using solvent extraction recovery method, followed by the scenario with calcium precipitation recovery method. Sensitivity analysis shows that the minimum selling price of citric acid is highly sensitive to electricity cost, by-product credit, corn supply cost, fermentor cost and wastewater treatment cost. Environmental impacts of citric acid production in three scenarios are assessed using the life cycle assessment approach. Citric acid production with ion exchange recovery method is the most environment-friendly scenario. The results of this research are useful for the development of citric acid production in commercial scale.

EFFECT OF GROUNDNUT CAKE AND SOYA BEANS ON ENHANCED CITRIC ACID PRODUCTION FROM PAWPAW AND ORANGE PEEL BY MUTANTS OF ASPERGILLUS NIGER

This present study was concerned with the biosynthesis of citric acid (CA) with mutant strain of Aspergillus niger using pawpaw and orange peel as substrates by solid state fermentation process. The A. niger strain isolated from spoilt orange was identified, screened for CA production on Czapek-Dox Agar and subjected to mutation by ethidium bromide. The effect of carbon sources, nitrogen sources and substrates were also determined. Among the mutant strains, A. niger PJ-02 A120 was found to be the best mutant that produced citric acid (65.00±0.58f) after 48 hours in Vogel’s medium. The effects of carbon sources (sucrose and glucose) on CA production from each substrate (orange and pawpaw peel) using mutant A. niger PJ-02 was determined and sucrose, the best carbon source was combined with two the nitrogen sources (groundnut cake and soyabeans) to determine the most suitable supplement for CA production. Groundnut cake enhances the production of citric acid while soyabeans was inhibitory. Citric acid was further produced in pawpaw peel and orange peel medium containing sucrose (5 %) groundnut cake (2 %), methanol (1.5 %) and the mutant strain. The orange peel substrates yielded 112.07g/kg of CA while 107.17g/kg was recorded for pawpaw peel when fermented for 5 days at 30°C. The Production of citric acid with mutant Aspergillus niger proved better with orange peel than pawpaw peel when optimized with alcohol.&#x0D; &#x0D; &#x0D;

Disruption of a putative mitochondrial oxaloacetate shuttle protein in Aspergillus carbonarius results in secretion of malic acid at the expense of citric acid production

BackgroundIn filamentous fungi, transport of organic acids across the mitochondrial membrane is facilitated by active transport via shuttle proteins. These transporters may transfer different organic acids across the membrane while taking others the opposite direction. In Aspergillus niger, accumulation of malate in the cytosol can trigger production of citric acid via the exchange of malate and citrate across the mitochondrial membrane. Several mitochondrial organic acid transporters were recently studied in A. niger showing their effects on organic acid production.ResultsIn this work, we studied another citric acid producing fungus, Aspergillus carbonarius, and identified by genome-mining a putative mitochondrial transporter MtpA, which was not previously studied, that might be involved in production of citric acid. This gene named mtpA encoding a putative oxaloacetate transport protein was expressed constitutively in A. carbonarius based on transcription analysis. To study its role in organic acid production, we disrupted the gene and analyzed its effects on production of citric acid and other organic acids, such as malic acid. In total, 6 transformants with gene mtpA disrupted were obtained and they showed secretion of malic acid at the expense of citric acid production.ConclusionA putative oxaloacetate transporter gene which is potentially involved in organic acid production by A. carbonarius was identified and further investigated on its effects on production of citric acid and malic acid. The mtpA knockout strains obtained produced less citric acid and more malic acid than the wild type, in agreement with our original hypothesis. More extensive studies should be conducted in order to further reveal the mechanism of organic acid transport as mediated by the MtpA transporter.

Utilization of banana peel waste for citric acid production by Aspergillus niger

The potential of Banana peel waste of Pisang Ayam (Musa acuminata), Pisang Raja (Musa Paradisiaca cv. Raja genom AAB), and Pisang Nipah (Musa balbisiana) as substrat for citric acid production by Aspergilus niger have been investigated. The main purpose of this research was to determine the percentages of citric acid production, pH, and total biomass at differences of media of banana peel waste. The results showed that the percentages of citric acid production using media of Musa acuminata, Musa Paradisiaca cv. Raja genom AAB and Musa balbisiana were 58.80, 69.84, and 46.80% respectively. The pH values of each media were 2.50, 1.50, and 2.0 respectively. The results also founded that the total biomass of each media were 2.442, 2.649, and 2.407 respectively. Overall, the results showed that banana peel waste of Musa Paradisiaca produce the highest amount of citric acid after 240 h fermentation.

The Phase Morphology of Citrogypsum Waste Controlled by a Hydrothermal Process in Ethylene Glycol/Water Solutions

The acid purification of calcium citrate from citric acid production using sulfuric acid as a reagent resulted in citrogypsum waste. The identification of citrogypsum by XRD technique indicates that the main component consists of CaSO4∙2H2O (DH). Furthermore, the comparison of the colours between citrogypsum and natural gypsum are also different. Hence, this research mainly focused on the phase transformation of DH to α-CaSO4 ∙0.5H2O (α-HH) due to high strength and heat resistant. The preparation of α-HH carry out in different volume ratios of ethylene glycol (EG): water solutions at 95oC for 7 hrs under atmospheric pressure. The FT-IR spectra of DH and α-HH results reveal that the absorption frequencies at 1700 and 1800 cm-1 of –OH group are 0.5 and 1.5 water molecule in CaSO4 respectively. TGA thermograms show the theoretical crystal water content of DH approximately 20.1 wt% and the converted α-HH about 4-5 wt%. DSC thermograms of the citrogypsums show two endothermic peaks regarding to two steps of water molecule loss at 151.2oC and 168.5oC respectively. In addition, the α-HH shows exothermic peak at 238.7oC. The morphology of citrogypsum and α-HH are observed by SEM, showing the plate-like shape of citrogypsum and hexagonal shape of α-HH. Moreover, the products could be applied to several other industries for increasing the value and reducing the environmental concerns.