Dry Mycelium Research Articles

English

The influence of the four species of green sponges (Ephydatia muelleri, Heteromeyenia stepanowii, Spongilla fluviatilis, and Spongilla lacustris) on the occurrence of aquatic mycotal species in the water of three four water bodies of different trophy was investigated in this study. Seeds and snake exuviae were used as baits. For the measurement of the primary and extracellular production by symbiotic algae of green sponges and assimilation of those products by mycota, radioactive carbon (14C) was used. A total of 75 mycotal species were found to be growing on the baits. The fewest mycota were noted in the containers in water from oligotrophic Lake HaA„cza; the most in the containers with eutrophic water from River SupraA›l. More mycota were found to grow in the containers with green sponges (Sp) than in the controls (Co) in water from all water bodies. The mean ratio of Sp/Co in green sponges ranged from 2.30 (E. muelleri) to 4.80 (H. stepanowii); in brown colonies (without symbiotic algae) it was 0.90. Mean value of 14C fixation (primary production) in symbiotic algae of Spogilla fluviatilis was 5.67 mg C g-1 dry weight sponge per hour. The effect of green sponges on the abundance of aquatic mycotal species is caused by dissolved organic matter produced during photosynthesis by symbiotic zoochlorellae, a symbionts of green sponges and excreted into the water environment (S. fluviatilis excreted mean 12.8% of carbon fixation). Those excreted organic substances serve as nutrients for aquatic mycota. The mean value of extracellular products assimilated by mycota was 4.96 mg C g-1 dry weight mycelium per hour. Key words: Sponges, symbiotic zoochlorellae, aquatic mycota, interactions, hydrochemistry.

Biodegradation kinetics of thin-stillage treatment by Aspergillus awamori and characterization of recovered chitosan.

An attempt has been made to provide solution for distillery wastewater using fungal pretreatment followed by an anaerobic process to achieve higher organic matter removal, which is a challenge at present with currently adopted technologies. Submerged growth kinetics of distillery wastewater supernatant by Aspergillus awamori was also evaluated. The proposed kinetic models using a logistic equation for fungal growth and the Leudeking-Piret equation for product formation were validated experimentally, and substrate consumption equation was derived using estimated kinetic coefficients. Up to 59.6 % chemical oxygen demand (COD) and 70 % total organic carbon (TOC) removals were observed in 96 h of fungal incubation. Maximum specific growth rate of fungi, coefficient of biomass yield on substrate and growth-associated product formation coefficient were estimated to be 0.07 ± 0.01 h(-1), 0.614 kg biomass/kg utilized COD and 0.215 kg CO2/kg utilized TOC, respectively. The chitosan recovery of 0.072-0.078 kg/kg of dry mycelium was obtained using dilute sulphuric acid extraction, showing high purity and characteristic chitosan properties according to FTIR and XRD analyses. After anaerobic treatment of the fungal pretreated effluent with COD concentration of 7.920 ± 0.120 kg COD/m(3) (organic loading rate of 3.28 kg COD/m(3) day), overall COD reduction of 91.07 % was achieved from distillery wastewater.

Dry mycelium of Penicillium chrysogenum activates defense responses and restricts the spread of Tobacco Mosaic Virus in tobacco

Microbes and microbial metabolites/molecules-induced resistance is known to protect plants from several invaders, including viruses. We studied a water extract of dry mycelium of Penicillium chrysogenum (DMP)-induced defense responses and determined whether this extract protects tobacco from Tobacco Mosaic Virus (TMV). Transcripts of four genes – PAL, 4CL, C4H and LPO that are involved in the synthesis of secondary metabolites and the contents of phenolic compounds, scopoletin and lignin, were rapidly induced in DMP-treated BY-2 cell suspensions that were derived from Nicotiana tabacum L. cv. Bright Yellow-2, indicating a DMP-induced resistance in BY-2 cells. Transcripts of the salicylic acid (SA)-dependent gene PR-1a were rapidly induced after DMP treatment, indicating the activation of SA-dependent signaling pathway. The expression of the jasmonic acid (JA)-responsive gene PDF1.2 suggests that DMP might induce distinct signaling pathways simultaneously. A 30B vector carrying the green fluorescent protein gene (30B:GFP) was used to monitor the replication of the virus vector in BY-2 cells and tobacco plants. The spread of the virus vector was impaired both in DMP-pretreated BY-2 cells and tobacco plants, indicating that DMP helped protect tobacco against TMV. Our data suggest that the DMP activates defense responses in tobacco BY-2 cell suspensions, including the accumulation of secondary metabolites and the expression of defense responses genes, and protects tobacco from TMV.

MYCOLYTIC ACTIVITY OF PHOSPHATE MOBILIZING SOILBA CTERIA OF GENUS BACILLUS COHN

The aim of this research was study of the chitinolytic activity of phosphateobilizing soil bacteria of genus Bacillus and their antagonistic properties towards microscopic fungi. Methods. In this research 16 strains of phosphate-mobilizing soil bacteria of genus Bacillus and saprophytic and plant pathogenic strains of micrtomycetes were investigated. The antagonistic activity of bacilli against micromycetes was determined by the method of blocks and holes. Bacilli on agar medium and also their supernatants were used. Inhibition of fungal growth under co-cultivation with bacilli under static conditions in the liquid culture medium was determined gravimetrically by the difference of dry weight mycelium in control and in experiment. Bacilli chitinolytic activity was determined photocolorimetrically by the formation of reducing sugars by hydrolysis of colloidal chitin using 3,5-dinitrosalicylic acid. Student test for 5% significance level was used for statistical processing of the obtained data. Results. The presence of chitinolytic activity in all tested bacilli in colloidal chitin medium was established. B. megaterium 16, B. pumilus 7, B. cereus v mycoides 10 strains showed high chitinolytic activity, they were also characterized by high antagonistic activity against plant pathogenic fungi (Fusarium oxysporum 54 and Trichothecium roseum 658). Bacilli were capable to using autoclaved mycelium as the sole of carbon and nitrogen source. Cultivation of bacteria and microscopic fungi under static conditions showed growth inhibition and changes in morphological features – blistering and areas of lysis of mycelium. Conclusions. It was established that phosphate-mobilizing strains of soil bacteria of the genus Bacillus showed chitinolytic activity and growth inhibition of plant pathogens and caused their morphological changes in co-culture. The direct relationship between the antagonistic and chitinolytic activity of bacilli was demonstrated. The bacilli ability to use autoclaved fungal mycelium as a sole source of carbon and nitrogen was showed on the example of B. cereus v. mycoides 10.

Effect of Carum copticum essential oil on growth and aflatoxin formation by Aspergillus strains

The objectives of this study were to determine the antiaflatoxin B1 activity in vitro of the essential oil (EO) extracted from the seeds of Carum copticum and to evaluate its antifungal activity in vivo as a potential food preservative. The C. copticum EO exhibited noticeable inhibition on dry mycelium and synthesis of aflatoxin B1 (AFB1) by Aspergillus flavus, completely inhibiting AFB1 production at 4 μL/mL. C. copticum EOs showed the lowest percentages of decayed cherry tomatoes for all fungi compared with the control at 100 μL/mL with values of 5.01 ± 67% for A. flavus and 5.98 ± 54% for Aspergillus niger. The results indicated that the percentage of infected fruits is significantly (p < 0.01) reduced by the EO at 16°C for 30 days. In this case, the oil at 100 μL/mL concentration showed the highest inhibition of fungal infection with a value of 80.45% compared with the control. Thus, the EO of dill could be used to control food spoilage and as a potential source of food preservative.

Study of different temperature levels on radial growth and dry mycelial weight of Trichoderma spp. isolated from red gram based conservation agriculture ecosystem

Different temperatures and pH were taken to observe the radial growth and dry mycelial weight of Trichoderma spp. The radial growth of Trichoderma was maximum for all the four species i.e., T. harzianum, T. viride, T. hamatum and T. virens (90, 82, 91.3 and 85mm) at 30oC, where it was minimum in four species at 40oC (30.70, 35, 22.53 and 20 mm), respectively and dry mycelium of T. harzianum (1.05 mg), T. viride (1.83 mg), T. hamatum (2.42 mg) and T. virens (0.82 mg) were maximum at 25oC whereas, the radial growth of four isolates were maximum at pH 6 (90, 88, 92 and 91mm) in T. harzianum, T. viride, T. hamatum and T. virens, respectively. At neutral pH, radial growth of T. harzianum (89 mm), T. viride (91 mm), T. hamatum (89 mm) and T. virens (87 mm) was minimum and dry mycelium weight of T. harzianum (729 mg), T. viride (1639.67 mg), T. hamatum (798 mg) and T. virens (583.67 mg) were maximum at pH 8. It was minimum at pH 4 for T. harzianum (120 mg), T. viride (257 mg), T. hamatum (154 mg) and T. virens (262.67 mg).

Zanthoxylum molle Rehd. essential oil as a potential natural preservative in management of Aspergillus flavus

Essential oils are attracting attention owing to their potential as natural antimicrobial agents, and therefore, they find many applications in the food and pharmaceutical industries. This investigation aimed to evaluate the antifungal activity of Zanthoxylum molle essential oil (ZMEO) against Aspergillus flavus, a food contaminant. Gas chromatography–mass spectrometry detected 51 compounds representing 95.72% of the ZMEO. 2-Undecanone (26.81%), limonene (20.12%), and terpinen-4-ol (13.09%) were the main components. The mycelial growth of A. flavus was totally inhibited at concentrations of 8μL/mL and 1μL/mL ZMEO in the air at contact and vapor conditions, respectively. The ZMEO also had an inhibitory effect on spore germination in A. flavus proportional to its concentration. Moreover, the ZMEO presented evident inhibition on dry mycelium weight and synthesis of aflatoxin B1 (AFB1) by A. flavus, completely restraining AFB1 production at 6μL/mL. This study explores the possible mechanism of the ZMEO against A. flavus by transmission electron microscopy based on changes in the cell ultrastructure. Based on the promising antifungal activity of ZMEO, the effect of the oil on resistance to decay development in cherry tomatoes (Lycopersicon esculentum) was studied in vivo by exposing inoculated and control fruit groups to essential oil vapor at 0.4μL/mL air concentration. The results showed that ZMEO can potentially be used as an antifungal agent for preservation purposes in the food and pharmaceutical industries.

Industrial Fermentation Waste &lt;i&gt;Aspergillus niger&lt;/i&gt; as Adsorbent for Sequestering Cr&lt;sup&gt;6 +&lt;/sup&gt; from Aqueous Solution

Biosorption of Cr6 + ions by industrial fermentation waste Aspergillus niger free dry mycelium was investigated in a batch system..The influences of Cr6 +concentration, biosorbent dose, solution pH and contact time on Cr6 +were investigated.Optimum biosorption was observed to be 73.5% at pH 5,biosorbent dose 20g/L, initial Cr6 + concentration 100 mg/L. Adsorption equilibrium was established in 800 min at 30°C. The Langmuir model compared to the Biosorption equilibrium data were best described by Langmuir isotherm model, R2=0.9999.

Effect of Different Cultural Condition on the Growth of Fusarium moniliforme Causing Bakanae Disease

In this study, Fusarium moniliforme causal organism of Bakanae disease has been isolated from infected rice seeds variety Pusa Basmati-1121 by using blotter technique. The effects of temperature, pH and carbon source on radial growth rate were assessed on potato dextrose broth medium. Precise characterisation of the growth conditions for such a fungal pathogen has an evident interest to understand and to prevent spoilage of rice crops. Study was carried out to check the effect of temperature (15-50 °C), pH (2-10), and different carbon sources (glucose, dextrose, sucrose, rice husk and sugarcane bagasse) on the growth Fusarium moliniforme. Optimum temperature and pH for growth was 20 °C and 5.0 with maximum dry mycelium weight and sporulation i.e. 2.168 gm 1.806 million spores / 100ml respectively. Maximum growth was observed when rice husk was used as sole carbon source (2.432 gm and 1.68 million spore/ 100 ml) however maximum sporulation (0.984 million spore/ 100 ml) was achieved when sugarcane bagasse was used as sole carbon source.

Biological Control of the Weed Hemp Sesbania (Sesbania exaltata) in Rice (Oryza sativa) by the Fungus Myrothecium verrucaria

In greenhouse and field experiments, a mycelial formulation of the fungus Myrothecium verrucaria (IMI 361690) containing 0.20% Silwet L-77 surfactant exhibited high bioherbicidal efficacy against the problematic weed hemp sesbania. Infection and mortality levels of 100% of hemp sesbania seedlings occurred within 48 h after fungal application in the greenhouse. In rice field tests conducted over a three year period, M. verrucaria at an inoculum concentration of 50 g L−1 (dry mycelium equivalent) controlled 95% of ≤20 cm tall hemp sesbania plants. M. verrucaria also controlled larger plants (≥60 cm tall) using this high inoculum concentration. This level of weed control, as well as rice yields from plots where weeds were effectively controlled, were similar to those which occurred with the herbicide acifluorfen. These results suggest that a mycelial formulation of M. verrucaria has potential as a bioherbicide for controlling hemp sesbania in rice.

Enzymes and qualitative phytochemical screening of endophytic fungi isolated from Lantana camara Linn. Leaves

Plants harbor endophytes, capable of producing metabolites and enzymes with functions similar to host plant extracts. An inventory of Lantana camara’s endophytes could better explain the role played by extracts of this plant in its defense functions against pathogens. This study aimed at isolating and screening endophytic fungi from L. camara leaves for amylases, lipases and laccases production and for the production of some secondary metabolites using standard procedures. In-vitro culture techniques with Potato Dextrose Agar (PDA) as culture medium were used to isolate endophytes from L. camara leaf tissues. Isolates identification were done using macroscopic and microscopic characteristics. Three endopyhtic fungi were isolated and labeled LI, LII, and LIII; LI and LII had a slimy texture and produced no reproductive structures (spores, conidia, septate hyphae etc) hence identified as mycelia sterilia. LIII was white, with an uneven surface growth, cottony dry aerial mycelium, visible hyphae with little branching and individual hyphae were septate, hence a Geotrichium sp. All isolates produced amylases and lipases while LIII solely produced laccase. The extract of LIII showed the presence of tannins and cardiac glycosides and absence of phenols and saponnins. The anti pathogenic roles of L. camara extract are thanks to the presence of endophytes in its tissues which produce enzymes that mediate plant defense functions as well as secondary metabolites with anti- pathogenic properties.

Arsenite Resistance, Accumulation, and Volatilization Properties of Trichoderma asperellumSM‐12F1, Penicillium janthinellumSM‐12F4, and Fusarium oxysporum CZ‐8F1

It is expected that microorganisms capable of arsenic (As) accumulation and volatilization can be used to remediate As‐contaminated environments. In this paper, the arsenite [As(III)] resistance, accumulation, and volatilization properties of Trichoderma asperellum SM‐12F1, Penicillium janthinellum SM‐12F4, and Fusarium oxysporum CZ‐8F1 were investigated. The results indicated that all three fungal strains exhibited significant As(III)‐resistance. After being exposed to 40 and 80 mg/L As(III) for five days, the dry mycelium weights of P. janthinellum SM‐12F4 and F. oxysporum CZ‐8F1 were significantly increased compared to the controls. The spiked As(III) initially inhibited and subsequently promoted fungal growth (mainly in the logarithmic growth phase). The maximal biomasses of 0.25, 0.29, and 0.29 g for T. asperellum SM‐12F1, P. janthinellum SM‐12F4, and F. oxysporum CZ‐8F1 after exposure to As(III), respectively, were all higher than their corresponding controls without As(III). When exposed to 40 mg/L As(III) for five days, the efficiencies of As(III) accumulation for T. asperellum SM‐12F1, P. janthinellum SM‐12F4, and F. oxysporum CZ‐8F1 were 53.02, 13.67, and 13.65 µg/g/day, respectively, and the efficiencies of As(III) volatilization were 51.87, 54.34, and 46.35 µg/g/day, respectively. It seems that these fungal strains can be used in the future to tackle As‐contaminated environments.

Guava Psidium guajava seed flour and dry Aspergillus niger mycelium as nitrogen sources for the production of biomass and antimicrobial compounds produced by Weissella confusa

Background: The fermentation substrate efficiency of glucose supplemented with guava seed flour (GGSF) or glucose supplemented with dry Aspergillus niger mycelium (GANM) was evaluated during the production of biomass and antimicrobial compounds by the lactic acid bacteria Weissella confusa . Results: The fermentation substrate efficiency was measured by comparing the biomass formation, substrate consumption, substrate conversion, antimicrobial activity and product yield. The antimicrobial activity was measured against a commercial Staphylococcus aureus strain. The results were compared against fermentations performed in a commercial substrate (CS), the MRS (Man-Rogosa-Sharpe) substrate. The fermentations were performed discontinuously for 4 hrs at 100 rpm and 32ºC. The biomass production exhibited a statistically significant difference (P ≤ 0.05) between treatments. The biomass production was 13.98% higher in the CS than in the GGSF and GANM substrates; however, there were no statistically significant differences for the specific growth rate. Conclusions: The GGSF and GANM substrates favored an antimicrobial activity against Staphylococcus aureus during the second and third hours of fermentation (inhibition diameter was 6.11% and 4.72%, respectively). The GGSF, GANM and CS substrates did not present statistically significant differences for the production of antimicrobial substances against Staphylococcus aureus . Therefore, GGSF and GANM can be considered as viable and economical alternative nitrogen sources for the production of the antimicrobial compounds formed by Weissella confusa in submerged fermentations .

Biosorption of Arsenic (III) from Aqueous Solutions by Industrial Fermentation Waste &lt;i&gt;Aspergillus niger&lt;/i&gt;

Biosorption of As3+ ions by industrial fermentation waste Aspergillus niger free dry mycelium was investigated in a batch system..The influences of solution pH, biosorbent dose, As3+concentration, and contact time on As3+ were studied.The results indicatd that absorption capacity was strongly affected by the solution pH, the biosobent dose and initial As3+concentration.Optimum biosorption was observed to be 75% at pH 5.0,biosorbent dose 20g/L, initial As3+concentration 800ug/L. Adsorption equilibrium was established in 100 min. Biosorption equilibrium data were best described by Langmuir isotherm model.

Biotransformation with whole microbial systems in a continuous flow reactor: resolution of (RS)-flurbiprofen using Aspergillus oryzae by direct esterification with ethanol in organic solvent

Cell-bound lipases of dry mycelium of Aspergillus oryzae were used in organic solvent for the resolution of racemic flurbiprofen by direct esterification with ethanol in a flow-chemistry reactor. Under flow conditions a significant reduction of the reaction time and an increase of the enantioselectivity were achieved compared to the batch mode. Moreover, the process was implemented by adding an in-line purification step integrated with the racemization of the unreacted flurbiprofen directly into a polymer-supported resin.

Kinetic models and process parameters for ultrasound-assisted extraction of water-soluble components and polysaccharides from a medicinal fungus

This study was on the kinetics and process parameters for ultrasound-assisted extraction (UAE) of water-soluble components and polysaccharides (PS) from the dry mycelium of a medicinal fungus, Cordyceps sinensis Cs-HK1. Four process variables (factors) were evaluated at different levels, ultrasound intensity (2.44–44.1W/cm2), temperature (40–70°C), solid particle size (156.5–750μm), and solid-to-liquid ratio (1/30–1/70g/mL). The experimental data of yields versus time in most cases were fitted closely to two empirical kinetic models for solid–liquid extraction, parabolic diffusion equation (y=yo+y1t1/2) and power law (y=βtn) with high correlation coefficients (R2) of 0.95–0.99 for total extract yield, and 0.90–0.96 for PS yield. The PS yield was increased more significantly than the total extract yield with the ultrasound intensity. Reducing the particle size and increasing the extraction temperature led to a higher yield and extraction rate; increasing the solid-to-liquid ratio (or decreasing the liquid volume) increased the PS yield and extraction rate but had little influence on the total extract. Significant correlations were found between extraction rate (dy/dt) and ultrasound power density (P/V), and between extract yield (y) and energy density (Pt/V). The kinetic and process parameters are useful for rational design and efficient operation of UAE processes.

De Novo Sequencing and Transcriptome Analysis of Wolfiporia cocos to Reveal Genes Related to Biosynthesis of Triterpenoids

Wolfiporia cocos Ryvarden et Gilbertson is a saprophytic fungus in the Basidiomycetes. Its dried sclerotium is widely used as a traditional crude drug in East Asia. Especially in China, the dried sclerotium is regarded as the silver of the Chinese traditional drugs, not only for its white color, but also its medicinal value. Furthermore, triterpenoids from W. cocos are the main active compounds with antitumor and anti-inflammatory activity. Biosynthesis of the triterpenoids has rarely been researched. In this study, the de novo sequencing of the mycelia and sclerotia of W. cocos were carried out by Illumina HiSeq 2000. A total of 3,484,996,740 bp from 38,722,186 sequence reads of mycelia, and 3,573,921,960 bp from 39,710,244 high quality sequence reads of sclerotium were obtained. These raw data were assembled into 60,354 contigs and 40,939 singletons, and 56,938 contigs and 37,220 singletons for mycelia and sclerotia, respectively. The transcriptomic data clearly showed that terpenoid biosynthesis was only via the MVA pathwayin W. cocos. The production of total triterpenoids and pachymic acid was examined in the dry mycelia and sclerotia. The content of total triterpenoids was 5.36% and 1.43% in mycelia and sclerotia, respectively, and the content of pachymic acid was 0.458% and 0.174%. Some genes involved in the triterpenoid biosynthetic pathway were chosen to be verified by qRT-PCR. The unigenes encoding diphosphomevalonate decarboxylase (Unigene 20430), farnesyl diphosphate synthase (Unigene 14106 and 21656), hydroxymethylglutaryl-CoA reductase (NADPH) (Unigene 6395_All) and lanosterol synthase (Unigene28001_All) were upregulated in the mycelia stage. It is likely that expression of these genes influences the biosynthesis of triterpenoids in the mycelia stage.

Resolution of (R, S)-ethyl-2-(4-hydroxyphenoxy) propanoate using lyophilized mycelium of Aspergillus oryzae WZ007

• The kinetic resolution of ( R , S )-EHPP by Aspergillus oryzae WZ007 lipase is proposed. • The key biocatalytic process parameters were optimized. • The optical purity of ( R )-EHPP was up to >99% and the conversion was above 49%. The mycelium of Aspergillus oryzae WZ007 was successfully developed to kinetic resolution of ( R , S )-ethyl-2-(4-hydroxyphenoxy) propanoate (( R , S )-EHPP) for production of ( R )-ethyl-2-(4-hydroxyphenoxy) propanoate (( R )-EHPP). The key biocatalytic process parameters (pH, temperature, rotation speed and substrate concentration) were optimized. Under the optimum conditions, the optical purity of ( R )-EHPP was improved up to >99% when the conversion was above 49%. A. oryzae WZ007 whole-cell lipase exhibited high reaction capacity, enantioselectivity and good reusability. The tolerable substrate concentration was 0.5 mol/L, and dry mycelium of A. oryzae WZ007 maintains over 80% of its initial activity after eight repeating cycles. Therefore the enzymatic preparation of ( R )-EHPP route was suitable for industrial application.

Ganoderma lucidum: A Potential for Biotechnological Production of Anti-Cancer and Immunomodulatory Drugs

Based on the analysis of more than 270 patents and scientific articles, this state-of-the-art review presents Ganoderma lucidum, a medicinal basidiomycete mushroom with immunomodulatory and anti-cancer effects. Cultivation methods for the commercial production of G. lucidum fruit bodies and mycelia are summarized, with main active compounds of triterpenoids, polysaccharides, and proteins, often found in forms of proteoglycans or glycopeptides. Pharmacological effects with emphasis on anti-cancer and immunomodulatory functions are presented, separately for spores and dry mycelia, and for the groups of triterpenoids, polysaccharides, proteins and glycoproteins. Patents disclosing preparation methods of extracts and purified pharmaceutical isolates are reviewed, and examples of anti-cancer formulations, used as pharmaceuticals or nutraceuticals, are given. The review suggests that according to the present understanding, the anti-cancer activity of G. lucidum may be attributed to at least five groups of mechanisms: (1) activation/modulation of the immune response of the host, (2) direct cytotoxicity to cancer cells, (3) inhibition of tumor-induced angiogenesis, (4) inhibition of cancer cells proliferation and invasive metastasis behaviour, and (5) carcinogens deactivation with protection of cells. Although, the data from recent in vitro and in vivo studies demonstrate promising anti-cancer effects, a need is identified for further (1) isolation and purification of compounds, with deeper understanding of their individual and synergistic pharmacological effects, (2) molecular level studies of the antitumor and immuno-supportive mechanisms, (3) well designed in vivo tests and controlled clinical studies, and (4) standardisation and quality control for G. lucidum strains, cultivation processes, extracts and commercial formulations.

Deletion of pigR gene in Monascus ruber leads to loss of pigment production

Pigments produced by Monascus are traditional food colorants and are widely used as dietary supplements. Since genes involving in pigment biosynthesis have not been reported, we describe the identification of a putative pigment-regulatory gene (pigR) obtained by molecular analysis of an albino strain of Monascus ruber M7. In the pigR-deleted strain (ΔpigR), neither the pigments nor pigR expression were detected by HPLC or reverse-transcription PCR, respectively, whereas the introduction of the pigR, together with a constitutive trpC promoter into ΔpigR, caused it to produce 5.4U of red pigments/g dry mycelia, about 12-fold higher than Monascus ruber M7 (0.46U/g dry mycelia). Thus pigR up-regulates pigment production in Monascus ruber M7.