Enhanced Pigment Production Research Articles

Improving the medium composition for the production of the natural blue-violet pigment violacein by a new Janthinobacterium sp. isolate.

The interest in natural compounds has increased primarily due to their beneficial health and environmental aspects. However, natural sources of some compounds, such as bluish pigments, are limited, requiring the development of efficient processes to meet commercial demands. This study isolated a blue-violet bacterium from spoiled cooked rice and identified it as a potential new species of Janthinobacterium through 16S rDNA analysis. Ultra-high performance liquid chromatography-tandem mass spectrometry analyses confirmed that the blue-violet pigment violacein was responsible for the bluish color. In laboratory conditions, different carbon and nitrogen sources were evaluated in submerged culture media to enhance pigment production. Glycerol did not result in significant pigment production by this strain, as expected from previous reports. Instead, a culture medium composed of yeast extract and fructose yielded higher pigment production, reaching about 113.68±16.68 mg l-1 after 120 h. This result provides crucial insights for future studies aiming for sustainable and commercially viable violacein production. Based on a bioeconomy concept, this approach has the potential to supply natural and economic bluish pigments for various industrial sectors, including pharmaceutical, cosmetic, and food.

Optimized carotenoid production and antioxidant capacity of Gordonia hongkongensis.

The current emphasis within the cosmetic market on sustainable ingredients has heightened the exploration of new sources for natural, active components. Actinomycetota, recognized for producing pigments with bioactive potential, offer promising functional cosmetic ingredients. This study aimed to optimize pigment and antioxidant metabolite production from the Gordonia hongkongensis strain EUFUS-Z928 by implementing the Plackett-Burman experimental design and response surface methodology. Extracts derived from this strain exhibited no cytotoxic activity against human primary dermal fibroblast (HDFa, ATCC® PCS-201-012™, Primary Dermal Fibroblast; Normal, Human, Adult). Eight variables, including inoculum concentration, carbon and nitrogen source concentration, NaCl concentration, pH, incubation time, temperature, and stirring speed, were analyzed using the Plackett-Burman experimental design. Subsequently, factors significantly influencing pigment and antioxidant metabolite production, such as temperature, inoculum concentration, and agitation speed, were further optimized using response surface methodology and Box-Behnken design. The results demonstrated a substantial increase in absorbance (from 0.091 to 0.32), DPPH radical scavenging capacity (from 27.60% to 84.61%), and ABTS radical scavenging capacity (from 17.39% to 79.77%) compared to responses obtained in the isolation medium. The validation of the mathematical model accuracy exceeded 90% for all cases. Furthermore, liquid chromatography coupled with mass spectrometry (LC-MS) facilitated the identification of compounds potentially responsible for enhanced pigment production and antioxidant capacity in extracts derived from G. hongkongensis. Specifically, six carotenoids, red-orange pigments with inherent antioxidant capacity, were identified as the main enhanced compounds. This comprehensive approach effectively optimized the culture conditions and medium of a G. hongkongensis strain, resulting in enhanced carotenoid production and antioxidant capacity. Beyond identifying bioactive compounds and their potential cosmetic applications, this study offers insights into the broader industrial applicability of these extracts. It underscores the potential of G. hongkongensis and hints at the future utilization of other untapped sources of rare actinomycetes within the industry.

A Wild Pseudomonas has appeared: An Exercise in Bacterial Isolation and Identification

<span id="docs-internal-guid-8e962b78-7fff-c5ee-bc79-1ba2a6c149e3"><span>The aim of our research was to isolate and identify wild type </span><span>Pseudomonas putida </span><span>from soil in various cities of San Gabriel Valley. </span><span>P. putida </span><span>is</span><span>capable of biomineralization. Biomineralization can potentially be used as a method of phosphorus recovery by using bacteria to produce phosphate rich struvite. In isolating bacteria for further observation, fluorescence was used as a primary determinant in identifying possible </span><span>Pseudomonas </span><span>strains as fluorescence is a common trait shared among varying </span><span>Pseudomonas </span><span>species; </span><span>P. putida, P. aeruginosa</span><span>,</span><span> P. fluorescens</span><span>,</span><span> P. cichorii</span><span>,</span><span> P. chlororaphis</span><span>,</span><span> P. syringae</span><span>,</span><span>and </span><span>P. aureofaciens</span><span>. King’s B agar was used to promote the production of pyoverdine in these strains (allowing for direct identification based on a green fluorescence under UV light) as this medium has specific ingredients that enhance pigment production.</span><span>These fluorescent bacteria were then further isolated from each other and identified using biochemical methods including catalase, oxidase, nitrate reduction, and gelatin hydrolysis tests to differentiate </span><span>P. putida </span><span>from the six other fluorescent </span><span>Pseudomonas </span><span>species. Of the 21 total samples isolated based on fluorescence, 5 of the samples were determined to be potential </span><span>P. putida. </span><span>While the biochemical assays were conducted, the isolated samples were placed in refrigeration for 3 weeks. After the biochemical tests were completed and 3 weeks had passed, visible crystals had formed in the potential </span><span>P. putida</span><span>. Albert’s metachromatic staining was performed to determine the presence of polyphosphate granules. Ultimately, each potential </span><span>P. putida</span><span> that produced crystals also showed polyphosphate granules when Albert’s stained, which further connects crystal formation with prior polyphosphate formation.</span></span>

Valorization of pineapple peel waste for fungal pigment production using Talaromyces albobiverticillius: Insights into antibacterial, antioxidant and textile dyeing properties

The present study explores natural pigments as sustainable alternatives to synthetic textile dyes. Due to their therapeutic applications and easy production, fungal pigments have gained attention. However, data on pigment production using solid-state fermentation and optimization is limited. Milk whey was used to grow Talaromyces sp., followed by an evaluation of pigment production in solid and liquid media. Pineapple peels were used as a cost-effective substrate for pigment production, and a one-factor-at-a-time approach was used to enhance pigment production. Pineapple peel-based media produced 0.523 ± 0.231 mg/g of pigment after eight days of incubation. The crude pigment had promising antibacterial and significant antioxidant properties. The extraction fungal pigment's possible use as an eco-friendly textile dye was assessed through fabric dyeing experiments with different mordants. This work contributes to the valorization of agricultural waste and provides insight into using fungal pigments as sustainable alternatives to synthetic textile dyes.

Colorful Treasure From Agro-Industrial Wastes: A Sustainable Chassis for Microbial Pigment Production.

Colors with their attractive appeal have been an integral part of human lives and the easy cascade of chemical catalysis enables fast, bulk production of these synthetic colorants with low costs. However, the resulting hazardous impacts on the environment and human health has stimulated an interest in natural pigments as a safe and ecologically clean alternative. Amidst sources of natural producers, the microbes with their diversity, ease of all-season production and peculiar bioactivities are attractive entities for industrial production of these marketable natural colorants. Further, in line with circular bioeconomy and environmentally clean technologies, the use of agro-industrial wastes as feedstocks for carrying out the microbial transformations paves way for sustainable and cost-effective production of these valuable secondary metabolites with simultaneous waste management. The present review aims to comprehensively cover the current green workflow of microbial colorant production by encompassing the potency of waste feedstocks and fermentation technologies. The commercially important pigments viz. astaxanthin, prodigiosin, canthaxanthin, lycopene, and β-carotene produced by native and engineered bacterial, fungal, or yeast strains have been elaborately discussed with their versatile applications in food, pharmaceuticals, textiles, cosmetics, etc. The limitations and their economic viability to meet the future market demands have been envisaged. The most recent advances in various molecular approaches to develop engineered microbiological systems for enhanced pigment production have been included to provide new perspectives to this burgeoning field of research.

Effect of Molasses Concentration on the Pigment Production of Monascus purpureus M9 on Monascus Fermented Durian Seed

Efforts have been made to cultivate Monascus purpureus on durian seed to produce Monascus Fermented Durian Seed (MFDS). MFDS pigment production could be enhanched by substrate addition by adding carbon source such as molasses. The purpose of this study was to determine the effect of molasses concentration on the production of M.purpureus M9 pigment in MFDS. The research used randomized block design with one factor, namely the concentration of molasses (M) with six treatment levels, M0 = 0%; M1 = 2%; M2 = 4%; M3= 6%; M4 = 8% and M5 = 10% with four repetitions. Findings showed that molasses addition had a significant effect on the color of MFDS powder, water soluble pigment level, 99.9% ethanol soluble pigment level and the pigment profile for both solvents. The best treatment based on pigment content was the M4 treatment with an ‘L value’ of 43.83, a* value of 14.92, b* value of 7.08, C value of 16.54, oH value of 24.45 and aquades soluble pigment content of 16.86AU/g (yellow); 9.23AU/g (orange); and 8.19AU/g (red) and ethanol soluble pigment content of 9.8AU/g (yellow); 2.5AU/g (orange); and 3.0 AU/g (red). Molasses is able to enhance pigment production of Monascus purpureus M9 of MFDS.

Isolation and Optimization of Monascus ruber OMNRC45 for Red Pigment Production and Evaluation of the Pigment as a Food Colorant

The color of food is a critical factor influencing its general acceptance. Owing to the effects of chemical colorants on health, current research is directly aimed at producing natural and healthy food colorants from microbial sources. A pigment-producing fungal isolate, obtained from soil samples and selected based on its rapidity and efficiency in producing red pigments, was identified as Monascus ruber OMNRC45. The culture conditions were optimized to enhance pigment production under submerged fermentation. The optimal temperature and pH for the highest red pigment yield were 30 °C and 6.5, respectively. The optimum carbon and nitrogen sources were rice and peptone, respectively. The usefulness of the pigment produced as a food colorant was evaluated by testing for contamination by the harmful mycotoxin citrinin and assessing its biosafety in mice. In addition, sensory evaluation tests were performed to evaluate the overall acceptance of the pigment as a food colorant. The results showed that M. ruber OMNRC45 was able to rapidly and effectively produce dense natural red pigment under the conditions of submerged fermentation without citrinin production. The findings of the sensory and biosafety assessments indicated the biosafety and applicability of the red Monascus pigment as a food colorant.

Transfigured Morphology and Ameliorated Production of Six Monascus Pigments by Acetate Species Supplementation in Monascus ruber M7

Monascus species have been used for the production of many industrially and medically important metabolites, most of which are polyketides produced by the action of polyketide synthases that use acetyl-CoA and malonyl-CoA as precursors, and some of them are derived from acetate. In this study the effects of acetic acid, and two kinds of acetates, sodium acetate and ammonium acetate at different concentrations (0.1%, 0.25% and 0.5%) on the morphologies, biomasses, and six major Monascus pigments (MPs) of M. ruber M7 were investigated when M7 strain was cultured on potato dextrose agar (PDA) at 28 °C for 4, 8, 12 days. The results showed that all of the added acetate species significantly affected eight above-mentioned parameters. In regard to morphologies, generally the colonies transformed from a big orange fleecy ones to a small compact reddish ones, or a tightly-packed orange ones without dispersed mycelia with the increase of additives concentration. About the biomass, addition of ammonium acetate at 0.1% increased the biomass of M. ruber M7. With respect to six MPs, all acetate species can enhance pigment production, and ammonium acetate has the most significant impacts. Production of monascin and ankaflavin had the highest increase of 11.7-fold and 14.2-fold in extracellular contents at the 8th day when 0.1% ammonium acetate was supplemented into PDA. Intracellular rubropunctatin and monascorubrin contents gained 9.6 and 6.46-fold at the 8th day, when 0.1% ammonium acetate was added into PDA. And the extracellular contents of rubropunctamine and monascorubramine were raised by 1865 and 4100-fold at the 4th day when M7 grew on PDA with 0.5% ammonium acetate.

CspA regulation of Staphylococcus aureus carotenoid levels and σB activity is controlled by YjbH and Spx.

Staphyloxanthin, a carotenoid in S. aureus, is a powerful antioxidant against oxidative stresses. The crtOPQMN operon driving pigment synthesis is under the control of σB . CspA, a cold shock protein, is known to control σB activity. To ascertain genes that regulate cspA, we screened a transposon library that exhibited reduced cspA expression and pigmentation. We found that the adaptor protein YjbH activates cspA expression. Spx, the redox-sensitive transcriptional regulator and a proteolytic target for YjbH and ClpXP, complexes with αCTD of RNAP prior to binding the cspA promoter to repress cspA activity. Increased cspA expression in trans in the inactive spx C10A mutant of JE2 did not enhance pigment production while it did in JE2, suggesting that cspA is downstream to Spx in pigmentation control. As the staphyloxanthin pigment is critical to S. aureus survival in human hosts, we demonstrated that the cspA and yjbH mutants survived less well than the parent in whole blood killing assay. Collectively, our studies suggest a pathway wherein YjbH and ClpXP proteolytically cleave Spx, a repressor of cspA transcription, to affect σB -dependent carotenoid expression, thus providing a critical link between intracellular redox sensing by Spx and carotenoid production to improve S. aureus survival during infections.

Post-treatment of Fungal Biomass to Enhance Pigment Production

A new post-treatment method of fungal biomass after fermentation is revealed. The post-treatment strategy was utilized to produce pigments as an additional valuable metabolite. Post-treatment included incubation at 95% relative humidity where the effects of harvesting time, light, and temperature were studied. Pigment-producing edible filamentous fungus Neurospora intermedia cultivated on ethanol plant residuals produced 4 g/L ethanol and 5 g/L fungal biomass. Harvesting the pale biomass after 48 h submerged cultivation compared to 24 h or 72 h increased pigmentation in the post-treatment step with 35% and 48%, respectively. The highest pigment content produced, 1.4 mg/g dry fungal biomass, was obtained from washed biomass treated in light at 35 °C whereof the major impact on pigmentation was from washed biomass. Moreover, post-treated biomass contained 50% (w/w) crude protein. The post-treatment strategy successfully adds pigments to pre-obtained biomass. The pigmented fungal biomass can be considered for animal feed applications for domestic animals.

Induction of pigment production through media composition, abiotic and biotic factors in two filamentous fungi

In addition to plant-derived, fungal pigments have become an alternative in respect to synthetic ones. Besides Monascus sp., several pigment-producing fungi do not have culture conditions well-established yet. In this research, media composition, light wavelength and co-culture were evaluated, results were reported in Absorbance Units per gram of biomass (AU/Bgr). For Fusarium oxysporum a C:N ratio above 7 was advantageous, using both complex and defined media; blue LED light increased the AU/Bgr value from 18013 to 344; co-culture did not enhance pigment production. In Aspergillus chevalieri a high C:N ratio with glucose as carbon source was ideal. When exposing cultures to light, UV and red light gave the highest pigmentation; moreover, differential UV-VIS spectra in all wavelengths suggested production of additional pigments. Particularly a pigment observed when cultured in green light was also found in co-culture with yeast and there was an improvement of AU/Bgr value of 52549%. This is the first report regarding light effect and co-culture for these fungi, as well as C:N ratio for A. chevalieri.

A novel organic dye-based approach to increase photon flux density for enhanced microalgal pigment production

Abstract Numerous research efforts have channeled toward microalgal cultivation systems due to their potential benefit in several applications. Microalgae utilize specific wavelengths of light for photosynthesis. Manipulation of incident irradiance could increase light availability to algae which could enhance pigment production. This study sought to enhance light availability to Chlamydomonas reinhardtii using organic dyes as light converters, thereby improving microalgal pigment production. Diphenylanthracene, Diphenyloxazole, Rhodamine 8G and Lumogen yellow were evaluated at varying concentrations in methanol, ethanol, and acetone. Spectrophotometric analyses revealed that most of the dyes had higher fluorescent intensities in methanol at 10 mgL−1. Lumogen yellow exhibited the highest areal intensity but did not increase biomass production. Rhodamine 8G grown algae increased chlorophyll and carotenoid concentrations by 45 wt% and 36 wt%, respectively. Light stress was observed by increased non-photochemical quenching from approximately 0.05 to above 0.5 and decreased quantum efficiencies of photosystem 2. This novel light manipulation strategy will potentially enable more economical production of high-value microalgal bioproducts using natural sunlight as opposed to artificial light.

Absence of Protoheme IX Farnesyltransferase CtaB Causes Virulence Attenuation but Enhances Pigment Production and Persister Survival in MRSA.

The membrane protein CtaB in S. aureus is a protoheme IX farnesyltransferase involved in the synthesis of the heme containing terminal oxidases of bacterial respiratory chain. In this study, to assess the role of CtaB in S. aureus virulence, pigment production, and persister formation, we constructed a ctaB mutant in the methicillin-resistant Staphylococcus aureus (MRSA) strain USA500. We found that deletion of ctaB attenuated growth and virulence in mice but enhanced pigment production and formation of quinolone tolerant persister cells in stationary phase. RNA-seq analysis showed that deletion of ctaB caused decreased transcription of several virulence genes including RNAIII which is consistent with its virulence attenuation. In addition, transcription of 20 ribosomal genes and 24 genes involved in amino acid biosynthesis was significantly down-regulated in the ctaB knockout mutant compared with the parent strain. These findings suggest the importance of heme biosynthesis in virulence and persister formation of S. aureus.

Cytotoxic potential of a pigment from Serratia marcescens against HepG2 and Jurkat cell lines and optimization of culture conditions for enhanced pigment production

Background: Pigment from micro-organism is one of the emerging areas of research and many pigments have beenextensively studied for their therapeutic potential. Methodology: Our aim was to analyze the anticancer property of ared pigment extracted from Serratia marcescens JGI 27against HepG2 and Jurkat cell lines. The cell viability wasevaluated by MTT assay. As the red pigment extracted from S. marcescens exhibited high cytotoxicity to the testedcancer cell lines, the pigment production was optimized under various culture conditions like, temperature shock,incubation time, carbon sources, nitrogen sources and metal ions. Pigment yield was analyzed spectrophotometricallyat 487 nm. Results: The IC50 value of the red pigment was calculated around &lt; 20μg/mL concentration. Thepercentage viability of lymphocytes and CHO was found to be negligible at all the selected concentration even after72 hrs of incubation. When the bacterial culture was kept at 37°C for 48 hrs and then 50°C for 48 hrs, the yield of thepigment was found to be highest. Supplimentation of sucrose (1%), beef extract (1%) and Fecl30. 01% resulted inenhanced pigment production from S. marcescens JGI 27. Supplementation with the metal ions with at concentrationresulted in highest pigment production. Conclusion: It is concluded that red pigment from S. marcescens JGI 27 wasfound to have a promising cyotoxic effect against HepG2 and Jurkat cell lines and it is non-toxic to normal peripheralhuman lymphocytes and CHO cell lines. At optimum physical and cultural parameters the pigment production wasfound to be highest.

Pseudomonas aeruginosa displays an altered phenotype in vitro when grown in the presence of mannitol

ABSTRACTD-mannitol has been approved in dry powder formulation as an effective antimucolytic agent in patients with cystic fibrosis. What is not known is the effect of adding a metabolisable sugar on the biology of chronic bacterial pathogens in the CF lung. Therefore, a series of simple in vitro experiments were performed to examine the effect of adding D-mannitol on the phenotype of the CF respiratory pathogens Pseudomonas aeruginosa and Burkholderia cenocepacia. Clinical isolates (n=86) consisting of P aeruginosa (n=51), B. cenocepacia (n=26), P. putida (n=4), Stenotrophomonas maltophila (n=3) and Pseudomonas spp. (n=2) were examined by supplementing basal nutrient agar with varying concentrations of D-mannitol (0–20% [w/v]) and subsequently examining for any change in microbial phenotype. The effect of supplementation with mannitol was four-fold, namely i) To increase the proliferation and increase in cell density of all CF organisms examined, with an optimal concentration of 2–4% (w/v) D-mannitol. No such increase in cell proliferation was observed when mannitol was substituted with sodium chloride. ii) Enhanced pigment production was observed in 2/51 (3.9%) of the P. aeruginosa isolates examined, in one of the P. putida isolates, and in 3/26 (11.5%) of the B. cenocepacia isolates examined. iii). When examined at 4.0% (w/v) supplementation with mannitol, 11/51 (21.6%) P. aeruginosa isolates and 3/26 (11.5%) B. cenocepacia isolates were seen to exhibit the altered adhesion phenotype. iv). With respect to the altered mucoid phenotype, 5/51 (9.8%) P. aeruginosa produced this phenotype when grown at 4% mannitol. Mucoid production was greatest at 4%, was poor at 10% and absent at 20% (w/v) mannitol. The altered mucoid phenotype was not observed in the B. cenocepacia isolates or any of the other clinical taxa examined. Due consideration therefore needs to be given, where there is altered physiology within the small airways, leading to a potentially altered biological state of the colonising microorganisms in novel inhaled pharmaceutical interventions in CF, particularly those, which are not designated as antimicrobial agents.

Corncob hydrolysate, an efficient substrate for Monascus pigment production through submerged fermentation

AbstractMonascus pigment has traditionally been produced by the fermentation of Monascus using rice powder or glucose as a culture substrate. Submerged fermentation can produce stable Monascus pigment yield and control the accumulation of the by‐product, citrinin, which can then be more easily removed. To reduce the cost of Monascus submerged fermentation, the feasibility of corncob hydrolysate as an alternative substrate was investigated. Results showed that, when compared with a conventional glucose medium, the corncob hydrolysate medium produced an equivalent pigment yield without stimulating citrinin accumulation. Furthermore, the corncob hydrolysate medium and cultivation conditions were optimized to enhance pigment production and decrease citrinin synthesis. When Monascus sp. was cultured under dark conditions in the presence of caprylic acid, pigment production was increased to 25.8 ± 0.8 UA500/mL, which was higher than that achieved in a glucose medium (24.0 ± 0.9 UA500/mL), and those obtained in previously reported Monascus submerged fermentations using the same yield unit; on the other hand, citrinin accumulation was decreased to 26.2 ± 1.9 µg/L, which was significantly lower than that generated in the glucose control (44.3 ± 2.2 µg/L) and in those previously reported fermentations. Thus, corncob hydrolysate was proved to be an efficient alternative substrate for Monascus pigment production through submerged fermentation, which showed significant advantages over a conventional glucose substrate.

Enhanced production of pigments by addition of surfactants in submerged fermentation of Monascus purpureus H1102

The production of pigments by Monascus spp. has attracted increasing attention. Modification of the cell membrane structure by addition of surfactants has proved to be effective for the secretion of intracellular metabolites. Hence in this study the effects and underlying mechanism of surfactants on the production of pigments in submerged fermentation of Monascus purpureus H1102 were systematically investigated. Various surfactants exerted significant but different impacts on the biomass and production of pigments. The maximum production of pigment (304.3 U mL(-1) ) and highest extracellular/intracellular pigment ratio (1.46) were achieved when 15 g L(-1) Triton X-100 was added at 24 h of fermentation, corresponding to significant increases of 88.4 and 240% respectively compared with the control. Meanwhile, the concentration of citrinin (0.94 mg L(-1) ) was 20.6% lower than that of the control. A further study on the fatty acid composition of M. purpureus H1102 showed that the unsaturated/saturated fatty acid ratio and the index of unsaturated fatty acid increased significantly with the addition of Triton X-100. The addition of surfactant Triton X-100 could greatly enhance the production of pigment. It was suggested that Triton X-100 facilitated the secretion of intracellular pigment and therefore enhanced pigment production accordingly.

Use of several waste substrates for carotenoid-rich yeast biomass production

Carotenoids are industrially significant pigments produced in many bacteria, fungi, and plants. Carotenoid biosynthesis in yeasts is involved in stress response mechanisms. Thus, controlled physiological and nutrition stress can be used for enhanced pigment production. Huge commercial demand for natural carotenoids has focused attention on developing of suitable biotechnological techniques including use of liquid waste substrates as carbon and/or nitrogen source. In this work several red yeast strains (Sporobolomyces roseus, Rhodotorula glutinis, Rhodotorula mucilaginosa) were enrolled into a comparative screening study. To increase the yield of these pigments at improved biomass production, several types of exogenous as well as nutrition stress were tested. Each strain was cultivated at optimal growth conditions and in medium with modified carbon and nitrogen sources. Synthetic media with addition of complex substrates (e.g. yeast extract) and vitamin mixtures as well as some waste materials (whey, potato extract) were used as nutrient sources. Peroxide and salt stress were applied too. The production of carotene enriched biomass was carried out in flasks as well as in laboratory fermentor. The best production of biomass was obtained in inorganic medium with yeast extract. In optimal conditions tested strains differ only slightly in biomass production. All strains were able to use most of waste substrates. Biomass and pigment production was more different according to substrate type. In laboratory fermentor better producers of enriched biomass were both Rhodotorula strains. The highest yields were obtained in R. glutinis CCY 20-2-26 cells cultivated on whey medium (cca 45 g per liter of biomass enriched by 46 mg/L of beta-carotene) and in R. mucilaginosa CCY 20-7-31 grown on potato medium and 5% salt (cca 30 g per liter of biomass enriched by 56 mg/L of beta-carotene). Such dried carotenoid-enriched red yeast biomass could be directly used in feed industry as nutrition supplement.

Growth conditions influence melanization of Brazilian clinical Sporothrix schenckii isolates

Sporothrix schenckii is known to produce DHN melanin on both conidial and yeast cells, however little information is available regarding the factors inducing fungal melanization. We evaluated whether culture conditions influenced melanization of 25 Brazilian S. schenckii strains and one control strain (ATCC 10212). Tested conditions included different media, pH, temperature, incubation time, glucose concentrations, and presence or absence of tricyclazole or L-DOPA. Melanization was reduced on Sabouraud compared to defined chemical medium. The majority of strains produced small amounts of melanin at 37 °C and none melanized at basic pH. Increased glucose concentrations did not inhibit melanization, rather increasing glucose enhanced pigment production in 27% of strains. Melanin synthesis was also enhanced by the addition of L-DOPA and its addition to medium with tricyclazole, an inhibitor of melanin synthesis, resulted in fungal melanization, including hyphal melanin production. Our results suggest that different S. schenckii strains have distinct control of melanization and that this fungus can use phenolic compounds to enhance melanization in vitro.

Enhanced Anthocyanin Production from Grape Callus in an Air-Lift Type Bioreactor Using a Viscous Additive-Supplemented Medium

An N-medium containing carboxymethyl cellulose (CMC) was applied to an air-lift type bioreactor culture of grape (Vitis vinifera cv. Bailey alicant A.) callus, and anthocyanin production was investigated. Grape callus grew well at an air flow rate of 80 ml/min and anthocyanin production was significantly increased in the N-medium, reaching 17 mg/l after 7 d of culture. The anthocyanin content of the N-medium was about two times higher than that of the conventional medium without CMC. The effect of air flow rate was also investigated within the range from 40 to 160 ml/min. A twofold increase in anthocyanin content was obtained at all the air flow rates tested in the N-medium. The distribution of grape callus size obtained after 7 d of the bioreactor culture was investigated. The average callus size was 490 mum which was 1.6 times larger than that obtained in the conventional medium. It was found that large calli with a relatively high anthocyanin pigment content were formed in the bioreactor culture using the N-medium. The fluid dynamics in the bioreactor was also investigated at three points (top, middle and bottom) in the bioreactor by laser doppler velocimetry. The average axial velocity of the circulated medium was 0.4 times lower than that of the conventional medium while their average radial velocities were almost the same (zero). The standard deviation of radial velocity fluctuation in the N-medium was also 0.4 times less than that in the conventional medium. These results suggest that turbulent flow occurred in the bioreactor culture using the conventional medium and the degree of turbulent flow decreased significantly when 0.8% CMC was added to the medium to prepare the N-medium. A change of the flow pattern is considered to be the cause of the decrease in hydrodynamic stress, resulting in enhanced pigment production due to the enlargement of the callus.