Novel Catechol O-methyltransferases from Lentinula edodes Catalyze the Generation of Taste-Active Flavonoids.

Due to the increasing demand for natural food ingredients, including taste-active compounds, enzyme-catalyzed conversions of natural substrates, such as flavonoids, are promising tools to align with the principles of Green Chemistry. In this study, a novel O-methyltransferase activity was identified in the mycelium of Lentinula edodes, which was successfully applied to generate the taste-active flavonoids hesperetin, hesperetin dihydrochalcone, homoeriodictyol, and homoeriodictyol dihydrochalcone. Furthermore, the mycelium-mediated OMT activity allowed for the conversion of various catecholic substrates, yielding their respective (iso-)vanilloids, while monohydroxylated compounds were not converted. By means of a bottom-up proteomics approach, three putative O-methyltransferases were identified, and subsequently, synthetic, codon-optimized genes were heterologously expressed in Escherichia coli. The purified enzymes confirmed the biocatalytic O-methylation activity against targeted flavonoids containing catechol motifs.

Enhanced extracellular production of laccase in Coprinopsis cinerea by silencing chitinase gene.

Laccase, a copper-containing polyphenol oxidase, is an important green biocatalyst. In this study, Laccase Lcc5 was homologous recombinantly expressed in Coprinopsis cinerea and a novel strategy of silencing chitinase gene expression was used to enhance recombinant Lcc5 extracellular yield. Two critical chitinase genes, ChiEn1 and ChiE2, were selected by analyzing the transcriptome data of C. cinerea FA2222, and their silent expression was performed by RNA interference (RNAi). It was found that silencing either ChiEn1 or ChiE2 reduced sporulation and growth rate, and increased cell wall sensitivity, but had no significant effect on mycelial branching. Among them, the extracellular laccase activity of the ChiE2-silenced engineered strain Cclcc5-antiChiE2-5 and the control Cclcc5-13 reached the highest values (38.2 and 25.5 U/mL, respectively) at 250 and 150 rpm agitation speeds, corresponding to productivity of 0.35 and 0.19 U/mL·h, respectively, in a 3-L fermenter culture. Moreover, since Cclcc5-antiChiE2-5 could withstand greater shear forces, its extracellular laccase activity was 2.6-fold higher than that of Cclcc5-13 when the agitation speed was all at 250 rpm. To our knowledge, this is the first report of enhanced recombinant laccase production in C. cinerea by silencing the chitinase gene. This study will pave the way for laccase industrial production and accelerate the development of a C. cinerea high-expression system. KEY POINTS: • ChiEn1 and ChiE2 are critical chitinase genes in C. cinerea FA2222 genome. • Chitinase gene silencing enhanced the tolerance of C. cinerea to shear forces. • High homologous production of Lcc5 is achieved by fermentation in a 3-L fermenter.

Evaluation of Laccase Production by Monokaryotic Strains of Edible Mushrooms.

<b>Background and Objective:</b> Edible mushroom laccases are one of the most attractive enzymes applicable in numerous industrial sectors. The purpose of this research is to construct monokaryotic strains from selected isolates of edible mushrooms and to study the effects of inducers on laccase production under solid-state fermentation. <b>Materials and Methods:</b> Isolation of local commercial strains of edible mushrooms was carried out from the pileus region using standard laboratory techniques. The laccase production was carried out using 40 mM 2,6-Dimethoxyphenol (2,6-DMP) and 40 mM guaiacol as substrate. The generation of monokaryotic strains was performed by mycelium homogenization in sterile water and regrowth in an appropriate medium. Laccase production and study of the effects of inducers on laccase production were then studied. <b>Results:</b> Laccase production of native and monokaryotic strains distinguished these strains into three groups: HIGH-(KK24, KK25), MEDIUM-(KK26, KK1, KK5 and KK23) and LOW (KK13, KK8). Reduced activity was found in almost all isolates after 14 days of inoculation. The effect of pure copper sulfate, copper sulfate with DMP, Tween80 and synthetic melanoidin was studied at 7 and 14 days. KK24 and KK25 showed their positive response to all inducers about 1.5-2.5 folds of activity to their native strains. <b>Conclusion:</b> Eight strains of local and commercial mushrooms were isolated and purified. The corresponding monokaryotic strains were generated from chemical dedikaryotization. Studies of laccase production showed that KK24 and KK25 were high laccase producer's throughout the incubation period. The addition of inducers augmented laccase activity in KK24 and KK25 along with their corresponding monokaryotic strains.

Significance of two intracellular triacylglycerol lipases of Aspergillus oryzae in lipid mobilization: A perspective in industrial implication for microbial lipid production.

Microbial lipid production of oleaginous strains involves in a complex cellular metabolism controlling lipid biosynthesis, accumulation and degradation. Particular storage lipid, triacylglycerol (TAG), contributes to dynamic traits of intracellular lipids and cell growth. To explore a basis of TAG degradation in the oleaginous strain of Aspergillus oryzae, the functional role of two intracellular triacylglycerol lipases, AoTgla and AoTglb, were investigated by targeted gene disruption using CRISPR/Cas9 system. Comparative lipid profiling of different cultivation stages between the control, single and double disruptant strains (ΔAotgla, ΔAotglb and ΔAotglaΔAotglb strains) showed that the inactivation of either AoTgla or AoTglb led to the increase of total lipid contents, particularly in the TAG fraction. Moreover, the prolonged lipid-accumulating stage of all disruptant strains was obtained as indicated by a reduction in specific rate of lipid turnover, in which a holding capacity in maximal lipid and TAG levels was achieved. The involvement of AoTgls in spore production of A. oryzae was also discovered. In addition to the significance in lipid physiology of the oleaginous fungi, this study provides an impact on industrial practice by overcoming the limitation in short lipid-accumulating stage of the fungal strain, which facilitate the cell harvesting step at the maximum lipid production yield.

Label-Free Proteomics Reveals the Molecular Mechanism of Subculture Induced Strain Degeneration and Discovery of Indicative Index for Degeneration in Pleurotus ostreatus.

Pleurotus ostreatus is one of the widely cultivated edible fungi across the world. Mycelial subculture is an indispensable part in the process of cultivation and production for all kinds of edible fungi. However, successive subcultures usually lead to strain degeneration. The degenerated strains usually have a decrease in stress resistance, yield, and an alteration in fruiting time, which will subsequently result in tremendous economic loss. Through proteomic analysis, we identified the differentially expressed proteins (DEPs) in the mycelium of Pleurotus ostreatus from different subcultured generations. We found that the DNA damage repair system, especially the double-strand breaks (DSBs), repairs via homologous recombination, was impaired in the subcultured mycelium, and gradual accumulation of the DSBs would lead to the strain degeneration after successive subculture. The TUNEL assay further confirmed our finding about the DNA breaks in the subcultured mycelium. Interestingly, the enzyme activity of laccase, carboxylic ester hydrolase, α-galactosidase, and catalase directly related to passage number could be used as the characteristic index for strain degeneration determination. Our results not only reveal for the first time at the molecular level that genomic instability is the cause of degeneration, but also provide an applicable approach for monitoring strain degeneration in process of edible fungi cultivation and production.

Molecular cloning, characterization, and heterologous expression of an acetyl-CoA acetyl transferase gene from Sanghuangporus baumii.

Acetyl-CoA C-acetyltransferase synthase gene (AACT) cDNA, DNA and promoter were cloned from Sanghuangporus baumii. The gene ORF (1260 bp) encoded 419 amino acids. The AACT DNA includes five exons (1-84 bp, 140-513 bp, 570-1027 bp, 1090-1282 bp, 1344-1494 bp) and four introns (85-139 bp, 514-569 bp, 1028-1089 bp, 1283-1343 bp). The molecular weight of AACT protein is 43.40 kDa, it is hydrophilic with a theoretical isoelectric point of 8.96. Furthermore, The region of the transcription start site is 1997-2047 bp of AACT promoter, and it contained promoter elements (TATA Boxs, CAAT Boxs, CAAT-box, ABRE, G-Boxs, Sp1, MSA-like, LTR). AACT recombinant protein (43.40 KDa + Tag protein 22.68 KDa) was subjected in SDS-PAGE. AACT the transcription levels of in different development stages were investigated. The expression of AACT in primordia (2.4-fold) and 15 d mycelia (2.3- fold) were significantly higher than 9 d mycelia (contral). The expression level of the AACT downstream genes and triterpenoids content were determined at different developmental stages. Triterpenoid content reached its peak on day 15(7.21 mg/g).

The PoV mycovirus affects extracellular enzyme expression and fruiting body yield in the oyster mushroom, Pleurotus ostreatus.

Isogenic virus-cured and virus-infected fungal strains were previously obtained and compared to investigate mycoviral diseases and, specifically, the influence of viral infection on the vegetative growth of Pleurotus ostreatus. The present study demonstrated that infection with mycovirus PoV-ASI2792 (PoV) caused phenotypic and physiological changes in fungal cells and mycelia. The microscopically determined growth rate of the virus-infected strain was lower than that of the virus-cured strain, due to the conglomerate phenomenon during the mycelial growth process. An exploration of the viral effects of PoV on fruiting bodies yield showed significantly lower than that on virus-cured P. ostreatus. A colorimetric assay of polyphenol oxidase activity in the strains showed very weak activity in the virus-infected strain. To estimate the activity levels of enzymes related to the growth and fruiting body formation, the relative expression levels of genes encoding various extracellular enzymes such as Carbohydrate-Active Enzymes (CAZymes) were measured by quantitative RT-PCR. The expression levels of the assayed genes were significantly lower in virus-infected than in virus-cured P. ostreatus. Together, these results indicate that PoV infection affects the spawn growth and fruiting body formation of P. ostreatus via decreased expression and activity of some extracellular enzymes including lignocellulolytic enzymes.

Kinetics Analysis of the Inhibitory Effects of Alpha-Glucosidase and Identification of Compounds from Ganoderma lipsiense Mycelium.

The studies on natural compounds to diabetes mellitus treatment have been increasing in recent years. Research suggests that natural components can inhibit alpha-glucosidase activities, an important strategy in the management of blood glucose levels. In this work, for the first time in the literature, the compounds produced by Ganoderma lipsiense extracts were identified and evaluated on the inhibitory effect of these on alpha-glucosidase activity. Four phenolic compounds were identified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) to crude extract from G. lipsiense grown in red rice medium (RCE) and synthetic medium (SCE), being syringic acid identified in both extracts. Gas chromatography-mass spectrometry (GC-MS) analysis showed fatty acids and their derivatives, terpene, steroid, niacin, and nitrogen compounds to SCE, while RCE was rich in fatty acids and their derivatives. Both extracts demonstrated alpha-glucosidase inhibition (RCE IC50 = 0.269 ± 8.25 mg mL-1; SCE IC50 = 0.218 ± 9.67 mg mL-1), and the purified hexane fraction of RCE (RHEX) demonstrated the highest inhibition of enzyme (81.1%). Studies on kinetic inhibition showed competitive inhibition mode to RCE, while SCE showed uncompetitive inhibition mode. Although the inhibitory effects of RCE and SCE were satisfactory, the present findings identified some unpublished compounds to G. lipsiense in the literature with important therapeutic properties.

Elucidation of the Higher Basidiomycetes Enzyme Activity in Dependence on the Medicinal Mushroom Inoculum Form, Precultivation Medium, Age, and Size.

The impact of five mushroom inoculum form, age, size, and precultivation medium on the lignocellulose-deconstracting enzyme (LCDE) production was evaluated in the submerged fermentation of mandarin marc. The results obtained evidence that an adaptation of individual fungi to lignocellulose during maintenance in culture collection and inoculum cultivation may be useful for the production of individual LCDE. Homogenization of submerged mycelium was beneficial for all LCDE production by Cerrena unicolor 305 and Ganoderna lucidum 447 and for LME secretion by Coriolopsis gallica 142 and Trametes multicolor 511. Finely chopped mycelial agar favored CMCase and xylanase production by T. multicolor 511 and LiP secretion by C. unicolor 305 and G. lucidum 447 while homogenized mycelial agar proved to be the worst form of inoculum for the production of most enzymes. Four-days inoculum was the most appropriate for the laccase and MnP production by G. lucidum 447 and T. multicolor 511 while the 7-days mycelium provided the highest yields of these enzymes in the cultivation of C. unicolor 305. Use of the 12-days homogenized mycelium from the late stationary phase resulted in lowest laccase activity of all fungi but provided the highest cellulase activity. Overall, the study showed that the LCDE activity and their accumulation profiles in the cultures with different inoculum size was species dependent.

The NADPH oxidase in Volvariella volvacea and its differential expression in response to mycelial ageing and mechanical injury.

NADPH oxidases are enzymes that have been reported to generate reactive oxygen species (ROS) in animals, plants and many multicellular fungi in response to environmental stresses. Six genes of the NADPH oxidase complex components, including vvnoxa, vvnoxb, vvnoxr, vvbema, vvrac1 and vvcdc24, were identified based on the complete genomic sequence of the edible fungus Volvariella volvacea. The number of vvnoxa, vvrac1, vvbema and vvcdc24 transcripts fluctuated with ageing, and the gene expression patterns of vvnoxa, vvrac1 and vvbema were significantly positively correlated. However, the expression of vvnoxb and vvnoxr showed no significant difference during ageing. In hyphae subjected to mechanical injury stress, both O2- and H2O2 concentrations were increased. The expression of vvnoxa, vvrac1, vvbema and vvcdc24 was substantially upregulated, but vvnoxb and vvnoxr showed no response to mechanical injury stress at the transcriptional level. Additionally, the transcription of vvnoxa, vvrac1, vvbema and vvcdc24 could be repressed when the intracellular ROS were eliminated by diphenyleneiodonium (DPI) chloride and reduced glutathione (GSH) treatments. These results indicated a positive feedback loop involving NADPH oxidase and intracellular ROS, which might be the reason for the oxidative burst during injury stress.

Distinct enzymatic and cellular characteristics of two phospholipases A1 in Aspergillus oryzae.

Phospholipases A1 (PLA1s) catalyze the hydrolysis of sn-1 linkage in the glycerophospholipids, thereby releasing fatty acids and 2-acyl lysophospholipids. PLA1s are found in various organisms and tissues where they play diverse cellular functions, but their roles in filamentous fungi remain elusive. In this study we analyzed the enzymatic properties and physiological functions of two secretory PLA1s, PLA1-1 and its paralog PLA1-2, in the filamentous fungus Aspergillus oryzae. Although PLA1-1 and PLA1-2 share 49% amino acid sequence identity, they significantly differ in various aspects. While PLA1-1 displayed PLA1 activity to phosphatidylcholine and phosphatidylethanolamine, and degraded various phospholipids, PLA1-2 exhibited PLA1 activity only to phosphatidylglycerol. PLA1-1 was secreted to the culture medium, but PLA1-2 was not secreted and retained in the mycelium. Fluorescence microscopic observation of A. oryzae strains expressing EGFP-fused PLA1-1 and PLA1-2 demonstrated that they display overlapping but distinct cellular localization. A. oryzae mutants deleted for pla1-1 or pla1-2 grew normally, but the secreted phospholipase activity was significantly reduced in the Δpla1-1 strain. These data suggest that two sPLA1 enzymes are not redundant and play distinct cellular functions in A. oryzae.

Purification and characterization of Terfezia claveryi TcCAT-1, a desert truffle catalase upregulated in mycorrhizal symbiosis.

Terfezia claveryi Chatin is a mycorrhizal fungus that forms ectendomycorrhizal associations with plants of Helianthemum genus. Its appreciated edibility and drought resistance make this fungus a potential alternative crop in arid and semiarid areas of the Mediterranean region. In order to increase the knowledge about the biology of this fungus in terms of mycorrhiza formation and response to drought stress, a catalase from T. claveryi (TcCAT-1) has been purified to apparent homogeneity and biochemically characterized; in addition, the expression pattern of this enzyme during different stages of T. claveryi biological cycle and under drought stress conditions are reported. The results obtained, together with the phylogenetic analysis and homology modeling, indicate that TcCAT-1 is a homotetramer large subunit size monofunctional-heme catalase belonging to Clade 2. The highest expression of this enzyme occurs in mature mycorrhiza, revealing a possible role in mycorrhiza colonization, but it is not upregulated under drought stress. However, the H2O2 content of mycorrhizal plants submitted to drought stress is lower than in well watered treatments, suggesting that mycorrhization improves the plant's oxidative stress response, although not via TcCAT-1 upregulation.

Functions of a Glucan Synthase Gene GFGLS in Mycelial Growth and Polysaccharide Production of Grifola frondosa.

Glucan synthase (GLS) gene is known to be involved in the fungal biosynthesis of cell wall, differentiation, and growth. In the present study, a glucan synthase gene (GFGLS) in the edible mushroom Grifola frondosa with a full sequence of 5927 bp encoding a total of 1781 amino acids was cloned and characterized for the first time. GFGLSp is a membrane protein containing two large transmembrane domains connected with a hydrophilic cytoplasmic domain. With a constructed dual promoter RNA silencing vector pAN7-gfgls-dual, a GFGLS-silencing transformant iGFGLS-3 had the lowest GFGLS transcriptional expression level (26.1%) with a shorter length and thinner appearance of the mycelia, as well as decreased mycelial biomass and exo-polysaccharide production of 5.02 and 0.38 g/L, respectively. Further analysis indicated that GFGLS silence influenced slightly the monosaccharide compositions and ratios of mycelial and exo-polysaccharide. These findings suggest that GFGLS could affect mycelial growth and polysaccharide production by downregulating the glucan synthesis.

Characterization of a mycelial fructosyltransferase from Aspergillus tamarii NKRC 1229 for efficient synthesis of fructooligosaccharides.

An efficient system for biotransformation of sucrose to fructooligosaccharides (FOS) was obtained using Aspergillus tamarii NKRC 1229 mycelial fructosyltransferase (m-FTase). Zymographic analysis confirmed mycelial localization of the FTase (36 U/g) and lyophilized fungal pellets were used for bioconversion. m-FTase had molecular weight ∼75 kDa with optimum activity at pH 7.0 and 20 °C. FOS production after parametric optimization (sucrose - 50% w/v, m-FTase dose - 4.5% w/v, inoculum age - 48 h and incubation time - 24 h) reached 325 g/L (55% yield) with 14% residual sucrose, 25% glucose and 6% fructose. FTase activity was enhanced after pre-treatment with organic solvents and SDS. FOS was purified in a single step using gel filtration matrix, Bio-Gel P2. FOS was characterized using Diffusion ordered spectroscopy-Nuclear Magnetic Resonance (1H DOSY-NMR) and Fourier-transform infrared spectroscopy (FTIR). Continuous generation of FOS was achieved using recyclable mycelia upto 10 consecutive cycles.

Identification of a novel chitinase from Aeromonas hydrophila AH-1N for the degradation of chitin within fungal mycelium.

Defined organic waste products are ideal and sustainable secondary feedstocks for production organisms in microbial biotechnology. Chitin from mycelia of fungal fermentation processes represents a homogeneous and constantly available waste product that can, however, not be utilised by typical bacterial production strains. Therefore, enzymes that degrade chitin within fungal mycelia have to be identified and expressed in production organisms. In this study, chitin-degrading bacteria were enriched and isolated from lake water with mycelia of Aspergillus tubingensis as sole organic growth substrate. This approach yielded solely strains of Aeromonas hydrophila. Comparison of the isolated strains with other A. hydrophila strains regarding their chitinolytic activities on fungal mycelia identified strain AH-1N as the best enzyme producer. From this strain, a chitinase (EC:3.2.1.14) was identified by peptide mass fingerprinting. Heterologous expression of the respective gene combined with mass spectrometry showed that the purified enzyme was capable of releasing chitobiose from fungal mycelia with a higher yield than a well-described chitinase from Serratia marcescens. Expression of the newly identified chitinase in biotechnological production strains could be the first step for making fungal mycelium accessible as a secondary feedstock. Additionally, the enrichment strategy proved to be feasible for identifying strains able to degrade fungal chitin.

Characterization and functional analysis of calcium/calmodulin-dependent protein kinases (CaMKs) in the nematode-trapping fungus Arthrobotrys oligospora.

Ca2+/calmodulin-dependent protein kinases (CaMKs) are unique second-messenger molecules that impact almost all cellular processes in eukaryotes. In this study, five genes encoding different CaMKs were characterized in the nematode-trapping fungus Arthrobotrys oligospora. These CaMKs, which were retrieved from the A. oligospora genome according to their orthologs in fungi such as Aspergillus nidulans and Neurospora crassa, were expressed at a low level in vitro during mycelial growth stages. Five deletion mutants corresponding to these CaMKs led to growth defects in different media and increased sensitivity to several environmental stresses, including H2O2, menadione, SDS, and Congo red; they also reduced the ability to produce conidia and traps, thus causing a deficiency in nematicidal ability as well. In addition, the transcriptional levels of several typical sporulation-related genes, such as MedA, VelB, and VeA, were down-regulated in all ΔCaMK mutants compared with the wild-type (WT) strain. Moreover, these mutants exhibited hypersensitivity to heat shock and ultraviolet-radiation stresses compared with the WT strain. These results suggest that the five CaMKs in A. oligospora are involved in regulating multiple cellular processes, such as growth, environmental stress tolerance, conidiation, trap formation, and virulence.

Transcriptome analysis of differential gene expression in Dichomitus squalens during interspecific mycelial interactions and the potential link with laccase induction.

Interspecific mycelial interactions between white rot fungi are always accompanied by an increased production of laccase. In this study, the potential of the white rot fungus Dichomitus squalens to enhance laccase production during interactions with two other white rot fungi, Trametes versicolor or Pleurotus ostreatus, was assessed. To probe the mechanism of laccase induction and the role that laccase plays during combative interaction, we analyzed the differential gene expression profile of the laccase induction response to stressful conditions during fungal interaction. We further confirmed the expression patterns of 16 selected genes by qRT-PCR analysis. We noted that many differentially expressed genes (DEGs) encoded proteins that were involved in xenobiotic detoxification and reactive oxygen species (ROS) generation or reduction, including aldo/keto reductase, glutathione S-transferases, cytochrome P450 enzymes, alcohol oxidases and dehydrogenase, manganese peroxidase and laccase. Furthermore, many DEG-encoded proteins were involved in antagonistic mechanisms of nutrient acquisition and antifungal properties, including glycoside hydrolase, glucanase, chitinase and terpenoid synthases. DEG analyses effectively revealed that laccase induction was likely caused by protective responses to oxidative stress and nutrient competition during interspecific fungal interactions.

Antioxidative and hepatoprotective effects of enzymatic and acidic-hydrolysis of Pleurotus geesteranus mycelium polysaccharides on alcoholic liver diseases.

The present work investigated the antioxidant and hepatoprotective effects of acidic- and enzymatic-hydrolysis mycelium polysaccharide (AcMPS and EnMPS) from Pleurotus geesteranus on alcoholic liver disease (ALD) mice. The animal studies demonstrated that the polysaccharides had potential effects reflected by remitting alcoholic hepatitis, reducing lipid accumulation, preventing oxidative stress, improving inflammatory symptoms, and alleviating the liver functions by histopathologic observation. Results showed that AcMPS (yield of 84%) was composed of L-Rha, D-Rib, L-Ara, D-Glc, D-Man and D-Gal with the Mw of 3.49 × 104 Da, while EnMPS (yield of 90%) was contained L-Rha, L-Ara, D-Gal and D-Glc with the Mw of 3.67 × 104 Da. Furthermore, the GC-MS analysis indicated that both AcMPS and EnMPS were ß-pyranoside polysaccharides with the (1→3)- and (1→6)-linkages. The conclusions indicated that AcMPS and EnMPS could be used as natural drugs for preventing the ALD, and providing underlying hepatoprotective mechanisms, pharmaceutically.

Laccase production and pellet morphology of Coprinopsis cinerea transformants in liquid shake flask cultures.

Laccase production and pellet formation of transformants of Coprinopsis cinerea strain FA2222 of C. cinerea laccase gene lcc1 subcloned behind the gpdII-promoter from Agaricus bisporus were compared with a control transformant carrying no extra laccase gene. At the optimum growth temperature of 37 °C, maximal laccase yields of 2.9 U/ml were obtained by the best lcc1 transformant pYSK7-26 in liquid shake flask cultures. Reduction in temperature to 25 °C increased laccase yields up to 9.2 U/ml. The control transformant had no laccase activities at 37 °C but native activity at 25 °C (3.5 U/ml). Changing the temperature had severe effects on the morphology of the mycelial pellets formed during cultivation, but links of distinct pellet morphologies to native or recombinant laccase production could not be established. Automated image analysis was used to characterise pellet formation and morphological parameters (pellet area, diameter, convexity and mycelial structure). Cross sections of selected pellets showed that they differentiated in an outer rind and an inner medulla of loosened hyphae. Pellets at 25 °C had a small and dense outer zone and adopted with time a smooth surface. Pellets at 37 °C had a broader outer zone and a fringy surface due to generation of more and larger protuberances in the rind that when released can serve for production of further pellets.

Decolorization of mordant yellow 1 using Aspergillus sp. TS-A CGMCC 12964 by biosorption and biodegradation.

In this report, the decolorization features of extracellular enzymes and mycelia separately prepared from Aspergillus sp. TS-A CGMCC 12,964 (120 h) were investigated. The fermentation broth of TS-A degraded 98.6% of Mordant Yellow 1 (50 mg/L) at an initial pH 6 within 1 h with over 70% of the dye (50 mg/L) degraded by extracellular enzymes and 18.8% removed by live mycelia. The degradation products of the dye were analyzed by UV-Vis and FTIR spectra. The decolorization rates of extracellular enzymes and mycelia were examined under different contact periods, dye concentrations and pH values. The extracellular enzymes exhibited excellent degradation activity under weak acidic conditions. In addition, biosorption models of mycelia fitted well the Langmuir isotherm model and the pseudo-second-order kinetic equation. Although the decolorization process was achieved through the synergistic effects of mycelia and extracellular enzymes, decolorization was dominated by the biodegradation activity of the extracellular enzymes from TS-A.