Photoregulation of the biosynthetic activity of the edible medicinal mushroom Lentinula edodes in vitro.

The findings of the study demonstrate the impact of low-intensity laser and quasi-monochromatic light on the biosynthetic activity of the edible medicinal fungus L. edodes during submerged cultivation. An artificial lighting installation based on matrices of light-emitting diodes (LED) emitting light at 470 nm (blue), 530 nm (green), 650 nm (red), and argon gas laser (488 nm) was used. Irradiation with blue and red LED and laser led to a shortening of the lag phase by 2 days and an increase in the mycelial mass. Irradiation with laser light resulted in the highest mycelial mass yield (14.1 g/L) on the 8th day of cultivation. Irradiation in all used wavelength ranges caused an increase in the synthesis of both extracellular and intracellular polysaccharides. Laser light at 488 nm and LED at 470 nm proved to be the most effective. Irradiation with red, green, and blue laser light caused an increase in the total amount of fatty acids in the mycelial mass compared to the control. A significant distinction in qualitative composition was observed: short-chain acids C6‒C12 compounds were produced under red light irradiation, whereas long-chain C20‒C24 were formed under green light irradiation. The most significant changes in the aromatic profile of the mycelial mass and culture liquid were recorded upon irradiation with green light. The content of aromatic components increased 24.6 times in the mycelial mass and 38.5 times in the culture liquid. The results suggest the possibility of using low-intensity quasi-monochromatic light for targeted regulation of L. edodes biosynthetic activity.

Inhibition of Aspergillus oryzae Mycelium Growth and Conidium Production by Irradiation with Light at Different Wavelengths and Intensities.

Aspergillus oryzae is a safe filamentous fungus widely used in the food, medicine, and feed industries, but there is currently not enough research on the light response of A. oryzae. In this study, 12 different light conditions were set and A. oryzae GDMCC 3.31 was continuously irradiated for 72 h to investigate the effect of light on mycelial growth and conidium production. Specifically, each light condition was the combination of one light wavelength (475, 520, or 630 nm) and one light intensity (20, 40, 60, or 80 µmol photon m-2 s-1). The results show that mycelium growth was inhibited significantly by green light (wavelength of 520 nm and intensities of 20 and 60 µmol photon m-2 s-1) and blue light (wavelength of 475 nm and intensity of 80 µmol photon m-2 s-1). The production of conidia was suppressed only by blue light (wavelength of 475 nm and intensities of 40, 60, and 80 µmol photon m-2 s-1), and those levels of inhibition increased when the intensity of blue light increased. When the strain was irradiated by blue light (80 µmol photon m-2 s-1), the number of conidia was 57.4% less than that of the darkness group. However, within our set range of light intensities, A. oryzae GDMCC 3.31 was insensitive to red light (wavelength of 630 nm) in terms of mycelium growth and conidium production. Moreover, interaction effects between light wavelength and intensity were found to exist in terms of colony diameter and the number of conidia. This research investigated the light response of A. oryzae, which may provide a new method to regulate mixed strains in fermented foods by light. IMPORTANCE Studies on the monochromatic light response of Aspergillus nidulans and Neurospora crassa have gone deep into the molecular mechanism. However, research methods for the light response of A. oryzae remain in the use of white light sources. In this study, we first demonstrated that A. oryzae GDMCC 3.31 was sensitive to light wavelength and intensity. We have observed that blue light inhibited its growth and sporulation and the inhibitory effect increased with intensity. This research not only adds new content to the study of the photoreaction of Aspergillus but also brings new possibilities for the use of light to regulate mixed strains and ultimately improve the flavor quality of fermented foods.

Enhanced Mycelium Production of Phellinus igniarius (Agaricomycetes) Using a He-Ne Laser with Pulsed Light.

This study used a He-Ne laser with pulsed light irradiation to produce mutant strains of Phellinus igniarius strain JQ9 with enhanced characteristics for fermentation (17.685 ± 3.092 g/L) compared with the parent strain (12.062 ± 1.119 g/L). The combined treatment conditions were as follows: He-Ne laser irradiation for 30 min using a spot diameter of 10 mm, pulsed light treatment power set at 100 J, a treatment distance of 14.5 cm, and a flash frequency of 0.5 s. The production of bioactive polysaccharides and small biocompounds such as polyphenols, flavonoids, and triterpenes increased together with mycelium production. The results showed that polyphenol content was significantly correlated with L*, a*, and b* values (R = -0.594, P < 0.01; R = 0.571, P < 0.01; and R = 0.500, P < 0.05; respectively). Antagonistic and random amplified polymorphic DNA analyses indicated that the genetic material of the screened mutants was altered. The mutant screening using a He-Ne laser with pulsed light irradiation could be an effective method for the development of Phellinus strains and could thus improve mycelium production.

Effect of the oscillating magnetic field on airborne fungal.

This study shows that some species of fungi are affected by the magnetic field, which should be taken into account in studies of airborne fungal and air quality. The aim of this paper was to evaluate the effect of the oscillating magnetic field (OMF) on the behavior of colonies of three fungi genus growth in different culture mediums. The stains were: Aspergillus niger, Cladosporium cladosporioides and Penicillium citrinum and were inoculated in 90 mm Petri dishes with: Malt Extract Agar (MEA), Sabouraud Dextrose Agar (SDA) and Czapek-Dox Agar (CDA). Was applied them OMF of 60 Hz/220 V between 1 and 5 mT during 2 h and then they were incubated 7 days to 28 °C. Colonies size (mm) every day was measured. Stimulation in the colonies size of all experimental conditions was showed; the greatest size of A. niger in MEA was notorious. It was demonstrated by statist analyze that only colonies size with 1 mT was significance respect to the control. The effect of OMF on the cellular metabolism was evidenced, as well as: less exudation and major pigmentation of P. citrinum in MEA; variation of pigmentation of A. niger and C. cladosporioides in CDA and increase of conidiogenesis of A. niger in SDA. Was concluded that the applied OMF had a major influence on size colony and mycelia pigmentation of A. niger that C. cladosporioides and P. citrinum, independently of the nutritional state according to the culture medium employed in this study.

A high-molecular weight exopolysaccharide from the Cs-HK1 fungus: Ultrasonic degradation, characterization and in vitro fecal fermentation.

This work was to examine the impact of power ultrasound (US) on the molecular properties of a high-molecular weight (MW) exopolysaccharide (EPS) from the Cs-HK1 medicinal fungus and the utilization, and prebiotic function of the US-treated EPS fractions in human fecal microflora in vitro. The US treatment caused notable reduction of intrinsic viscosity, average MW and aggregate size of EPS in water but no significant changes in the molecular structure. The US-treated EPS fractions were consumed more rapidly by the fecal microflora, resulting in a higher total level of short chain fatty acids. They also affected the relative abundance in the microflora more beneficially than the original EPS. The results suggest that power US is effective for modifying and improving the prebiotic properties of high-MW polysaccharides.

Combined Effect of Light and Nutrients on the Micromorphology of the White rot Fungus Cerrena Unicolor.

Light influences developmental pathways in fungi. Recent transcriptomic and biochemical analyses have demonstrated that light influences the metabolism of a white-rot basidiomycete Cerrena unicolor. However, the expression profile of genes involved in the growth and development, or micromorphological observations of the mycelium in response to variable lighting and culturing media, have not performed. We aim to reveal the effect of light and nutrients on C. unicolor growth and a potential relationship between the culture medium and lighting conditions on fungus micromorphological structures. Confocal laser scanning microscopy and scanning electron microscopy were employed for morphological observations of C. unicolor mycelium cultivated in red, blue, green, and white light and darkness on mineral and sawdust media. A comprehensive analysis of C. unicolor differentially expressed genes (DEGs) was employed to find global changes in the expression profiles of genes putatively involved in light-dependent morphogenesis. Both light and nutrients influenced C. unicolor growth and development. Considerable differences in the micromorphology of the mycelia were found, which were partially reflected in the functional groups of DEGs observed in the fungus transcriptomes. A complex cross-interaction of nutritional and environmental signals on C. unicolor growth and morphology was suggested. The results are a promising starting point for further investigations of fungus photobiology.

Differential regulation of mycelial growth and aflatoxin biosynthesis by Aspergillus flavus under different temperatures as revealed by strand-specific RNA-Seq.

Although several regulatory pathways have been reported for Aspergillus flavus, the regulation of aflatoxin production and mycelial growth under different temperatures remains unclear. In this study, A. flavus differentially expressed genes (DEGs) and regulatory pathways were analyzed under three temperatures, by strand-specific RNA-Seq. Results show that a total of 2,428 and 1,474 DEGs were identified in fungal mycelia cultured at 20°C and 37°C, respectively, as compared with the control (28°C). Approximately ~ 79% of DEGs in the 37°C samples were up-regulated genes, while ~ 63% of DEGs in the 20°C samples were down-regulated genes. Most of the DEG pathways enriched by lower temperatures differed from those enriched by higher temperatures, while only a small portion of the pathways were shared by A. flavus grown under different temperatures. Aflatoxin biosynthesis, Butanoate metabolism, oxidation-reduction process, and benzene-containing compound metabolic process were the shared down-regulated pathways, while steroid biosynthesis, oxidoreductase activity, cellular protein modification process, DNA binding, protein complex were the shared up-regulated pathways between lower and higher temperatures. The shared genes and pathways are the key regulatory candidates for aflatoxin biosynthesis with changes of temperature. In addition, the identification of both up-regulated and down-regulated genes provides a useful gene set for further investigation of the aflatoxin biosynthesis among Aspergillus.

Effects of cold plasma, UV-C or aqueous ozone treatment on Botrytis cinerea and their potential application in preserving blueberry.

AIMS: This study aimed to compare the effects of cold plasma (CP), ultraviolet (UV-C) and aqueous ozone (AO) on Botrytis cinerea and explore their application in preserving blueberry. METHODS AND RESULTS: The effects of CP, UV-C or AO on B. cinerea were investigated. Results showed that three treatments effectively inhibited the growth of B. cinerea, increasing cell membrane penetrability and causing the leakage of cytoplasm and nucleic acid. Scanning electron microscopy showed that CP caused the mycelium fold and collapse depression; UV-C caused the mycelium shrivelled; mycelium treated with AO appeared to fold and break. In the in vivo test in blueberry, all treatments effectively inhibited the growth of micro-organisms, maintained qualities and enhanced antioxidant activities in blueberry during postharvest storage. CONCLUSION: Cold plasma, UV-C and AO effectively inhibited the growth of B. cinerea and significantly extended the shelf life of blueberry. Based on in vitro and in vivo tests, CP showed better effects to preserve blueberry compared with other treatments. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings revealed the effective mechanisms of CP, UV-C and AO to inhibit B. cinerea in vitro. CP exhibited better application potential to preserve fresh fruit than traditional sterilization methods such as UV-C and AO.

Comparative transcriptome analysis identified candidate genes involved in mycelium browning in Lentinula edodes.

BACKGROUND: Lentinula edodes is one of the most popular edible mushroom species in the world and contains useful medicinal components, such as lentinan. The light-induced formation of brown film on the vegetative mycelial tissues of L. edodes is an important process for ensuring the quantity and quality of this edible mushroom. To understand the molecular mechanisms underlying this critical developmental process in L. edodes, we characterized the morphological phenotypic changes in a strain, Chamaram, associated with abnormal brown film formation and compared its genome-wide transcriptional features. RESULTS: In the present study, we performed genome-wide transcriptome analyses of different vegetative mycelium growth phenotypes, namely, early white, normal brown, and defective dark yellow partial brown films phenotypes which were exposed to different light conditions. The analysis revealed the identification of clusters of genes specific to the light-induced brown film phenotypes. These genes were significantly associated with light sensing via photoreceptors such as FMN- and FAD-bindings, signal transduction by kinases and GPCRs, melanogenesis via activation of tyrosinases, and cell wall degradation by glucanases, chitinases, and laccases, which suggests these processes are involved in the formation of mycelial browning in L. edodes. Interestingly, hydrophobin genes such as SC1 and SC3 exhibited divergent expression levels in the normal and abnormal brown mycelial films, indicating the ability of these genes to act in fruiting body initiation and formation of dikaryotic mycelia. Furthermore, we identified the up-regulation of glycoside hydrolase domain-containing genes in the normal brown film but not in the abnormal film phenotype, suggesting that cell wall degradation in the normal brown film phenotype is crucial in the developmental processes related to the initiation and formation of fruiting bodies. CONCLUSIONS: This study systematically analysed the expression patterns of light-induced browning-related genes in L. edodes. Our findings provide information for further investigations of browning formation mechanisms in L. edodes and a foundation for future L. edodes breeding.

Blue light exposure and nutrient conditions influence the expression of genes involved in simultaneous hyphal knot formation in Coprinopsis cinerea.

Light and nutrients are crucial environmental factors influencing fungal sexual reproduction. Blue light induces simultaneous hyphal knot formation in Coprinopsis cinerea mycelia grown on low-glucose media but not in mycelia grown on high-glucose media. Many hyphal knots are visible in the arc near the edge of the colony one day after 15 min of blue light stimulation. These findings collectively suggest that blue light accelerates hyphal knot induction in nutrient-limited conditions. Transcriptome analysis revealed that gene expression after light exposure is divided into at least two major stages. In the first stage, genes coding for fasciclin (fas1), cyclopropane-fatty-acyl-phospholipid synthases (cfs1 and cfs2), and putative lipid exporter (nod1) are highly expressed after 1 h of light exposure in the mycelial region where the hyphal knot will be developed. These genes are upregulated by blue light and not influenced by glucose condition and mating. These results suggest that although some of the genes are critical for induction of the hyphal knots, they are not sufficient for hyphal knot development. In the second gene expression stage, genes encoding galectins (cgl1-3), farnesyl cysteine-carboxyl methyltransferases, mating pheromone-containing protein, nucleus protein (ich1), and laccase (lcc1) are specifically upregulated at 10-16 h after blue light exposure when the mycelia are cultivated on low-glucose media. These genes might be involved in the architecture of hyphal knots or signal transduction for further fruiting body development. These results contribute to the understanding of the effect of environmental factors on sexual reproduction in basidiomycetous fungi.

Culture conditions and nutrition requirements for the mycelial growth of Isaria farinosa (Hypocreales: Cordycipitaceae) and the altitude effect on its growth and metabolome.

Isaria farinosa is a pathogen of alpine Thitarodes larvae that are hosts for the Chinese medicinal fungus, Ophiocordyceps sinensis. A matrix analysis indicated that the optimal culture conditions for the mycelial growth of I. farinosa are a 50-mL liquid broth in a 250-mL flask at more than 100-rpm rotation and 15-25 °C. Illumination does not affect the mycelial growth. The optimal nutrition requirements are D-(+)-galactose and D-(-)-fructose as carbon resources and D-cysteine as well as yeast powder, peptone, and beef extract as nitrogen resources at a carbon-to-nitrogen ratio of 1:1 to 1:7. The mineral component and vitamins also significantly increase the mycelial growth of I. farinosa. Based on the optimal culture conditions and nutrition requirements for the mycelial growth of I. farinosa, the effects of altitude on mycelial growth and its metabolome were evaluated using quadrupole-time-of-flight/mass spectrometry, principal component analysis and partial least squares discriminant analysis. The altitude did not affect the mycelial production but significantly regulated its metabolome. The study presents a new approach to better select a method for producing more useful metabolites and highlights the necessity of establishing standards for culturing methods related to altitude to preserve fungal quality; additionally, the results indicate that the use of a fermenter may meet the demands of large-scale mycelial production.

Phenolic Compounds of Inonotus rheades (Agaricomycetes) Mycelium: RP-UPLC-DAD-ESI/MS Profile and Effect of Light Wavelength on Styrylpyrone Content.

The phenolic compounds of Inonotus rheades (Pers.) Bondartsev and Singer (Hymenochaetaceae), a typical xylotrophic basidiomycete, and accumulation of styrylpyrones in mycelium under the influence of light of different wavelengths were investigated. Six styrylpyrones (cis- and trans-hispidin, cis- and trans-bisnoryangonin, and phellinins A1 and A2) and 5 bis(styrylpyrones) (3,14'-bishispidinyl, hypholomin B, 3-bisnoryangonyl-14'-hispidin, 1,1-distyrylpyrylethane, and rheadinin) were detected in the extract of I. rheades mycelium using reversed phase ultra-performance liquid chromatography with diode array detection and electrospray ionization mass spectrometry (RP-UPLC-DAD-ESI/MS). The results showed that the maximal content of styrylpyrones was observed under the influence of blue light (8.10 mg/g of dry mycelium weight). Moreover, hispidin was the dominant compound in all experimental groups. Pigmentation intensity gradually decreased after shifting the light spectrum into darkness. It can be concluded that cultivation of I. rheades mycelium under the blue part of the light spectrum leads to the accumulation of styrylpyrones that have nutraceutical and medicinal significance.

Cryopreservation at -75 °C of Agaricus subrufescens on wheat grains with sucrose

Abstract Agaricus subrufescens is a basidiomycete which is studied because of its medicinal and gastronomic importance; however, less attention has been paid to its preservation. This study aimed to evaluate the effect of sucrose addition to substrate and cryotube on the viability of Agaricus subrufescens cryopreserved at -20 °C and at -75 °C for one and two years. Zero, 10% or 20% sucrose was added to potato dextrose agar or wheat grain. The mycelia were cryopreserved in the absence of cryoprotectant or with sucrose solutions at 15%, 30% or 45%. After one or two years at -75 °C or at -20 °C, mycelia were thawed and evaluated about viability, initial time of growth, colony diameter and genomic stability. Cryopreservation at -20 °C is not effective to keep mycelial viability of this fungus. Cryopreservation at -75 °C is effective when sucrose is used in substrates and/or cryotubes. Without sucrose, cryopreservation at -75 °C is effective only when wheat grains are used. Physiological characteristic as mycelial colony diameter is negatively affected when potato dextrose agar is used and unaffected when wheat grain is used after two-year cryopreservation at -75 °C. The fungus genome does not show alteration after two-year cryopreservation at -75 °C.

Improved hypocrellin A production in Shiraia bambusicola by light-dark shift.

Hypocrellin A (HA) is a major bioactive perylenequinone from the fruiting body of Shiraia bambusicola used for the treatment of skin diseases and developed as a photodynamic therapy (PDT) agent against cancers and viruses. The mycelial culture of S. bambusicola under dark is a biotechnological alternative for HA production but with low yield. In this study, light and dark conditions were investigated to develop effective elicitation on HA production in the cultures. Our results showed the constant light at 200 lx stimulated HA production without any growth retardation of mycelia. A light/dark shift (24: 24 h) not only increased HA content in mycelia by 65%, but stimulated HA release into the medium with the highest total HA production 181.67 mg/L on day 8, about 73% increase over the dark control. Moreover, light/dark shifting induced the formation of smaller and more compact fungal pellets, suggesting a new effective strategy for large-scale production of HA in mycelium cultures. The light/dark shift up-regulated the expression levels of two reactive oxygen species (ROS) related genes including superoxide-generating NADPH oxidase (Nox) and cytochrome c peroxidase (CCP), and induced the generation of ROS. With the treatment of vitamin C, we found that ROS was involved in the up-regulated expression of key biosynthetical genes for hypocrellins and improved HA production. These results provide a basis for understanding the influence of light/dark shift on fungal metabolism and the application of a novel strategy for enhancing HA production in submerged Shiraia cultures.

A Comparative Proteome Approach Reveals Metabolic Changes Associated with Flammulina velutipes Mycelia in Response to Cold and Light Stress.

In some industrial processes, cold and light stresses are recognized as two important environmental triggers for the transformation of mycelia into fruit-bodies via intermediate primordia in Flammulina velutipes cultivation. To gain insights into the mechanism of regulation of F. velutipes mycelia in response to cold and light stress, proteins expressed abundantly and characteristically at particular stress states were investigated by using the isobaric tags for the relative and absolute quantitation labeling technique. Among the 1046 nonredundant proteins identified with a high degree of confidence, 264 proteins, which were detected as differentially expressed proteins, were associated with 176 specific KEGG pathways. In-depth data analysis revealed that the regulatory network underlying the cold and light response mechanisms of F. velutipes mycelia was complex and multifaceted, as it included varied functions such as rapid energy supply, the biosynthesis of lysine, phenylalanine, tyrosine, and γ-aminobutyric acid, the calcium signal transduction process, dynein-dependent actin and microtubule cytoskeleton formation, autolysis, oxidative stress adaptation, pigment secretion, tissue and organ morphogenesis, and other interesting stress-related processes. Insights into the proteins might shed light on an intuitive understanding of the cold and light stress response mechanism underlying the fruiting processes of F. velutipes. Furthermore, the data might also provide further insights into the stress response mechanism of macro-fungi and valuable information for scientific improvement of some mushroom cultivation techniques in practice.

Photochemical inhibition of Trichophyton rubrum by different compoundings of curcumin.

Recently, we had shown that conidia-derived growth of many dermatophytes can be inhibited by curcumin plus exposure to visible light. This method of photo inactivation should be developed further aiming for an option to stop mycelial growth in superficial tinea. Wells of microtitre plates were inoculated with either mycelial or conidial elements collected from 5 strains of Trichophyton rubrum. Then either micellar curcumin or curcumin dissolved with DMSO was added and after 20 min the wells were filled up with Sabouraud broth. Thereafter the assays were irradiated once with visible light (wave length 420 nm, 20 J/cm2 ) and fungal growth was monitored photometrically. Identical effects were measured with conidia and mycelial elements of all 5 T. rubrum strains. Curcumin dissolved with DMSO plus irradiation had a marked dose-dependent inhibitory effect on fungal growth that was almost complete with 5.0 mg/L (P < .01) over a period of 9 days. In contrast, the same procedure with micellar curcumin had no inhibitory effect on growth obtained from conidia or mycelial elements. Mycelial elements of T. rubrum and its conidia are equally sensitive to photochemical inactivation with curcumin and the galenic compounding of curcumin is essential to achieve this photochemical effect.

Cryopreservation at -75°C of Agaricus subrufescens on wheat grains with sucrose.

Agaricus subrufescens is a basidiomycete which is studied because of its medicinal and gastronomic importance; however, less attention has been paid to its preservation. This study aimed to evaluate the effect of sucrose addition to substrate and cryotube on the viability of Agaricus subrufescens cryopreserved at -20°C and at -75°C for one and two years. Zero, 10% or 20% sucrose was added to potato dextrose agar or wheat grain. The mycelia were cryopreserved in the absence of cryoprotectant or with sucrose solutions at 15%, 30% or 45%. After one or two years at -75°C or at -20°C, mycelia were thawed and evaluated about viability, initial time of growth, colony diameter and genomic stability. Cryopreservation at -20°C is not effective to keep mycelial viability of this fungus. Cryopreservation at -75°C is effective when sucrose is used in substrates and/or cryotubes. Without sucrose, cryopreservation at -75°C is effective only when wheat grains are used. Physiological characteristic as mycelial colony diameter is negatively affected when potato dextrose agar is used and unaffected when wheat grain is used after two-year cryopreservation at -75°C. The fungus genome does not show alteration after two-year cryopreservation at -75°C.

Effect of Pulsed Light Irradiation on Bioactive, Nonvolatile Components and Antioxidant Properties of Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes).

The caterpillar medicinal mushroom Cordyceps militaris contains many bioactive components, such as adenosine, cordycepin, and polysaccharides. In this study, C. militaris was exposed to 0, 3, 6, or 9 pulses of light irradiation to estimate changes in vitamin D2, bioactive compounds, nonvolatile taste components, and antioxidant properties. In addition, we compared the components and properties of C. militaris mycelia and solid waste medium that had been treated with pulsed light (PL) irradiation. Overall, PL irradiation of C. militaris increased the vitamin D2 content and increased the total amino acid levels 9-48%; the antioxidant properties of the mycelia treated with 0 pulses and of the solid waste medium treated with 3 pulses all exhibited lower half-maximal effective concentrations. Therefore, PL irradiation affected the amounts of bioactive compounds, but the irradiated samples still contained intense umami taste and a sufficient amount of antioxidant components.

Significance of Heavy-Ion Beam Irradiation-Induced Avermectin B1a Production by Engineered Streptomyces avermitilis.

Heavy-ion irradiation technology has advantages over traditional methods of mutagenesis. Heavy-ion irradiation improves the mutation rate, broadens the mutation spectrum, and shortens the breeding cycle. However, few data are currently available regarding its effect on Streptomyces avermitilis morphology and productivity. In this study, the influence of heavy-ion irradiation on S. avermitilis when cultivated in approximately 10 L stirred-tank bioreactors was investigated. The specific productivity of the avermectin (AVM) B1a-producing mutant S. avermitilis 147-G58 increased notably, from 3885 to 5446 µg/mL, approximately 1.6-fold, compared to the original strain. The mycelial morphology of the mutant fermentation processes was microscopically examined. Additionally, protein and metabolite identification was performed by using SDS-PAGE, 2- and 3-dimensional electrophoresis (2DE and 3DE). The results showed that negative regulation gene deletion of mutants led to metabolic process upregulating expression of protein and improving the productivity of an avermectin B1a. The results showed that the heavy-ion beam irradiation dose that corresponded to optimal production was well over the standard dose, at approximately 80 Gy at 220 AMeV (depending on the strain). This study provides reliable data and a feasible method for increasing AVM productivity in industrial processes.

Performance of microwave treatment for disintegration of cephalosporin mycelial dreg (CMD) and degradation of residual cephalosporin antibiotics.

Significant amounts of cephalosporin mycelial dreg (CMD) are still being generated from biopharmaceutical processes, representing both an economic and environmental burden for pharmaceutical factories. This study investigates the microwave (MW) treatment of CMD at a relatively mild temperature (100°C) within 15min. The results reveal that the MW treatment disintegrates the CMD efficiently and that the residual cephalosporin C (CPC) is almost degraded after sufficient irradiation. MW heating temperature strongly influences the polymer's release. SCOD (soluble chemical oxygen demand), soluble proteins and carbohydrates have significant positive correlations to the temperature (r=0.993, 0.983 and 0.992, respectively; p<0.01). 3D-EEM fluorescence spectra indicate that the key organic matters relate to temperature as well as microwave energies. Furthermore, more than 99.9% of the residual antibiotics in CMD are degraded by MW irradiation without antibacterial activities that are proven by the possible degradation pathway we elucidate. These results suggest that microwave irradiation treatment not only disintegrates CMD and destroys mycelial cells but also degrades the residual cephalosporin antibiotics, which implies the possibility for practical applications.