Effect of Glucose on Endo-xylanase and β-xylosidase Production by Fungi Isolated in Indonesia

Xylanases are widely produced by fungi, and the production of polysaccharide-degrading enzymes, in general, are usually subjected to carbon catabolite repression. In this work, the ability of several Indonesian indigenous fungi to produce endo-xylanase and β-xylosidase and their responses to glucose as a repressor were determined. Ten fungi were grown in a liquid medium supplemented with glucose as the repressor (0, 1%, 3%, and 5%), and the endo-xylanase and β-xylosidase productions were assayed. Aspergillus aculeatus FIG1 and A. oryzae KKB4 produced 3.85 and 0.70 U/mL of endo-xylanase, respectively, compared with other strains (0.22 U/mL or less). Trichoderma asperellum PK1J2, T. virens MLT2J2, A. aculeatus FIG1, T. asperellum MLT5J1, A. oryzae KKB4, and T. asperellum MLT3J2 produced 0.021–0.065 U/mL of β-xylosidase, whereas the other strains produced 0.013 U/mL or less of β-xylosidase. Adding 1% glucose to the growth medium can partially repress endo-xylanase production in A. aculeatus FIG1, T. asperellum PK1J2, and T. virens MLT4J1 and completely repress other strains. By adding 1% glucose, strains FIG1, PK1J2, and MLT4J1 suffered almost complete repression of β-xylosidase production, although such strains exhibited partial repression of endo-xylanase production. β-Xylosidase produced by the other strains showed complete repression by adding 1% glucose, except for A. aculeatus FIG1, A. tamarii FNCC 6151, and T. asperellum MLT1J1, which showed partial repression. Therefore, adding 3% glucose to the growth medium can result in complete repression of endo-xylanase and β-xylosidase productions in all strains examined.

The effect of water content and carbon source addition on lipase production from Aspergillus aculeatus Ms.11 using spent coffee ground

Lipase is one of the industrially important enzymes, however, the production needs costly substrate. To overcome the problem, we developed an effective medium formulation to produce lipase from indigenous lipolytic mould Aspergillus aculeatus Ms.11 using spent coffee ground. We observed the effect of additional glucose and olive oil, and the influence of water content on lipase production. The experiments were done using the Solid-State Fermentation (SSF) method for 7 days. The results show that optimum lipase production on substrates with additional glucose and olive oil observed on day 4 with lipase activity of 16.296 U/mL and lipase productivity of 150.32 U/g/day. The optimum water content from the results is 50%. The highest lipase activity obtained using the water content is 291.80 U/mL, while the highest lipase productivity is 106.32 U/g/day. The results showed that water content as well as the addition of glucose and olive oil, affects lipase productivity of Aspergillus aculeatus Ms.11 on spent coffee ground. Further studies to optimise the production condition are suggested.

Heterologous Biosynthesis and Genomics-Driven Derivatization of Fungal Bioactive Sesterterpenoid Variecolin

The biosynthetic gene cluster of fungal bioactive sesterterpenoids, variecolin (1) and variecolactone (2), was identified in Aspergillus aculeatus ATCC 16872. Heterologous production of 1 and 2 was achieved in Aspergillus oryzae by expressing the sesterterpene synthase VrcA and the cytochrome P450 VrcB. Intriguingly, the replacement of VrcB with homologous P450s from other fungal terpenoid pathways yielded three new variecolin analogues, one of which exhibited potent anticancer activity comparable to that of 1.

Primer estudio de dos especies de Aspergillus aisladas de bosques de manglar en Ecuador

Mangroves forests are located in tropical and subtropical regions, its adaptation and distribution in coastal regions is influenced by temperature, humidity, tidal and saline fluctuations. Therefore, there are exposed to multiple environmental fluctuations. Mangroves are inhabited by wildlife but also is supported by a diverse community of microorganisms, including fungi. Several fungi in mangroves have multiple ecological roles as saprotrophs or as an opportunistic pathogen, many of them are also used in the industry, as the genus Aspergillus, that are important in the biomedicine, industrial and environmental applications. In this study we isolated species of fungi from mangrove stems and propagules. They were identified by both morphological and by its molecular characteristics. Here, we report the first isolated of Aspergillus niger and Aspergillus aculeatus from mangrove in Ecuador. Research such as these highlights the importance to determine the role of fungi in mangrove ecosystem.

Production of amylases by some aspergillus and fusarium species isolated from waste corncobs in Keffi, Nigeria

Amylases are important industrial enzymes that have wide applications ranging from conversion of starch to sugar syrups, to the production of cyclodextrins for the pharmaceutical industry. This investigation aimed at production of amylases using Aspergillus and Fusarium species isolated from waste-corncobs in Keffi Nigeria. Standard microbiological methods were employed for isolation and identification of the fungal isolates. The yields of amylases produced by fungi isolates were determined using Spectrometry. The isolation rate of Aspergillus and Fusarium species was high in location A, C and D with 60% and location B with 40%. The percentage occurrence of the isolates demonstrated that Aspergillus carneus was 40%, Aspergillus aculeatus was 60% and Aspergillus flavus was 20% while Fusarium moniliforme was 80% and Fusarium redolens was 40%. The result demonstrated that three species of the fungal isolates Aspergillus aculeatus, Aspergillus carneus and Fusarium moniliforme were found to produce amylases. Aspergillus aculeatus isolated from locations C3, D1 and D2 produced 0.018mg/ml, 0.018mg/ml and 0.016mg/ml amylases respectively. Similarly, Aspergillus carneus isolated from locations A1 and B2 produced 0.021mg/ml and 0.012mg/ml amylases. Fusarium moniliforme isolated from locations A3, C1 and C4 produced 0.010mg/ml, 0.016mg/ml and 0.015mg/ml amylases. Result of effect of (temperature, pH and fermentation time) for production of amylases. Whereas highest amount for amylases produced by Aspergillus aculeatus and F monliforme were produced at 28 OC. pH 5.0 was found to the best optima pH for production of amylases from the fungi studied A. carneus (2.99 mg/ml amylases). The fermentation time showed highest production of amylase by A. carneus and A. aculeatus after 72 hours while F. moniliforme produced at 96hours. The fungi species isolated from soil in keffi can be used for production of amylases.

Citrus Segment Degradation Potential, Enzyme Safety Evaluation, and Whole Genome Sequence of Aspergillus aculeatus Strain ZC-1005

Aspergillus aculeatus ZC-1005 (ZC-1005 was used as the abbreviation of this strain) is a hemicellulase-producing strain isolated from rotten citrus rind buried in the soil. Our previous study has shown its biochemical properties including high xylanase activity, mannanase activity, and degradation reaction with citrus mesocarp. In this study, we focused more on the enzyme safety evaluation and the genome sequencing via PacBio and Illumina platforms. High biological safety of the crude enzymes of ZC-1005 has been proven by the acute oral toxicity test, sub-chronic toxicity test, micronucleus test, and sperm malformation test. The genome of ZC-1005 had a GC content of 52.53%, with a size of 35,458,484 bp, and encoded 10,147 genes. Strain ZC-1005 harbored 269 glycosyl hydrolase (GH) genes of 64 families. The fungus produces cellulose-acting (GH3, GH5, GH12, and GH1) and hemicellulose-acting enzymes (GH16, GH31, GH2, and GH92). In genome annotation, we paid more attention to the genes encoding xylanase, such as gene 01512, gene 05833, gene 05469, gene 07781, gene 08432, gene 09042, gene 08008, and gene 09694. The collaboration between complete genome information and the degradation test confirmed that ZC-1005 could degrade cellulose and xylan. Our results showed that the citrus enzymatic decapsulation technology was efficacious and safe for canned citrus product processing, which may also solve the industrial waste problem. Therefore, ZC-1005 and the crude enzyme secreted from the strain were very promising to be used in the citrus processing industry.

Serine–Arginine Protein Kinase-like Protein, SrpkF, Stimulates Both Cellobiose-responsive and D-Xylose-Responsive Signaling Pathways in Aspergillus Aculeatus

To elucidate the regulatory mechanisms of various cellulolytic enzyme genes in Aspergillus aculeatus , we identified one mutant that reduced the expression of FIII-avicelase ( chbI ) in response to cellulose from 12,000 A . aculeatus T-DNA-inserted mutants. The T-DNA inserted into a putative protein kinase gene similar to AN10082 in A . nidulans , the serine–arginine protein kinase F, SrpkF. The fold increase in srpkF gene expression in response to various carbon sources was 2.3 (D-xylose), 44 (Avicel®), 59 (Bacto™ Tryptone), and 98 (no carbon) compared with D-glucose. The deletion of srpkF in A . aculeatus resulted in a significant reduction in the cellulose-responsive expression of chbI , hydrocellulase ( cel7b ), and FIb-xylanase ( xynIb ) genes at an early induction phase. However, the srpkF deletion did not affect the expression of xynIb in response to D-xylose. Furthermore, the srpkF -overexpressing strain that expresses the srpkF gene at levels from four- to nine-fold higher than the control strain stimulated the expression of cbhI and cel7b in response to cellobiose and the FI-carboxymethyl cellulase gene ( cmc1 ) and xynIb in response to xylose. The expression of cbhI and cel7b is regulated by a transcriptional activator, ManR, and the expression of cmc1 and xynIb is regulated by XlnR. Our data demonstrate that SrpkF can stimulate both the ManR- and XlnR-dependent signaling pathways in response to cellobiose and D-xylose in A . aculeatus .