ABSTRACT
The objective of the present work was to evaluate the water hyacinth (WH) as a substrate for the production of hydrolytic enzymes (cellulases and hemicellulases) of 100 strains of filamentous fungi under conditions of solid growth. Five fungal strains, identified as Trichoderma harzianum, Trichoderma atroviride, Penicillium griseofulvum, Penicillium commune and Aspergillus versicolor, were selected and studied for their ability to grow on water hyacinth as a substrate and carbon source only, evaluating hydrolytic enzymatic activities (α-l-arabinofuranosidase, cellulase, xylanase and ß-d-xylopyranosidase) and extracellular protein per g of water hyacinth dry matter (gdm). The five strains selected were able to produce the four enzymes studied; however, T. harzianum strain PBCA produces the highest xylanase (149.3 ± 14.3 IU/gdm at 108 h), cellulase (16.4 ± 0.6 IU/gdm at 84 h) and ß-d-xylopyranosidase (127.7 ± 14.8 IU/gdm at 48 h). In contrast, the fungus with the highest α-l-arabinofuranosidase activity was A. versicolor, with 129.8 ± 13.3 IU/gdm after 108 h. In conclusion, T. harzianum showed the best production of the hydrolytic enzymes studied, using as a matrix and carbon source, water hyacinth. In addition, catalytic activities of arabinofuranosidase and xylopyranosidase were reported for the first time in T. versicolor and T. harzianum.
ABSTRACT
Las levaduras juegan un importante rol en la naturaleza siendo el mayor reservorio de ellas el suelo. Mediante el método de las diluciones seriadas y posterior siembra en agar Sabouraud se aislaron en cultivo puro 77 cepas de levaduras desde un mismo suelo trumao del sur de Chile, usado como pradera permanente (30 cepas), pradera en rotación (30 cepas) y como control bosque nativo (17 cepas), estas cepas se identificaron molecularmente por PCR-RFLP en conjunto con secuenciación del rDNA de ITS-5.8S, además se realizo una caracterización fisiológica (asimilación fuente de carbono, de nitrógeno y fermentación de azucares) a cada cepa. Mediante las técnicas moleculares las 77 cepas se reunieron en 10 grupos, de estos solamente tres grupos se pudieron identificar a nivel de especie y uno hasta género: Devariomyces hansenii. Pichia fermentan. Kazachstania exigua., Candida sp.
Yeasts plays an important role in nature, It is the largest reservoir of soil them. By the method of serial dilutions and subsequent planting in Sabouraud agar were isolated in pure culture 77 strains of yeast from the same volcanic ash soil of southern Chile, used as permanent pasture (30 strains), rotation pasture (30 strains) and native forest as a control (17 strains), these strains were identified molecularly by PCR-RFLP in conjunction with rDNA sequencing ITS-5.8S, physiological characterization addition was performed to each strain (carbon and nitrogen source assimilation and fermentation of sugars). Using molecular techniques met the 77 strains in 10 groups; only three groups could be identified to species level and one to gender: Devariomyces hansenii; Pichia fermented; Kazachstania exigua; Candida sp.
Subject(s)
Humans , Genetic Markers , Yeasts/isolation & purification , Yeasts/physiology , Yeasts/genetics , Yeasts/metabolism , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Soil Microbiology , Chile , Volcanic Eruptions/adverse effects , Porosity , Soil CharacteristicsABSTRACT
In this work, the extracellular protease Eap1 from Sporisorium reilianum was characterized in solid and liquid cultures using different culture media. The results showed that Eap1 was produced in all media and under all culture conditions, with the most activity in solid culture at an acidic pH of 3-5. Following purification, the 41 kDa protease demonstrated aspartyl protease activity. The enzyme was stable at a wide range of temperatures and pH values, but 45°C and pH 3 were optimal. The K(m) and V(max( values obtained were 0.69 mg/mL and 0.66 µmol/min, respectively, with albumin as the substrate. Eap1 degraded hemoglobin as well as proteins obtained from corn germ, roots, stems and slides at pH 3 and also had milk-clotting activity. Sequencing analysis showed that this protein has 100% similarity to the peptide sequence theoretically obtained from the sr11394 gene, which encodes an aspartyl protease secreted by S. reilianum.
Subject(s)
Aspartic Acid Proteases/chemistry , Aspartic Acid Proteases/metabolism , Fungal Proteins/chemistry , Fungal Proteins/metabolism , Ustilaginales/enzymology , Albumins/metabolism , Amino Acid Sequence , Animals , Cattle , Culture Media/chemistry , Culture Media/metabolism , Extracellular Space , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Molecular Sequence Data , Sequence Alignment , Temperature , Ustilaginales/chemistryABSTRACT
Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research.
