MSK
Search
- Page Path
- HOME > Search
Research Support, Non-U.S. Gov'ts
- Diversity of Thermophilic Fungi in Tengchong Rehai National Park Revealed by ITS Nucleotide Sequence Analyses
- Wen-Zheng Pan , Xiao-Wei Huang , Kang-Bi Wei , Chun-Mei Zhang , Dong-Mei Yang , Jun-Mei Ding , Ke-Qin Zhang
- J. Microbiol. 2010;48(2):146-152. Published online May 1, 2010
- DOI: https://doi.org/10.1007/s12275-010-9157-2
- 34 View
- 0 Download
- 36 Scopus
-
Abstract
- The geothermal sites near neutral and alkalescent thermal springs in Tengchong Rehai National Park were examined through cultivation-dependent approach to determine the diversity of thermophilic fungi in these environments. Here, we collected soils samples in this area, plated on agar media conducive for fungal growth, obtained pure cultures, and then employed the method of internal transcribed spacer (ITS) sequencing combined with morphological analysis for identification of thermophilic fungi to the species level. In total, 102 strains were isolated and identified as Rhizomucor miehei, Chaetomium sp., Talaromyces thermophilus, Talaromyces byssochlamydoides, Thermoascus aurantiacus Miehe var. levisporus, Thermomyces lanuginosus, Scytalidium thermophilum, Malbranchea flava, Myceliophthora sp. 1, Myceliophthora sp. 2, Myceliophthora sp. 3, and Coprinopsis sp. Two species, T. lanuginosus and S. thermophilum were the dominant species, representing 34.78% and 28.26% of the sample, respectively. Our results indicated a greater diversity of thermophilic fungi in neutral and alkaline geothermal sites than acidic sites around hot springs reported in previous studies. Most of our strains thrived at alkaline growth conditions.
- Purification and Biochemical Properties of a Glucose-Stimulated β-D-Glucosidase Produced by Humicola grisea var. thermoidea Grown on Sugarcane Bagasse
- Cesar Vanderlei Nascimento , Flávio Henrique Moreira Souza , Douglas Chodi Masui , Francisco Assis Leone , Rosane Marina Peralta , João Atílio Jorge , Rosa Prazeres Melo Furriel
- J. Microbiol. 2010;48(1):53-62. Published online March 11, 2010
- DOI: https://doi.org/10.1007/s12275-009-0159-x
- 37 View
- 0 Download
- 57 Scopus
-
Abstract
- The effect of several carbon sources on the production of mycelial-bound β-glucosidase by Humicola grisea var. thermoidea in submerged fermentation was investigated. Maximum production occurred when cellulose was present in the culture medium, but higher specific activities were achieved with cellobiose or sugarcane bagasse. Xylose or glucose (1%) in the reaction medium stimulated β-glucosidase activity by about 2-fold in crude extracts from mycelia grown in sugarcane bagasse. The enzyme was purified by ammonium sulfate precipitation, followed by Sephadex G-200 and DEAE-cellulose chromatography, showing a single band in PAGE and SDS-PAGE. The β-glucosidase had a carbohydrate content of 43% and showed apparent molecular masses of 57 and 60 kDa, as estimated by SDS-PAGE and gel filtration, respectively. The optimal pH and temperature were 6.0 and 50°C, respectively. The purified enzyme was thermostable up to 60 min in water at 55°C and showed half-lives of 7 and 14 min when incubated in the absence or presence of 50 mM glucose, respectively, at 60°C. The enzyme hydrolyzed p-nitrophenyl-β-D-glucopyranoside, p-nitrophenyl-β-galactopyranoside, p-nitrophenyl-β-D-fucopyranoside, p-nitrophenyl-β-D-xylopyranoside, o-nitrophenyl-β-Dgalactopyranoside, lactose, and cellobiose. The best synthetic and natural substrates were p-nitrophenyl-β-Dfucopyranoside and cellobiose, respectively. Purified enzyme activity was stimulated up to 2-fold by glucose or xylose at concentrations from 25 to 200 mM. The addition of purified or crude β-glucosidase to a reaction medium containing Trichoderma reesei cellulases increased the saccharification of sugarcane bagasse by about 50%. These findings suggest that H. grisea var. thermoidea β-glucosidase has a potential for biotechnological applications in the bioconversion of lignocellulosic materials.
First
Prev
TOP
