Research Support, Non-U.S. Gov't
- Biological Pretreatment of Softwood Pinus densiflora by Three White Rot Fungi
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Jae-Won Lee , Ki-Seob Gwak , Jun-Yeong Park , Don-Ha Choi , Mi Kwon , In-Gyu Choi
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J. Microbiol. 2007;45(6):485-491.
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DOI: https://doi.org/2647 [pii]
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Abstract
- The effects of biological pretreatment on the Japanese red pine Pinus densiflora, was evaluated after exposure to three white rot fungi Ceriporia lacerata, Stereum hirsutum, and Polyporus brumalis. Change in chemical composition, structural modification, and their susceptibility to enzymatic saccharification in the degraded wood were analyzed. Of the three white rot fungi tested, S. hirsutum selectively degraded the lignin of this sortwood rather than the holocellulose component. After eight weeks of pretreatment with S. hirsutum, total weight loss was 10.7%, while lignin loss was the highest at 14.52% among the tested samples. However, holocellulose loss was lower at 7.81% compared to those of C. lacerata and P. brumalis. Extracelluar enzymes from S. hirsutum showed higher activity of ligninase and lower activity of cellulase than those from other white rot fungi. Thus, total weight loss and changes in chemical composition of the Japanese red pine was well correlated with the enzyme activities related with lignin- and cellulose degradation in these fungi. Based on the data obtained from analysis of physical characterization of degraded wood by X-ray Diffractometry (XRD) and pore size distribution, S. hirsutum was considered as an effective potential fungus for biological pretreatment. In particular, the increase of available pore size of over 120 nm in pretreated wood powder with S. hirsutum made enzymes accessible for further enzymatic saccharification. When Japanese red pine chips treated with S. hirsutum were enzymatically saccharified using commercial enzymes (Cellulclast 1.5 L and Novozyme 188), sugar yield was greatly increased (21.01%) compared to non-pretreated control samples, indicating that white rot fungus S. hirsutum provides an effective process in increasing sugar yield from woody biomass.
- An Improved Selective Isolation of Rare Actinomycetes from Forest Soil
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Chi Nam Seong , Ji Heok Choi , Keun-Shik Baik
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J. Microbiol. 2001;39(1):17-23.
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Abstract
- Various pretreatment procedures and selective media were applied to assess the optimal conditions for the isolation of rare actinomycetes from soil. Pretreatment of wet-heating for 15 min at 70oC and phenol treatment of soil suspension were the most effective methods for the isolation of those microorganisms. Hair hydrolysate vitamin agar (HHVA) was the most suitable medium for the recovery of rare actinomycetes. Thirty-five rare actinomycete strains were chosen using selective isolation approaches, then morphological and chemical properties of the isolates were determined. The isolates belonged to one of the following genus, Micromonospora, Microbispora, Actinoplanes and Streptosporangium.