• Journal of Microbiology and Biotechnology
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• 제1권3호
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• pp.212-219
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• 1991

Four species of yeast, Saccharomyces cerevisiae, Candida utilis, Saccharomycopsis flbuligera, and Schwanniomyces castellii were evaluated for their ability to bioconvert potato processing waste water into microbial protein and the resulting single-cell proteins were evaluated as protein sources for rainbow trout, using in vitro analyses. The studies indicated that Schwanniomyces castellii, which utilizes starch dircetly and converts it into cell mass efficiently, was suitable for the bioconversion. In the single-stage continuous bioconversion, the yield S. castellii cell mass, which contained approximately 37% protein, was 77%, at dilution rate 0.25 $h^{-1}$. Reduction of total carbohydrate was 81%. During batch fermentations, cell mass yield was about 72% and total carbohydrate reduction was 81%. Among the yeasts tested, S. castellii possessed the most fragile cell wall and had a favorable amino acid profile for salmonid fish; protein score of 86% (Met). In an in vitro pepsin digestibility test 80% digestibility (23~38% above control) was observed when cells were pre-heated in a steam bath for 30 min. Results presented should be regarded as being preliminary in nature because they were derived from single experiments.

• Journal of Microbiology and Biotechnology
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• 제20권9호
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• pp.1300-1306
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• 2010

Ethyl (R, S)-4-chloro-3-hydroxybutanoate (ECHB) is a useful chiral building block for the synthesis of L-carnitine and hypercholesterolemia drugs. The yeast reductase, YOL151W (GenBank locus tag), exhibits an enantioselective reduction activity, converting ethyl-4-chlorooxobutanoate (ECOB) exclusively into (R)-ECHB. YOL151W was generated in Escherichia coli cells and purified via Ni-NTA and desalting column chromatography. It evidenced an optimum temperature of $45^{\circ}C$ and an optimum pH of 6.5-7.5. Bacillus subtilis glucose dehydrogenase (GDH) was also expressed in Escherichia coli, and was used for the recycling of NADPH, required for the reduction reaction. Thereafter, Escherichia coli cells co-expressing YOL151W and GDH were constructed. After permeablization treatment, the Escherichia coli whole cells were utilized for ECHB synthesis. Through the use of this system, the 30 mM ECOB substrate could be converted to (R)-ECHB.

• Mycobiology
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• 제33권3호
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• pp.150-157
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• 2005

The fungal flora decomposing rice straw were investigated all over the soil of Sharkia Province, east of Nile Delta, Egypt, using the nylon net bag technique. Sixty-four straw-decomposing species belonging to 30 genera were isolated by the dilution plate method in ground rice straw-Czapek's agar medium at pH 6. The plates were incubated separately at $5^{\circ}C,\;25^{\circ}C\;and\;45^{\circ}C$, respectively. Twenty nine species belonging to 14 genera were isolated at $5^{\circ}C$. The most frequent genus was Penicillium (seven species), and the next frequent genera were Acremonium (three species), Fusarium (three species), Alternaria, Chaetomium, Cladosporium, Mucor, Stachybotrys (two species) and Rhizopus stolonifer. At $25^{\circ}C$, 47 species belonging to 24 genera were isolated. The most frequent genus was Aspergillus (nine species), and the next frequent genera were ranked by Penicillium (five species), Chaetomium (three species), Fusarium (three species). Each of Alternaria, Cladosporium, Mucor, Myrothecium and Trichoderma was represented by two species. At $45^{\circ}C$, 15 species belonging to seven genera were isolated. These were seven species of Aspergillus, two species of Chaetomium and two species of Emericella, while Humicola, Malbranchea, Rhizomucor and Talaromyces were represented by one species respectively. The total counts of fungi the genera, and species per gram of dry straw were significantly affected by incubation temperature and soil analysis (P < 0.05).

• KSBB Journal
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• 제7권3호
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• pp.161-165
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• 1992

Microemulsions에 교차결합(crosslinking)고정화한 Microemulsions sp(NRRL B-3683)를 이용하여 소수성기질인 sitosterol로부터 AD, ADD를 합성하였다. Mycobacteria bioconversion활성도는 계면활성제의 종류와 물의 양에 의존한다. Mycobacteria는 양이온 microemulsions(CTAC-buthanol-cyclohexa-ne-water)에서 가장 높은 활성도를 갖으며, 이것은 buffer에서보다 5배 이상 효율을 갖음을 나타낸다. 음이온 microemulsions에서는 활성도가 매우 낮다. 양이온 microemulsions에서활성도는 물의 양에 따라서 변하며 물의 양이 증가함에 따라서 증가한다. 20%의 물을 포함한 microemulsions에서는 5%의 물을 포함한 microemulsions에서보다 약 배의 효율을 갖는다. 이와같이 microemulsions은 미생물을 이용한 bioconversion반응의 매질로써 효과적일 수 있다.

• Mycobiology
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• 제33권2호
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• pp.90-96
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• 2005

Sixty two out of the sixty four species of fungal isolates tested could produce both $exo-{\beta}1,4-gluconase\;(C_1)$ and $endo-{\beta}1,4-gluconase\;(C_x)$ on pure cellulose and rice straw as carbon source in Czapek's medium. Fifty-eight and fifteen species were able to grow at $25^{\circ}C$ and at $45^{\circ}C$, respectively. Eleven species could grow at both $25^{\circ}C$ and $45^{\circ}C$ while, four species appeared only at $45^{\circ}C$. The most cellulolytic species at $25^{\circ}C$ was Trichoderma koningii producing 1.164 $C_1$ (mg glucose/1 ml culture filtrate/1 hr) and 2.690 $C_x$ on pure cellulose, and 0.889 $C_1$, and 1.810 $C_x$ on rice straw, respectively. At $45^{\circ}C$, the most active thermotolerant species were Aspergillus terreus, followed by A. fumigatus. Talaromyces thermophilus was the highest active thermophilic species followed by Malbranchea sulfurea. Most of these species were also active in fermentation of rice straw at 25 and $45^{\circ}C$ (P<0.05). The most active ones were T. koningii, A. ochraceus and A. terreus, which produced 201.5, 193.1 and 188.1 mg crude protein/g dry straw, respectively.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.295-298
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• 2006

Actinomycetes are ubiquitous Gram-positive soil bacteria and a group of the most important industrial microorganisms for the biosynthesis of many valuable secondary metabolites as well as the source of various bioconversion enzymes. Cytochrome P450 hydroxylase (CYP), a hemebinding protein, is known to be involved in the modification of various natural compounds, including polyketides, fatty acids, steroids, and some aromatic compounds. Previously, six different novel CYP genes were isolated from a rare actinomycetes called Sebekia benihana, and they were completely sequenced, revealing significant amino acid similarities to previously known CYP genes involved in Streptomyces secondary metabolism. In the present study, these six CYP genes were functionally expressed in Streptomyces lividans, using an $ermE^{*}$ promoter-containing Streptomyces expression vector. Among six CYP genes, two S. benihana CYP genes (CYP503 and CYP504) showed strong hydroxylation activities toward 7-ethoxycoumarin. Furthermore, the recombinant S. lividans containing both the S. benihana CYP506-ferredoxin genes as well as the S. coelicolor feredoxin reductase gene also demonstrated cyclosporin A hydroxylation activity, suggesting potential application of actinomycetes CYPs for the biocatalysts of natural product bioconversion.

• Natural Product Sciences
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• 제20권2호
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• pp.102-106
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• 2014

Gumiganghwal-tang (GMT) is a traditional herbal prescription used for treatment of the common cold, pain, and inflammatory diseases. Variations in the amounts of bioactive components of GMT and GMT fermented with 10 Lactobacillus strains were investigated by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Simultaneous qualitative and quantitative analyses of eleven bioactive compounds (prim-O-glucosylcimifugin, liquiritin, cimifugin, baicalin, liquiritigenin, wogonoside, baicalein, wogonin, butylphthalide, imperatorin, and isoimperatorin) were performed, with comparison of their retention times (tR) and UV spectra with those of standard compounds. The amounts of baicalin (8.71 mg/g), liquiritigenin (5.28 mg/g) and butylphthalide (5.10 mg/g) were the major compounds in GMT. We found that L. fermentum KFRI 145 fermented wogonoside and baicalin to their aglycones, wogonin and baicalein, respectively. These results indicated that L. fermentum KFRI 145 has potential as a functional starter culture for manufacturing fermented GMT.

• Mycobiology
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• 제34권1호
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• pp.14-21
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• 2006

Crude protein (CP) content of mechanically ground rice straw into small particles by an electric grinder and reducing value (RV) and soluble protein (SP) in the culture filtrate were lower than that of the chopped straw into $5{\sim}6\;cm$ lengths when both ground and chopped straws were fermented with Aspergillus ochraceus, A. terreus or Trichoderma koningii, at steady conditions. The reduction rate of RV, SP and CP was 22.2, 2.4, 7.3%; 9.1, 4.9, 8.5% or 0.0, 0.0, 3.6% for the three fungi, respectively. Chemical pretreatment of straw by soaking in $NH_{4}OH$ for a day caused significant increase in CP of the fermented straw than the other alkali and acidic pretreatments. Gamma irradiation pretreatment of dry and wet straw with water, specially at higher doses, 100, 200 or 500 kGy, caused significant increase in RV and SP as CP in the fermented straw by any of these fungi. Chemical-physical combination pretreatment of rice straw reduced the applied dose of gamma irradiation required for increasing fermentable ability of fungi from 500 kGy to 10 kGy with approximately the same results. Significant increases in RV and SP of fermented straw generally occurred as the dose of gamma irradiation for pretreated straw, which combined with $NH_{4}OH$, gradually rose. Whereas, the increase percentage in CP of fermented straw that was pretreated by $NH_{4}OH-10\;kGy$ was 12.4%, 15.4% or 8.6% for A. ochraceus, A. terreus or T. koningii, respectively.

• Journal of the Korean Wood Science and Technology
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• 제37권3호
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• pp.274-286
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• 2009

목질바이오매스 원료는 구성성분 특성 및 분포상 생물 화학적 전환에 매우 큰 장애요소를 지니고 있다. 특히 셀룰로우스를 이용하고자 하는 경우의 리그닌 장애는 해결해야 할 중요한 요소로 인식되고 있어 바이오에탄올 생산에서도 당화공정에 앞서 전처리 공정이 필연적이며 최종 에탄올 수율 및 생산비용에도 영향이 커서 다양한 전처리 방법들이 제안되고 있는 상황이다. 본 총설은 문헌연구를 통하여 최근 세계적으로 진행되고 있는 목질바이오매스 대상의 전처리 연구에 대한 동향을 파악하고, 이들 전처리공정의 특징 및 장단점을 분석하여 국내 목질바이오매스 원료 및 생산여건에 적합한 공정 연구 개발에 필요한 기초자료를 마련하고자 하였다. 국내외적으로 활발하게 연구되는 주요 전처리 기술은 각각 공정 및 경제성 면에서 장단점이 있어 원료나 생산여건 환경에 따라 적합한 전처리 공정을 선택해야 할 필요가 있는 것으로 고찰되었다.

• 한국미생물·생명공학회지
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• 제11권3호
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• pp.193-199
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• 1983

보리짚이나 옥수수 속과 같은 농산폐자원으로부터 xylose를 생산하기 위한 생물전환공정에 관한 연구를 수행했다. 보리짚이나 1% 가성소다용액으로 24시간 3$0^{\circ}C$ 전처리한후 3$0^{\circ}C$에서 48시간 효소 가수분해를 시킨 결과 15.8%의 환원당을 유리시켰다. 이 환원당의 량은 보리 짚에 들어있는 전 D-xylose 함량에 87%에 해당하는 것이다. 여러 가지 농산폐자원의 효소전환공정을 시험한 결과, 보리짚과 옥수수속이 D-xylose 생산에 가장 적합한 원료가 픽수 있음을 관찰하였다.