• Microbiology and Biotechnology Letters
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• v.2 no.1
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• pp.1-7
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• 1974

For the purpose of producing cellulosic single-cell protein from the agricultural wastes, 172 strains of cellulose-assimilating bacteria were isolated from 102 samples of rotten woods, compost soils, soils and so on by the enrichment culture technique. The isolates were examined for their ability to utilize cellulose as carbon source, and then six strains were screened by their strong cellulose assimilating ability and identified as follows: 1. Among six strains of bacteria screened, five strains were identified as species belonged to the genus Cellulomonas and the remainder to the genus of Sporocytophaga. 2. The isolated Sporocytophaga species was identified as S. ellipsosporn because it has a ellipsoidal microcyst. 3. The isolated Cellulomonas species were identical to a strain of C. fimi, C. aurcgena, C. gelida, respectively and two strains to C. flavigena. 4. The isolated C. aurogena was proved to be a new variety becauuse it has different characteristics of assimilating pentoses such as arabinose and xylose from the strain discribed in Bergey's Manual.

• Microbiology and Biotechnology Letters
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• v.4 no.3
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• pp.105-110
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• 1976

In the studies of microbiological utilization of cellulosic wastes, cellulolytic fungi were isolated and screened out. At the first stage, 221 cellulolytic fungi were isolated from different sources such as soils, humus, composts and rotten wood debris by enrichment culture techniques. In the second stage, 36 strains of fungi out of those previously isolated were selected for their cellulase activities estimated by means of filter paper degradation, carboxy methyl cellulose liquefaction and cup method. Activities of C$_1$-cellulase, C$\sub$x/-cellulase and filter paper activity were adopted on the final screening stage and five different strains which are tentatively identified as Aspergillus sp.(strain No. AS-9), Penicillium sp. (strain No. KNI-1-2), Trichoderma, sp. (strain No. KI-7-2, KI-7-5, KI-4-1-1B) were selected for their high potency of C$_1$ and C$\sub$x/-cellulase activities. When rice straw milled and treated with NH$_4$OH was hydrolyzed with the crude enzyme Prepared from the culture broth of Trichoderma sp. (strain No. KI-4-1-1B), saccharification rate was obtained up to 26％.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.04a
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• pp.113.1-113
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• 1979

Each year, vast amount of agricultural crop residues are produced (about 60 percent of the total crop production), which have not been effectively utilized because they are bulky and lignocellulosic, thus having little fuel energy per unit volume. Using treated plant residues as animal feeds could result in an ultimate saving of fossil fuel energy and a more effective utilizat ion of products created by the photosynthetic process. Feeding the residues to animals would decrease the pollution potential, but these residues are difficult for even a ruminant animal to digest. If cellulosic wastes produced from cereal grain straw and wood could be digested, land now used for producing forage add grain cnuld be shifted to food crops for humans. During the past decade, considerable efforts were made to utilize crop residues. These utilization methods can be broadly grouped into for categories: (1) direct uses, (2) mechanical conversions, (3) chemical conversions and (4) biological conversions. Agricultural crop residues consist mainly of cellulose, hemicellulose, lignin, pectin, andother plant carbohydrates. The nature of the constituents of these residues can be best utilized as one of the five FS: Fuel, Fiber, Fertilizer, Feed and Food. Many processes have teen proposed and some are in industrial production stage. However, economics of the process depend on the location where availability of other competitive products are different.

• Microbiology and Biotechnology Letters
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• v.7 no.2
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• pp.91-95
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• 1979

Ethanol and Xylose were produced from cellulosic agricultural waste such as rice straw and corn cob by a single-step simultaneous hydrolysis-fermentation process utilizing semi-solid culture of Trithoderma as enzyme source and Saccharomyces yeast. By this process all the hexoses prduoced by the enzyme were converted to ethanol leaving pentoses which are not fermented by the yeast. By processing 50 g of rice straw, 18 ml of ethanol and 2.7 g of xylose were produced and 50 g corn cob produced 3.8 ml of ethanol and 10.8 g of xylose. Alkali-treatment of rice straw showed little effects on the productivities of ethanol and xylose. The possible reasons are discussed.

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.1-8
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• 1978

In order to develop the processes for the production of fermented feed from cellulosic agricultural by-product, cereal straw, by th action of cellulolytic fungus, the properties of the cellulolytic enzyme produced by Trichoderma sp. KI 7-2 was studied. A higher enzyme activity was obtained in the culture added by 1％ rice or barley straw powder than in the culture of pure cellulose. The crude enzyme was prepared by precipitating from 20∼60％ saturated ammonium sulphate of the culture supernatant. The optimum conditions for the enzyme reaction were temperature of of 50$^{\circ}C$ and pH 4.2. The crude enzyme was static at 50$^{\circ}C$ for two hours and at pH between 4 and 6. These properties were adopted for the fermented feed production, and several production. Thus, several processes of semisolid culture were devicced to up grade tile fermented feed and to develop into the acceptable quality.

• Microbiology and Biotechnology Letters
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• v.6 no.2
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• pp.51-57
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• 1978

The study was made of the cultural condition and physiological characteristics of the symbiotic pair of microorganisms, Cellulomonas flavigena and the second organism. It also contains the results of a taxonomical study of the second organism. The results obtained wers summarized as follows : 1) Cell yield of the mixed culture, Cellulomonas and the second organism, was higher than that of each pure culture in CM-Cellulose medium. 2) The taxonomical characteristics of the second organism revealed that it probably belonged to the genus Sporocytophaga because it had a gliding motility and microcyst. 3) Optimum pH of the mixed culture was found to be in the vicinity of 7.2, and optimum temperature of the cell growth in the mixed culture was observed to be in the vicinity of 30$^{\circ}C$. 4) It was found that the majority of the population during growth in the mixed culture consisted of Cellulomonas flavigena. 5) Cellulomonas flavigena required thiamine and biotin as growth factors but Sporocytophaga sp. had no requirement of vitamins. 6) Gulucose was not found in detectable amounts in the medium of Cellulomonas flavigena but it was traced in the mixture by thin layer chromatography. 7) Sixteen amino acids were analyzed from the cell protein of Cellulomonas flavigena by amino acid autoanalyzer. The amount of the leucine, valine and arginine was very high.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.65-69
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• 1981

As a process to utilize agricultural residues, simultaneous hydrolysis-fermentation (SSF) was compared with fermentation of enzymic hydrolyzate using koji cultures of Trichoderma sp. KI 7-2 and a thermotolerant yeast Saccharomyces cerevisiae NCYC 716. Cellobiose was not detected in SSF broth whilst 15 mg/$m\ell$ of the disaccharide was found in enzymic hydrolysate of rice straw using the same enzyme source. It was found that converting glucose to ethanol in SSF process reactivated the cellobiase activity, which is inhibited by the accumulation of glucose in enzymic hydrolysis process. Cutting milled rice straw was fermented as effectively as ball milled one in SSF process. From tile results discussions are made on the product inhibition mechanism of cllulolytic enzyme system.

• Microbiology and Biotechnology Letters
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• v.5 no.3
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• pp.127-131
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• 1977

Various kinds of native herbage grasses like-Miscanthus sinensis, Arundinella hirta, Cymbopogen geirngii, Themeda japonica etc. are widely distributed in every Korean mountain. So we investigated the availability of native grass, Miscanthus sinensis as a substrate for the production of S. C. P. The results were obtained as follows. 1) At the alkali treatment, NaOH was the most effective with the exclusion of lignin, and pretreated Miscanthus with NaOH appeared to be a good substrate for the microbial growth. 2) When Miscanthus was treated with one to 10％ NaOH, the microbial growth increased in proportion to the increased alkali concentration. Beyond 4％ NaOH, a slight increase was observed. 3) Phosphoric acid, as a neutralizer, was the most effective in cell production after alkali treatment. 4) On the effect of incubation time, the productivity was best found at 60 hours, and the cell weight was 9.23 mg per 1 ml, and the microbial digestibility of substrate was 75.2％.

• Microbiology and Biotechnology Letters
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• v.4 no.3
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• pp.99-104
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• 1976

Experiments were carried out to establish the effects of acids in neutralization after alkaline treatment of rice straw, with which cellulosic single cell protein can be produced by cellulose utilizing bacteria, Cellulomonas flavigena KIST 321, previously isolated by authors. Following results were obtained. 1. Rice straw as carbon source was pretreated with 10 volumes of 1 normality of NH$_4$OH or NaOH(NaOH/substrate：40％, and then washed with water or neutralized with H$_3$PO$_4$, H$_2$SO$_4$, HCl and CH$_3$COOH. Among the above mentioned methods, neutralization with H$_3$PO$_4$after alkaline treatment was proved to be the most effective on its digestibility and SCP production. Dry cell 12.28g/$\ell$ and 78％ digestibility were obtained. 2. When rice straw was treated with NaOH solution, the result suggested that the productibity of cell-mass was attained on treatment of rice straw with 6％ of NaOH (NaOH/substrate ratio) for 15～24hrs at room temperature. 3. When rice straw was treated with NaOH, a volume of water to substrate is adequate by two or three fold and the amount of NaOH can be economized up to 5％ for the weight of rice straw. 4. The steaming of rice straw at 121$^{\circ}C$ for 30min. in alkaline treatment of rice straw gave the similiar effectiveness to that at room temperature for 15～24hrs. and accelerated the sterilization of the substrate. 5. Finally, the level of inorganic phosphate in a medium was investigated. 11.2g of dry cell was produced at the concentration of 0.2％, phosphate (phosphorous level 0.04％) in medium even though treated rice straw was neutralized with HCI instead of H$_3$PO$_4$, and 12.2g/$\ell$ at the concentration of 0.3％ phosphate (phosphorous 0.04％) on neutralization with H$_2$SO$_4$.

• Journal of the Korean Wood Science and Technology
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• v.12 no.3
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• pp.25-34
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• 1984

This experiment was carried out to investigate the effects of monosaccharides extracted by saturated portland cement solution on the cement setting in comparision with the inhibitory index (I) of each lignocellulosic-cement system. The wood species which have been widely reforested in Korea, Populus alba-grandulosa, Larix leptolepis, Abies holophylla, Pinus koraiensis, Pinus rigida, Pinus densiflora and agricultural wastes of rice husk and rice stalk were used at this study. The wood meal, 0.50g on dry weight basis, through 0.83 mm(20 mesh) and retained on 0.35mm (40 mesh) screen was extracted by 25 ml saturated portland cement solution and the pH of saturated portland cement solution Was 12.7. To eliminate cation exsisting in the extracted solution, the cation exchange column was used (Fig. 4). Afterwards the extracted monosaccharides were reduced into alditols with sodium borohydride and analyzed by the gas-liquid chromatography for xylan, mannan, arabinan, galactan, gluean. The heat of cement hydration for lignocellulosic-cement system was measured in Dewar flask (Fig. 2). And then the inhibitory indices were calculated from maximum hydration temperature, time and maximum slops of hydration curve of ligno cellulosic-cement systems. The results obtained were as follows; (1) The inhibitory index of pines-Pinus rigida (I=29.33) and Pinus densiflora (I=35.76), were lower than that of poplar-Populus alba-glandulosa (I=41.48), and the index of Larix ieptoiepis (I=73.00) was the highest among eight lignocellulosic-cement systems, and accordingly both Pinus rigida and Pinus des(flora were seemed to be good wood species for wood-cement composite manufacture. (2) In case of Pinus rigida, the inhibitory index was 29.33 and the ratio of the hexoses to the pemoses was 6.04 and in case of Larix leptolepis, the index and the ratio were 73.00 and 35.19, respectively. Therefore the inhibitory index increased with increasing the ratios of the hexoses to the pentoses. (3) The richer amount of xylose and mannose in species caused decreasing the slops of the hydration curve of the lignocellulosic-cement system, prohahly due to the chemical adsorption of the acetyl groups in the hemicellulose on the surface of cement grains. (4) The amoun of xylose and mannose were significant to the inhibitory index of each lignocellulosic-cement system but any specific relation between the amount of glucose and inhibitory index was not found.