To examine the potential utilization of chitosan, the biodegradable natural polymer, as a control agent of apple white rot caused by Botryosphaeria dothidea in a new control measure by coating it on the diseased branches, the various antifungal activities of chitosan was investigated. Chitosan showed significant inhibitory effect on the mycelial growth of B. dothidea, along with the morphological changes including hyphal swelling and ultrastructural changes on solid PDA medium. In liquid PD broth medium, the chitosan showed more significant effect on the growth of B. dothidea also forming cell clusters indicating affection on the hyphal extension. The growth of B. dothidea was inhibited more than 90% at the concentration of 1.0 mg/ml. Chitosan also detained the spore germination and induced the morphological change of germ tubes. Glucosamine, monomer of chitosan, did not affect on the growth of B. dothidea indicating the antifungal activity was caused by chitosan polymer.

An extremely cadmium tolerant yeast, Hansenula anomala B-7 used to determine the modification of the intracellular enzyme activities by cadmium ion. The activities of alcohol dehydrogenase, phosphofructokinase, and cytidine deaminase were decreased up to 90%, 40%, and 86% compa- red with the control by 1 mM cadmium nitrate respectively, but the activities of malate dehydrogenase, 6- phosphogluconate dehydrogenase, cytochrome c oxidase, and alkaline phosphatase were increased up to 440%, 136%, 260% and 155% compared with the control by 1 mM cadmium nitrate respectively. These results show that the activities of the enzymes participating in Embden-Mayerhof pathway (e.g. anaerobic metabolism) were reduced by cadmium, but those involved in hexose monophosphate pathway and tricarboxylic acid cycle (e.g. aerobic metabolism) were stimulated in contrast. It has been suggested that the diminished activity of cytidine deaminase in pyrimidine nucleotide dissimilation occured due to the inhibited nucleotide dissimilation by cadmium ion; the enhanced activity of cytochrome c oxidase was specifically required in order to oxidize a raised amount of NADH and NADPH due to the increased aerobic metabolism.

A bacterium producing Cyclodextrin Glucanotransferase (CGTase) and Cyclodextrinase (CDase) was isolated from soil, and named as Bacillus stearothermophilus KJ16. The growth of the isolated strain occurred in two steps, and syntheses of CGTase and CDase were dependedt on the growth cycle of the cell. CGTase was constitutively synthesized during the 1st growing phase, while CDase was synthesized inducibly during the 2nd growing phase. When the midium pH was controlled at 7.0 the maximum enzyme activities of CGTase and CDase were increased by 12-fold (1300 mU/ml) and 2-fold (225 mU/ml), respectively, compared with the pH-uncontrolled batch culture. The CGTase of the isolate converted soluble starch to CDs with the ratio of $\alpha$-CD:$\beta$-CD:$\gamma$-CD=42:46:12 at $55^{\circ}C$.The optimal pH and temperature of CGTase were 6.0 and $60^{\circ}C$, respectively and the optimal pH and temperature of CDase were 6.0 and $55^{\circ}C$. The molecular weights of the purified CGTase and CDase were estimated to be 65, 000 and 68, 000 dalton, respectively. Among several substrates, $\gamma$-CD was most rapidly hydrolyzed by the purified CDase.

2,3-DHBP dioxygenase was purified from E. coli CK1092 carrying the pcbC gene, which was cloned from 4-chlorobiphenyl-degrading Pseudomonas sp. P20. Purification of this enzyme was done by acetone precipitation, DEAE- Sephadex A-25 ion exchange chromatography, and preparative gel electrophoresis. The molecular weight of subunit was 34 kDa determined by SDS-PAGE, and that of native enzyme was about 270 kDa. It suggests that this enzyme consist of eight identical subunits. This enzyme was specifically active against only 2,3-DHBP as a substrate with 18 $\mu$M of Km value, but not catechol, 3-methylcatechol, 4-methylcatechol and 4-chlorocatechol. The optimal pH and temperature of 2,3-DHBP dioxygenase were pH 8.0 and 40-60$\circ$C. The enzyme was inhibited by Cu$^{2+}$, Fe$^{2+}$ and Fe$^{3+}$ ions, and was inactivated by H$_{2}$0$_{2}$2 and EDTA. The lower concentrations of some organic solvents such as acetone and ethanol don't stabilize the activity of 2,3-DHBP dioxygenase. The enzyme was completely inactivated by adding the reagents such as N-bromosuccinimide, iodine and p- diazobenzene sulfonic acid.

In an effort to understand the role of the conserved domain and of the heterologous one-third part of the carboxy terminal domain of transglutaminase C (TGase II), attempts were made to express TGase II cDNA of human origin in yeast Saccharomyces cerevisiae as in a full-length form as well as in a form of C-terminal truncation. The 2$\mu$-based expression plasmids which contained the TGase II cDNA under the gal inducible promoter were introduced into yeast and the maintenance of the full-length and truncated form of the TGase II gene plasmids were confirmed by Southern blot. The expression of the TGase II gene was analysed by reverse transcription polymerase chain reaction (RT-PCR), and western blot analyses. As assayed by [1,4$^{14}$C]-putrescine incorporation into succinylated casein, the full-lenth as well as the truncated forms of recombinant TGase II showed some catalytic activity. These results indicate that the N-terminal homologous domain of human TGase II retains a catalytically active domain. The level of TGase II expressed in yeast, however, was far lower than satisfactory and other expression system should be sought further chracterization of the enzyme. The negative effect of TGase II on the growth of yeast is interesting with respect to the physiological effect of TGase II in cornification of epidermal keratinocytes.

Isolation, identification, and culture conditions of a lytic enzyme producing microorganism against Lacto- bacillus plantarum were investigated. The selected strain was gram-positive, rod (0.7 $\times$ 2.7 $\mu$m in size), and non-motile. The strain did not have any flagella and spores. According to its cultural and physiological characteristics, the strain was identified as Bacillus sp. The optimal pH and temperature for the production of lytic enzyme were 8.0 and 30$\circ$C, respectively. The maximum enzyme activity showed 1.5 units/ml in the medium composed of 1% peptone and 0.1% NaCl.

For a probiotic yoghurt it is desirable to utilize lactic acid bacteria with a high survival rate and beneficial function to human beings. We have examined a variety of lactic acid bacteria to assess the acid and bile tolerance and antibiotic resistance. In addition, an in vitro culture experiment was performed to evaluate their ability to reduce cholesterol levels in the growth medium. Thirteen strains were selected from in vitro cholesterol assays and fed to Sprague-Dawley rats with a high-cholesterol diet. Among the 13 strains tested, 8 strains were shown to reduce serum cholesterol levels significantly after 24 days of administration in vivo. Rats were fed lyophilized yoghurt powder fermented with a combination of 3 selected strains: Bifidobacterium infantis AM-220, Lactobacillus AM-245, and Styeptococcus MA-1. The levels of total cholesterol and low density lipoprotein were significantly lower (p$\leq$0.05) in rats fed the yoghurt powder compared with control group. These studies suggest that yoghurt fermented with appropriately selected lactic acid bacteria may have a anticholesterolemic effect.

A cytotoxic material was produced by strain No. 5-99 which was isolated from soil. Analyzing the cell wall components, LL-diaminopimelic acid was identified. From the existance of glycine in the cell wall, this strain was identified to Streptomyces sp. which has cell wall chemotype I and peptidoglycan type A3 connected by glycine. So, we named this strain to Streptomyces sp. YJB-599. The Active material was purified through solvent extraction, silica gel column chromatography and crystallized to needle-shaped white -crystal. Analyzing the structure of this crytal by instrumental analysis and database, it was determined to genistein.

An alkaline proteinase produced by Yarrowia lipolytica TH65 was purified by 40-65% ammonium sulfate fractionation, DEAE-cellulose chromatography, and gel filtration with Sephadex G-100 and Sephadex G-75. The purified enzyme was shown as a single band on SDS-PAGE, and its molecular weight 31,500. Optimum temperature and pH were 40$\circ$C and 8.5-9.0, respectively, and the enzyme was stable below 40$\circ$C and in the pH range of 6-8. The enzyme was strongly inhibited by divalent ions, completely by PMSF, and partially by EDTA, EGTA, and phenanthroline. But the inhibitory effect in the presence of EDTA, EGTA and phenanthroline could be reversed by addition of Ca$^{2+}$. Thus, these results indicated that the purified enzyme was an alkaline serine proteinase (E.C. 3.4.21.14).

In the course of screening for new bioactive compounds from oligotrophs in soil, a microorganism, designated as SA-246 and now identified as Micromonospora sp., has been shown to produce a strong antibacterial compound. The active compound was purified from broth filtrate by ethylacetate extraction, silica gel column chromatography, preparative TLC and HPLC, and was identified as crisamicin A based on mass and NMR spectral data. The compound SA- 246 exhibited not only strong antibacterial activity against Gram-positive bacteria but also cytotoxicity against cancer cell lines such as A549 (lung), SK-OV-3 (ovarian), SK-MEL-2 (melanoma), XF498 (central nervous system) and HCT15 (colon).

An amino acid antimetabolite named YS-460 was isolated from the culture filtrate of a newly isolated Actinomycetes identified as Streptomyces sp. Fermentation was carried out in the synthetic medium at 30$\circ$C for 5 days. Purification was done by ion exchange resin, active carbon, silica gel column chromatography and obtained 38 mg of pure active substance per liter of the broth. YS-460, an amino acid like substance, has the molecular formula of C$_{7}$H$_{11}$NO$_{3}$- Its structure determined to be furanomycin by spectral analysis. It is active against some bacteria on a chemically defined medium and reversed competitively by L-isoleucine and non-competitively by L-leucine and L-valine.

Characteristics of ethanol fermentation were investigated during the stationary culture of a killer yeast, Saccharomyces cerevisiae B15-1. Specific ethanol production rate reached the maximum level, 1.203 g-EtOH/g-cell-hr, at 150 g/l of the initial glucose concentration. No big differences were obtained in ethanol fermentability based on the initial sugar concentration below 150 g/l. When 200 g/l of sugar was used, fermentability dropped significantly. Although the final cell mass and the amount of ethanol produced were increased, their increase rates were declined according to the increase of initial sugar concentration. It was found that most of the sugar used below 150 g/l of concentration could be changed to ethanol. However, when 200 g/l of sugar was used, some of them remained in the media even after increase of cell mass and fermentation stopped. The ethanol yield was decreased when initial sugar concentration was high, and were increased when the amount of ethanol produced was increased and finally reached the plateau over 60 g/l of ethanol concentration.

Maximum amount of the aminopeptidase M inhibitors produced by Streptomyces griseoplanus SL20209 in 500 ml-Erlenmeyer flask was accumulated after cultivation for 3 days at 28$\circ$C, thereafter the amount of inhibitors decreased slowly with a pH change to alkaline. Arabinose, xylose, mannose and soluble starch were good carbon sources for the production of the inhibitors. On the other hand, glucose was only good for the cell growth but potently inhibited the production of inhibitors. Natural organic nitrogen sources such as soybean meal, fish meal, gluten meal and peanut powder were good for the production of inhibitors, however, soytone, peptone and inorganic nitrogens such as NH$_{4}$C1 and NH$_{4}$NO$_{3}$ were poor. Inclusion of yeast extract (0.5%, w/v) or K$_{2}$HPO$_{4}$ (0.05%) into the production medium increased the production of inhibitors by accelerating cell growth. The production of inhibitors was slightly increased on the medium containing CaCO$_{3}$ (0.3%) and zeolite (0.5%), respectively. Optimal temperature and initial pH range for the production ot inhibitors were determined to be 28$\circ$C and 6.0-7.0, respectively. Employing two improved production media consisting of 3% arabinose or soluble starch, 2.5% soybean meal, 0.5% yeast extract, 0.05% K$_{2}$HP0$_{4}$, 0.1% CaCO$_{3}$ and 0.3% zeolite (pH 6.8), 1.8-fold increase in the amount of inhibitors was achieved, comparing with the basal medium used.

Microorganisms growing alcoholic distillery wastes were isolated from soil. Of them, the selected strain EL-9 had a capability of accumulating poly-$\beta$-hydroxybutyrate (PHB) when grown in alcoholic distillery wastes. The strain EL-9 was identified as a genus Actinobacillus based on the morphological, cultural, and biochemical characteristics. The strain EL-9 was named temporarily as Actino- bacillus sp. EL-9. The optimal temperature and pH for cell growth of Actinobacillus sp. EL-9 were 30$\circ$C and 7.0, respectively. The optimal medium compositions for cell growth comprised glucose 2%, NH$_{4}$NO$_{3}$ 0.15%, Na$_{2}$HP0$_{4}$-12H$_{2}$O 0.25%, KH$_{2}$PO$_{4}$ 0.25%, MgSO$_{4}$4-7H$_{2}$O 0.15%, FeSO$_{4}$-7H$_{2}$O 0.005%, CaCl$_{2}$-2H$_{2}$O 0.003% and trace element solution 5m/l. To investigate the optimal conditions for PHB production, two-stage culture technique was used. The result showed that the optimal conditions for PHB production are identical those for cell growth. When propionic acid was added as a cosubstrate, PHB/HV copolymer was produced.

Alcoholic distillery wastes are utilized as dual purposes to produce PHB in lower production cost and to reduce the amount of waste to be treated. In this study, various attempts were made to increase PHB production under various conditions by Actinobacillus sp. EL-9 in a shaker culture. The addition of glucose, NH$_{4}$NO$_{3}$ to alcoholic distillery wastes slightly promoted cell mass and PHB production. Enzyme hydrolysis of alcoholic distillery wastes increased the production of PHB than that of untreated waste and acid hydrolysis treatment. The PHB weight in alcoholic distillery wastes was 1.91 g/l. Fermentation process of PHB production reduced the amount of COD value up to 54%, which reduced organic loading rate and capacity of activated sludge system.

For the production of D-lactic acid from DL-2-chloropropionic acid, about 80 strains of bacteria capable of assimilating DL-2-chloropropionic acid as a sole carbon and energy source were isolated from the soil. JH-007 strain that showed the higest productivity of D-lactic acid and didn't produce L-lactic acid from DL-2-chloropropionic acid was selected from them and identified as Pseudomonas sp. The optimal conditions for the production of D-lactic acid from DL-2-chloropropionic acid were examined. The resting cells of JH-007 cultured in LB medium containing 3 g/l of DL-2-chloropropionic acid were used as an enzyme source. The reaction mixtures for the maximal production of D-lactic acid were consist of 10 g/l of resting cells and 3 g/l of DL-2-chloropropionic acid in 125 mM sodium carbonate buffer. The optimal pH for the reaction was 10.0 and the optimal temperature was 30$\circ$C. When 1 g/l of DL-2-chloropropionic acid was added intermittently to the reaction mixture under the above condition, 5.72 g/l of D-lactic acid was produced after incubation of 5 hrs. This amount of D-lactic acid corresponded to a 98.4% yields and the optical purity was 99.8%.

Sediments collected from the Jungnang-cheon and its tributaries were used to enumerate anaerobic bacteria by most probable number (MPN) methods. A simple method was developed to detect ferrous ion in the culture fluid in order to count the number of iron ion reducers, and sulfate-reducing bacteria (SRB) and methanogens were detected by the presence of FeS precipitate in the culture or methane in the head space, respectively. The numbers of iron reducer was in the range of 10$^{7}$ - 10$^{8}$ /g in the sediment of the stream containing higher organic content than the tributaries. The sediments of tributaries were analyzed to contain iron reducers less than 10$^{7}$ cells/g. With one exception the numbers of SRB and methanogens were less than 10$^{3}$ cells/g in the sediment. From these results it is concluded that organics in the sediment support the growth of iron reducers, which out-compete SRB and methanogens.

TFD is a transcription factor database which consists of short functional DNA sequences called as signals and their references. SIGNAL SCAN, developed by Dan S. Prestridge, is used to determine what signals of TFD may exist in a DNA sequence. This program searches TFD database by using a simple algorithm for character string comparison. We developed TFSCAN that aims at searching for signals in an input DNA sequence more efficently than SIGNAL SCAN. Our algorithms consist of two parts, one constructs an automata by scanning sequences of rFD, the other searches for signals through this automata. Searching for signal-related references is radically improved in time by using an indexing method. Usage of TFSCAN is very simple and its output is obvious. We developed and installed a TFSCAN input form and a CGI program in GINet Web server, to use TFSCAN. The algorithm applying automata showed drastical results in improvement of computing time. This approach may apply to recognizing several biological patterns. We have been developing our algorithm to optimize the automata and to search more sensitively for signals.

Cane molasses, the most widely used carbon source for the industrial fermentation of L-lysine, usually contains a high concentration of calcium ions which tend to cause scaling problem in the recovery process. To remove the calcium ions, cane molasses was pretrea ted with sulfuric acid by adjusting the pH to 2.5-3.5. When the pretreated solution was directly heat-sterilized and used in the fermentation, a significant reduction in L-lysine production was observed. In this paper, we proved that sucrose is a superior substrate for L-lysine fermentation to that of glucose or fructose and that the above-mentioned decrease of L-lysine production was caused by the hydrolysis of sucrose in the molasses when the molasses was heat-sterilized at a low pH. The problem was overcome by adjusting the pH of molasses to neutral before sterilization.

Adenosine deaminase inhibitor was extracted from culture broth of Streptomyces sp. strain V-8 with ethylacetate. The ethylacetate extract showed the characteristic UV absorption spectrum of actinomycins at 440-450 nm. The ethylacetate extract was compared with respect to inhibitory behavior against adenosine deaminase from calf intestinal mucosa with actinomycin D, -C complex and actinomycin V. The Ki values for actnomycin D, -C complex, and actinomycin V against adenosine deaminase were determined to be 9.9 $\times$ 10$^{-6}$ M, 9.6 $\times$ 10$^{-6}$ M and 9.3 $\times$ 10$^{-6}$ M, respectively. The Ki value for the ethylacetate extract of culture broth against adenosine deaminase was determined to be 5.7 $\times$ 10$^{-6}$ M. The kinetic parameters of actinomycin D, -C complex, -V and ethylacetate extract of culture broth for adenosine deaminase were as follows:I$_{50}$ = 1.5 $\times$ 10$^{-5}$ M (actinomycin D), 2.7 $\times$ 10$^{-5}$ M (actinomycin C complex), 3.5 $\times$ 10$^{-5}$ M (actinomycin V), 8.9 $\times$ 10$^{-6}$ M (ethylacetate extract of culture broth). The adenosine deaminase was inhibited noncompetitively by ethylacetate extract of culture broth as well as by actinomycin D, -C complex and actinomycin V.