• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.5
• /
• pp.303-310
• /
• 2014

This study investigated the reduction of food waste through the slurry phase decomposition in a source of food waste by microorganisms. The reactor used in the experiment was composed of both woodchip with wood material and sponges with polyurethane material as media of attached microorganisms, and food waste was mixed with a constant cycle consisted of a stirring device. During the experimental period of 100 days, the change in weight over the cumulative total amount of food waste added was reduced by 99%. Approximately, 1% of the residual food waste could be inherently recalcitrant materials (cellulose, hemicellulose, lignin, etc.) and thus was thought to be the result of the accumulation. The initial pH in wastewater generated from food waste was low with 3.3 and after 24 hours treatment this pH was increased to 5.8. The concentrations of COD, BOD, SS, salinity, TN and TP were gradually decreased. Food waste decay was proceeded by the seven species microorganisms identified and confirmed in this study, making a slurry phase and thus reducing residual food wastes. In the initial phase, the microbial population was approximately $3.3{\times}10^4$ cell/mL, and after 15 days this population was a constant with $5.1{\times}10^6$ cell/mL which means a certain stabilization for the reduction of food wastes. From these results, it can be considered that organic matter decomposition as well as the weight loss of food wastes by microorganisms is done at the same time.

• Microbiology and Biotechnology Letters
• /
• v.5 no.1
• /
• pp.18-23
• /
• 1977

Experiments were carried out to pursue the availability and the feasibility of utilizable cellulosic materials as substrate for the production of cellulosic single cell protein. The resuluts were obtained as fellows. 1. Effects of carbolydrates as a sole carton source on the growth of Cellulomonas flavigena KIST 321 were examined. The result showed that cellulose and xylose would be most utlizable for cell mass production. 2. Alkaline treated waste papers and clothes resulted in good growth of the organism than intact ones did. However the waste papers as substrate of cellulosic fermentation were not digestible, even if the meterial was treated with alkalies. 3. Rice straw, rape straw and panic grass appeared to be good substrates for the cell mass production. 4. Leaves were proved to be a good substrate for the cell mass production, but wood sawdust was hardly digested by merely alkaline treatment. 5. When cellulosic wastes as the substrate were examined into the concentration of alkaline solution, the result suggested that the best productivity of cell mass from cellulosic materials was obtained on treatment with 0.8∼1.0％ NaOH solution. 6. The productivity of cell mass was increased by washing out with water after alkaline treatment of newspaper, pine sawdust, lime sawdust and pine leaf.

• Journal of Ecology and Environment
• /
• v.29 no.6
• /
• pp.565-572
• /
• 2006

This study examined the decomposition of blades and culms of aquatic emergent plant species, Zizania latifolia, Phragmites communis and Typha angustata, which were the most frequent in Lake Paldang. The experiment was carried out from July to December, 2005 in fresh water of lake Paldang using litter bag method. The litter bags had 1.2 mm mesh size and were suspended at 1 m depth of water surface. Remaining mass of blades and culms of each species after 97 days was 21.2% and 22.6% of initial mass in Z. latifolia, 32.5% and 56.4% in P. communis and 44.7% and 38.1 % in T. angustata, respectively. The plant tissue having high N concentration and low C/N exhibited the faster decay rate than the others. However, the tissue of high content of lignin, cellulose, lignin:N, and cullulose:N showed a slow decomposition rate. Water temperature was the most effective environmental factor on the emergent macrophyte litter decomposition in aquatic ecosystems. According to the water temperature, DO, $NO_3^-$-N, and total phosphate concentration were changed in the linear way. The mass loss of plant tissue of emergent macrophytes showed positive relationship with P concentration in water. The experiments on the decomposition of the litter using different mesh sized litter bag did not show significant differences between them. The results suggest that the decomposition of emergent macrophytes in fresh water of lake Paldang, which showed features of lentic and lower part of a stream, was affected by microbial activities better than the micro-invertebrates such as shredders.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.7
• /
• pp.957-966
• /
• 2017

Objective: To understand the dynamic structure, function, and influence on nutrient metabolism in hosts, it was crucial to assess the genetic potential of gut microbial community in yaks of different ages. Methods: The denaturing gradient gel electrophoresis (DGGE) profiles and Illumina-based metagenomic sequencing on colon contents of 15 semi-domestic yaks were investigated. Unweighted pairwise grouping method with mathematical averages (UPGMA) clustering and principal component analysis (PCA) were used to analyze the DGGE fingerprint. The Illumina sequences were assembled, predicted to genes and functionally annotated, and then classified by querying protein sequences of the genes against the Kyoto encyclopedia of genes and genomes (KEGG) database. Results: Metagenomic sequencing showed that more than 85% of ribosomal RNA (rRNA) gene sequences belonged to the phylum Firmicutes and Bacteroidetes, indicating that the family Ruminococcaceae (46.5%), Rikenellaceae (11.3%), Lachnospiraceae (10.0%), and Bacteroidaceae (6.3%) were dominant gut microbes. Over 50% of non-rRNA gene sequences represented the metabolic pathways of amino acids (14.4%), proteins (12.3%), sugars (11.9%), nucleotides (6.8%), lipids (1.7%), xenobiotics (1.4%), coenzymes, and vitamins (3.6%). Gene functional classification showed that most of enzyme-coding genes were related to cellulose digestion and amino acids metabolic pathways. Conclusion: Yaks' age had a substantial effect on gut microbial composition. Comparative metagenomics of gut microbiota in 0.5-, 1.5-, and 2.5-year-old yaks revealed that the abundance of the class Clostridia, Bacteroidia, and Lentisphaeria, as well as the phylum Firmicutes, Bacteroidetes, Lentisphaerae, Tenericutes, and Cyanobacteria, varied more greatly during yaks' growth, especially in young animals (0.5 and 1.5 years old). Gut microbes, including Bacteroides, Clostridium, and Lentisphaeria, make a contribution to the energy metabolism and synthesis of amino acid, which are essential to the normal growth of yaks.

• Microbiology and Biotechnology Letters
• /
• v.6 no.1
• /
• pp.1-8
• /
• 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
• /
• v.9 no.2
• /
• pp.65-69
• /
• 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
• /
• v.4 no.3
• /
• pp.105-110
• /
• 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％.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.6
• /
• pp.988-1001
• /
• 1999

The rumen ecosystem is increasingly being recognized as a promising source of superior polysaccharide-degrading enzymes. They contain a wide array of novel enzymes at the levels of specific activities of 1,184, 1,069, 119, 390, 327 and $946{\mu}mol$ Reducing sugar release/min/mg protein for endoglucanase, xylanase, polygalactouronase, amylase, glucanase and arabinase, respectively. These enzymes are mainly located in the surface of rumen microbes. However, glycoside-degrading enzymes (e.g. glucosidase, fucosidase, xylosidase and arabinofuranosidase, etc.) are mainly located in the rumen fluid, when detected enzyme activities according to the ruminal compartments (e.g. enzymes in whole rumen contents, feed-associated enzymes, microbial cell-associated enzymes, and enzymes in the rumen fluid). Ruminal fungi are the primary contributors to high production of novel enzymes; the bacteria and protozoa also have important functions, but less central roles. The enzyme activities of bacteria, protozoa and fungi were detected 32.26, 19.21 and 47.60 mol glucose release/min/mL mediem for cellulose; 42.56, 14.96 and 64.93 mmol xylose release/min/mL medium after 48h incubation, respectively. The polysachharide-degrading enzyme activity of ruminal anaerobic fungi (e.g. Neocallimastix patriciarum and Piromyces communis, etc.) was much higher approximately 3~6 times than that of aerobic fungi (e.g. Tricoderma reesei, T. viridae and Aspergillus oryzae, etc.) used widely in industrial process. Therefore, the rumen ecosystem could be a growing source of novel enzymes having a tremendous potential for industrial applications.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.1
• /
• pp.5-11
• /
• 1993

First crop of alfalfa (Medicago sativa L.) was harvested, wilted and ensiled with or without NaOH or $NH_3$, and fed to three rumen fistulated goats in a $3{\times}3$ Latin-square design. Each alkali treatment (2.44% of alfalfa dry matter) was made by spraying its solution prior to ensiling. Silage pH, $NH_3-N$ and butyric acid concentration were increased with each alkali addition, and NaOH-treated silage showed the lowest chemical quality. Compared with untreated silage, digestibilities of organic matter, ADF and cellulose were depressed by both alkali treatments, and the reductions in NaOH-treated silage were significant. Crude protein digestibility was also significantly decreased in NaOH-treated silage, but the goats receiving the silage excreted less nitrogen in urine than those on the other two silages. Nitrogen retention of goats was not different among the treatments. Ruminal solubility and potential degradability of dry matter and nitrogen determined with the in situ bag technique were reduced, and rate of degradation of the two components were increased by the NaOH treatment. Addition of $NH_3$ provided ruminal soluble nitrogen to the silage, but the rate of degradation was similar to that of untreated silage. These results suggest that NaOH treatment would denature the protein and reduce the susceptibility to microbial degradation in the rumen, while no positive effect of alkali treatment on fiber digestion and nitrogen utilization was observed in this study.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.1
• /
• pp.29-34
• /
• 2005

W/O/W (water-in-oil-in-water) type multiple emulsion was applied to improve the storage stability of an antagonistic microorganism, Burkholderia gladioli. Encapsulation of microorganism into a W/O/W emulsion was conducted by using a two-step emulsification method. W/O/W emulsion was prepared by the incorporation of B. gladioli into rapeseed oil and the addition of polyglycerin polyriconolate (PGPR) and castor oil polyoxyethylene (COG 25) as the primary and secondary emulsifier, respectively. Microcrystalline cellulose was used as an emulsion stabilizer. To evaluate the usefulness of W/O/W emulsion formulation as a microbial pesticide for controlling the bacterial wilt pathogen (Ralstonia solanacearum), the storage stability and antagonistic activity of emulsion formulation were tested in vitro. The storage stability test revealed that the viability of formulated cells in emulsion was higher than that of unformulated cells in culture broth. At $4^{\circ}C$, the viabilities of formulated cells and unformulated cells at the end of 20 weeks decreased to about 2 and 5 log cycles, respectively. At $37^{\circ}C$, the viability of formulated cells decreased to only 2 log cycles at the end of storage. On the other hand, the viable cells in culture broth were not detected after 13 weeks. In activity test, formulated cells in emulsion were more effective in inhibiting the growth of pathogen than unformulated cells in culture broth. Unformulated cells completely lost their antagonistic activity during storage under similar conditions. The W/O/W multiple emulsion formulation was shown to be useful as the novel liquid formulation for biological control.