• 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.

• Korean journal of food and cookery science
• /
• v.24 no.1
• /
• pp.99-105
• /
• 2008

Laver-wrapped rice and laver-wrapped rice containing a vinegar blend (vinegar:sugar:water:salt = 5:2:2:1) were prepared and their degrees of aging from 10 to $30^{\circ}C$, total cell numbers, and total coliforms were examined and compared. The total cell numbers of the laver-wrapped rice increased to 1 log cfu/g at 36 hours, and the total cell numbers of the laver-wrapped rice with vinegar had increased to within 48 hours. At $20^{\circ}C$ for 24 hrs, the total cell numbers for the laver-wrapped rice had increased to 5 log cfu/g: whereas trhe total cell numbers of the laver-wrapped rice with vinegar(5ml of vinegar marinade mixed into 100g of steamed rice), stored at the same conditions had not increased. In the vinegar-marinated rice (2ml/100g rice), microorganisms appeared at 18 hours. However, at the concentration of 5ml/l00g of rice, microorganisms were not observed at 24 hours. Coliforms did not appear in the laver-wrapped rice nor in the laver-wrapped rice with vinegar(prepared at 10ml/100g) until 48 hours. When stored at 10 and $20^{\circ}C$, no microorganisms were found in the laver-wrapped rice with vinegar until 48 hours, respectively. However, at $30^{\circ}C$, microorganisms were observed in the laver-wrapped rice from 24 hours, and from 48 hours in the laver-wrapped rice with vinegar. These results suggest that laver-wrapped rice should be consumed within one day. The number of microorganisms inside the laver-wrapped rice reached 6 log cfu/g by 24 hours, but the increase in the laver-wrapped rice with vinegar was slower. The aging(% damaged starch) of the laver-wrapped rice with vinegar(5ml/100g the rice) stored at $20^{\circ}C$ was reduced, with 3% damaged starch at 24 hours. Consumer evaluations revealed that the laver-wrapped rice prepared with 5ml of the vinegar blend received higher scores for flavor, taste, texture, and overall acceptance as compared to the control. In particular, significantly higher scores were given for taste, texture, and overall acceptability. In summary, the laver-wrapped rice with vinegar had an extended shelf-life(more than 1 day) at storage temperatures of $20-30^{\circ}C$, as well as reduced retrogradation. In addition, based on consumer evaluations, adding vinegar to laver-wrapped rice laver is effective for increasing overall acceptability.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.73-81
• /
• 2018

The giant mealworm beetle, Zophobas atratus (Coleoptera: Tenebrionidae), is a tropical beetle. As this beetle can be used as an ingredient in animal feed, the effects of brewer's spent grain (BSG) on the development and nutritional value of Z. atratus were investigated. As results, there were no significant differences on the larval survival rate, body weight, and duration at different content of BSG, mixed with conventional feed, wheat bran (WB). Based on these results, BSG can be mixed with wheat bran as a Z. atratus food ingredient without any problems. The nutritional value was compared between 100% wheat bran control and 50% BSG experimental groups. The moisture, crude protein, carbohydrates, and amino acids were 1.1-1.4 times higher in the 50% BSG group. In the BSG group, the linoleic acid content was 1.6 times higher than that in the control group. In the wheat bran group, the oleic acid content was 38.4%, which was 1.3 times higher than that in the BSG group. As minerals, the control and BSG groups showed high potassium and phosphorus contents. In terms of hazardous materials, four heavy metals (lead, mercury, arsenic, and cadmium) and two microorganisms (Escherichia coli and Salmonella spp.) were not detected. There were no significant differences in developmental characteristics between the wheat bran and BSG mixed groups, and the nutritional values were better in the BSG mixed group. Therefore, BSG can be used as alternative food source for rearing Z. atratus.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.1
• /
• pp.100-110
• /
• 2020

Objective: The objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue. Methods: TMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0: 40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter. The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue. Results: Both A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 10⁵ cfu/g fresh matter (FM) and below the detection limit, respectively. The lactic acid bacteria count increased to 10⁹ cfu/g FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment. Conclusion: Proteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

• Journal of Food Hygiene and Safety
• /
• v.3 no.4
• /
• pp.233-239
• /
• 1988

Vegetable mixed codiments, commercial products prepared using soybean,paste and natto, respectively as the ingredients, were used ina study to evaluate the efficacy of gamma irradiationas a means of decontamination and the emphasis was placed upon the determination of the effect of irradiation on the microbiological and some physicochemical properties of the samples. The number of microorganisms contaminated ranged from $10^{6}\;to\;10^{7}$ cells per gram in mesophilic total bacteria, which were composed of thermophilts and acid tolerant bacteria by over 90%. They were reduced by 3 to 4 log cycles with irradiation at 10 kGy. Gamma irradiation at 5 kGy could eliminate the microbial populations of yeasts and molds ($10^{2}\;to\;10^{3}$ cells per gram) and coliforms ($10^{6}\;to\;10^{6}$ cells per gram of natto condiments). However, total destruction of microorganisms in soybean-paste and natto condiments was shown to be possible at a dose-range more than 10 kGy. Irradiationup to 10 kGy was not detrimental to the physicochemical properties of the sample, such as pH. amino nitrogen, rancidity and color, even though some change was brought about in the content of sulfur-containing amino acids.

• Applied Chemistry for Engineering
• /
• v.33 no.2
• /
• pp.179-187
• /
• 2022

In this study, the synthesis of 1,2-dodecylaminopropanediol (1,2-DDAP) having a 12 carbon chain length and an amine group was designed to improve the preservation and hydrophilicity of 1,2-alkanediol-based compounds. 1,2-DDAP was prepared by reacting dodecylamine (DDA) with 3-monochloro-1,2-propanediol (3-MCPD) in an ethanol solvent at 40 ℃, and its yield and purity were about 56% and 98%, respectively, under a reaction condition of 2 h and a DDA:3-MCPD molar ratio of 1:0.8. The antimicrobial effect of 1,2-DDAP showed the values of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against microorganisms at concentrations of 10 to 100 times lower than those of 1,2-octanediol(1,2-ODIOL) or 1,2-decanediol (1,2-DDIOL). Based on the hydrophilic properties of 1,2-DDAP, mixed preservatives were prepared by adding small amounts of 1,2-ODIOL or 1,2-DDIOL, which are poorly soluble in water, with 1,2-DDAP. Mixed preservatives exhibited an effect of inhibiting microorganisms equal to or greater than that of 1,2-DDAP alone in antimicrobial activity tests. As a result of confirming the preservation effect in lotion (cosmetic formulation) for application, 1,2-DDAP showed similar antimicrobial activity at concentrations of 0.3 to 0.6 times lower than that of 1,2-ODIOL or 1,2-DDIOL. Therefore, it is considered that the use of 1,2-DDAP alone and the mixed use with small amounts of 1,2-ODIOL or 1,2-DDIOL can be a good alternative to preservatives in the product.

• Microbiology and Biotechnology Letters
• /
• v.29 no.2
• /
• pp.115-121
• /
• 2001

Biological Treatment of Wastewater Containing Chlorinated Phenols by a Mixed Culture. Lee, Wan-Seok1, Sang-Wook Jung, Chan-Sun Park, Byung-Dae Yoon, Jang-Eok Kim\ and Hee-Mock Oh*. Environmental Bioresources Laboratory, Korea Research Institute of Biosicence and Biotechnology, Taejon, Korea, 1 Department of Agricultural Chemistry, Kyungpool< National University, Taegu, Korea - The biodegradation of chlorinated phenols in an artificial wastewater was investigated using a mixed culture. The mixed culture was composed of 8 microorganisms isolated from the soil contaminated with various chlorinated phenols. Pseudomonas sp. BM as a main constituent of a mixed culture was Gram-negative, catalase- and oxidase-positive, and rod-shaped, and did not grow at 41°C. It degraded 99% of initial 500 mg!1 of pentachlorophenol (PCP) in the minimal salts medium as a sole source of carbon and energy within 3 days. The degradation efficiency of Pseu.domon.as sp. BM was not affected by the other organic carbon and nitrogen compounds. Pseudomonas sp. BM was able to grow in a broad range of pH 5 - 8, and degrade 2,000 mg/1 PCP. In the experiment with an artificial wastewater containing chlorinated phenols, the degradation efficiency of the mixed culture was the range of 73% (2,4-dichlorophenol) -96% (2-chlorophenol) during an incubation of 7 days. In a continuous culture experiment, the degradation efficiency of mixed culture plus activated sludge was about 2 times higher than that of the control containing only activated sludge. These results indicate that it is possible to apply the mixed culture to other wastewaters containing chlorinated phenols. Key words: Biodegradation, chlorinated phenols, pentachlorophenol, Pseudomonas sp. BM

• Microbiology and Biotechnology Letters
• /
• v.27 no.3
• /
• pp.236-245
• /
• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).

• Journal of Microbiology and Biotechnology
• /
• v.12 no.5
• /
• pp.801-806
• /
• 2002

A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

• Journal of Environmental Science International
• /
• v.28 no.7
• /
• pp.607-615
• /
• 2019

The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale's experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 - 0.134 mg $NO_3{^-}-N/mg$ MLVSS (mixed liquor volatile suspended solid)${\cdot}day$. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index ($SVI_{30}$) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.