• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.524-534
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• 2017

The development and utilization of crop straw biogas resources can effectively alleviate the shortage of energy, environmental pollution, and other issues. This study performed a continuous batch test at $35^{\circ}C$ to assess the methane production potential and volatile organic acid contents using the modified Gompertz equation. Illumina MiSeq platform sequencing, which is a sequencing method based on sequencing-by-synthesis, was used to compare the archaeal community diversity, and denaturing gradient gel electrophoresis (DGGE) was used to analyze the bacterial community diversity in rice straw, dry maize straw, silage maize straw, and tobacco straw. The results showed that cumulative gas production values for silage maize straw, rice straw, dry maize straw, and tobacco straw were 4,870, 4,032.5, 3,907.5, and $3,628.3ml/g{\cdot}VS$, respectively, after 24 days. Maximum daily gas production values of silage maize straw and rice straw were 1,025 and $904.17ml/g{\cdot}VS$, respectively, followed by tobacco straw and dry maize straw. The methane content of all four kinds of straws was > 60%, particularly that of silage maize straw, which peaked at 67.3%. Biogas production from the four kinds of straw was in the order silage maize straw > rice straw > dry maize straw > tobacco straw, and the values were 1,166.7, 1,048.4, 890, and $637.4ml/g{\cdot}VS$, respectively. The microbial community analysis showed that metabolism was mainly carried out by acetate-utilizing methanogens, and that Methanosarcina was the dominant archaeal genus in the four kinds of straw, and the DGGE bands belonged to the phyla Firmicutes, Bacteroidetes, and Chloroflexi. Silage maize is useful for biogas production because it contains four kinds of straw.

• Asian-Australasian Journal of Animal Sciences
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• 제13권11호
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• pp.1554-1560
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• 2000

Ninety-six crossbred (Large White${\times}$Landrace${\times}$Duroc) pigs, weaned at 35 days of age, were assigned to four dietary treatments in order to investigate the effects of oral antibiotics on the performance and the intestinal microflora of weanling pigs. Pigs were fed either a basal diet, without antibiotics, or the basal diet plus either 50 ppm acetylspiramycin, 50 ppm olaquindox, or 100 ppm bacitracin zinc. The pigs were housed eight per pen with three pens per treatment in an environmentally controlled nursery. Ten days after weaning, three pigs from each treatment were slaughtered and intestinal pH, microflora, and volatile fatty acid concentration were determined. At the end of the 4 week trial, the remaining pigs were weighed and feed consumption was measured. Average daily gains for pigs fed acetylspiramycin, olaquindox, bacitracin zinc and the control diet were 0.43, 0.40, 0.37, and 0.34 kg per day (p=0.001), respectively. Antibiotic addition did not modify feed intake, but acetylspiramycin improved feed conversion (p=0.003). In comparison with the control, acetylspiramycin significantly increased Bifidobacteria numbers in the jejunum (p=0.082) and ileum (p=0.014) and decreased total bacterial counts throughout the intestine (p<0.01 except for the ileum where p=0.079). Acetate production was significantly lower in the cecum (p=0.028) and colon (p=0.079) of pigs fed acetylspiramycin. In addition to increasing numbers of Bifidobacteria in the jejunum (p=0.082) and ileum (p=0.014), olaquindox increased Lactobacillus in the jejunum (p=0.004) and decreased E. coli in the colon (p=0.022). Bacitracin zinc increased Lactobacillus numbers in the jejunum (p=0.004) and Bifidobacterium concentrations in the jejunum (p=0.082) and ileum (p=0.014).

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.1005-1012
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• 2009

Lysozyme and the reduction of metabisulfite addition to red wine were evaluated during a winemaking process and after malolactic fermentation (MLF). Treatment, with lysozyme, of the must from Tempranillo grapes and at the end of alcoholic fermentation (AF) caused the 100% implantation of the inoculated bacterial strain and shortened the duration of MLF by 7 days. At the end of the MLF, wines treated with lysozyme showed lower volatile acidity, color intensity, and biogenic amine content. The differences in color intensity disappeared during wine stabilization. The lysozyme addition after MLF led to lower histamine concentrations in wines. These phenomena occurred irrespective of the lactic acid bacteria (LAB) proliferation control and of the Oenococcus oeni dominant strain identified at this period. The results of this study show the significance of preventive use of lysozyme in vinification of red wine to maintain low histamine levels and ensure a successful implantation of inoculated O. oeni starters.

• 대한환경공학회지
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• 제28권2호
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• pp.144-149
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• 2006

Hexane을 유일 탄소 에너지원으로 하여 농화배양한 배양액으로부터 hexane 분해능이 우수한 EH741 균주를 순수 분리 동정하였고, 분리균주에 의한 hexane 생분해 특성을 조사하였다. EH741 균주는 Rhodococcus sp.로 동정되었고, 액상 배양계에서 hexane 용해도를 향상시키기 위해 첨가한 계면활성제 Pluronic F68(PF68)은 hexane 생분해 속도에 영향을 미치지 않았다. Hexane을 유일 탄소원으로 첨가한 무기염 배지에서 EH741의 최대 비성장속도(${\mu}_{max}$)값은 $0.04h^{-1}$이었고, 최대 hexane 분해속도($V_{max}$)와 포화상수($K_s$)는 각각 $161{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ 및 10.5 mM이었다. Rhodococcus sp. EH741은 hexane 처리를 위한 생물학적 공정에 유용하게 활용될 것으로 사료된다.

• Environmental Engineering Research
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• 제19권1호
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• pp.83-89
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• 2014

The effects of initial solid concentration and microwave irradiation (MWI) time on the hydrolysis of waste activated sludge (WAS) were investigated. MWI time strongly influenced WAS hydrolysis for all initial solid concentrations of 8.20, 31.51, and 52.88 g VSS/L. For all WAS, the volatile suspended solids (VSS) solubilization degree ranged from 35.6% to 38.4% during a total MWI time of 10 min. Soluble chemical oxygen demand (SCOD) concentration increased at a rate proportional to the decrease of VSS during the MWI. However, the clearly different VSS solubilization patterns that were observed during the MWI were explained by the 2-step hydrolysis of WAS, consisting of the initial disintegration of the easily degradable part of the sludge, followed by the subsequent disintegration of the hardly degradable part of the sludge. WAS hydrolysis rates for 3 to 6 min of MWI were significantly lower than those for less than 3 min, or more than 6 min. From these results, 3 min MWI time and WAS of 31.51 g VSS/L (centrifugal thickener WAS) showed the most efficient hydrolysis of WAS at 36.0%. The profiles of total nitrogen (T-N) concentrations corresponded well to the SCOD increases in terms of the empirical formula of bacterial cell mass ($C_5H_7O_2N$). The negligible T-N increase and pH decrease during WAS hydrolysis by MWI will allow the application of this process to subsequent biological processes, such as anaerobic digestion.

• 한국수산과학회지
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• 제3권4호
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• pp.207-212
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• 1970

멸치절임의 숙성 및 저장 중의 효소 활성 VBN, 세균수, 식염 함유량, 산도, amino-N pH 그리고 지방의 산가에 다음과 같은 결과를 얻었다. 1) Protease 활성은 염수 염장 중에는 증가하고 절임 중에는 식초산의 영향으로 감소하고 이후 차차 거의 일정하게 변화하며 이에 따라 amino-N는 대개 증가하여 숙성한다. 2) Lipase 활성은 염수 염장 중에는 감소하며 vinegar의 첨가로 일단 증가하였다가 절임중에는 증감의 일정한 경향을 볼 수 없다. 그리고산도는 대개 증가하고 있다. 3) VBN와 NaCl 농도는 염수 염장 중에는 급격히 증가하고 절임중에서는 VBN는 완만한 증가를 하며 NaCl 농도는 기의 변화가 없었다. 4) 세균수는 염수 염장함으로써 줄었다가 다시 증가하며 절임함으로써 급격한 감소를 보이고 그 이후에는 일정한 수를 유지 하였다. 5) 절임 제품의 저장성을 유지하기 위해서는 육질의 산도가 $2\%$ 이상이 되도록 vinegar의 산도를 높혀 주어야한다. 6) 염수 염장하는 기간은 8일이 적합하였으며 VBN, 산도, amino-N, lipase 활성 및 관능 검사 성적을 보아서 절임한 후 47일까지 보장할 수 있고 32일 때가 가장 맛이 좋았다.

• 한국축산식품학회지
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• 제36권4호
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• pp.476-486
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• 2016

This study investigated the effect of the powder produced by ball-milling the outer layer of annatto (Bixa orellana L.) seeds on the physicochemical properties as well as the antioxidant and antimicrobial activities of pork patties over 14 d of refrigerated storage (4±1℃). Five pork patty treatments were produced containing three different concentrations of annatto seeds, 0.1, 0.25 and 0.5% (ANT0.1, ANT0.25, ANT0.5), 0.1% ascorbic acid (AA0.1), and a control (CTL). Based on the results, annatto seed powder appeared to show antioxidant activity. The Hunter color values of pork patties were affected by the addition of annatto seed powder, which increased the redness and yellowness values, but decreased the lightness of the patties (p<0.05). To evaluate the antioxidative effects of annatto on pork patties, thiobarbituric acid reactive substances (TBARS) and peroxide values (POV) were analyzed over 14 d of refrigerated storage. Treatments containing annatto seed showed lower TBARS and POV than control (CTL) samples (p<0.05). The volatile basic nitrogen (VBN) of the pork patties containing annatto seeds were lower than that of CTL at the end of storage (p<0.05). Although no differences in total bacterial counts were observed between control and treated patties, those containing annatto seeds had lower microbial counts for Enterobacteriacease than CTL or AA 0.1%. Therefore, annatto seed powder might be a good source of natural antioxidants for the production of meat products.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.661-672
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• 1998

Two experiments were conducted to examine the effects of a range of concentrations of ruminal fluid ammonia ($NH_3$-N) on forage digestibility, microbial growth efficiency and the mix of microbial species. Urea was either continuously infused directly into the rumen of sheep fed 33.3 glh of oaten chaff (Exp. I) or sprayed onto the oaten chaff (750 g/d) given once daily (Exp. 2). Concentrations of $NH_3$-N increased with incremental addition of urea (p < 0.01). Volatile fatty acids (VFA) concentrations and 24 h in sacco organic matter digestibility in the rumen were higher when supplemental urea was given (p < 0.01). The (C2 + C4) : C3 VFA ratio was lower (p < 0.05) when $NH_3$-N was above 200 mgN/I. The fungal sporangia appearing on oat leaf blades were significantly higher when urea was supplemented, indicating that $NH_3$-N was a growthlimiting nutrient for fungi at levels of $NH_3$-N below 30 mgN/l. The density of protozoa was highest when $NH_3$-N concentrations were adjusted to 30 mgN/I for continuously fed ($4.4{\times}10^5/ml$) and to 168 mgN/1 for once daily feeding ($2.9{\times}10^5/ml$). Thereafter increasing concentrations of $NH_3$-N, were associated with a concomitant decline in protozoal densities. At the concentration of $NH_3$-N above 200 mgN/l, the density of protozoa was similar to the density of protozoa in ruminal fluid of the control sheep ($1.8{\times}10^5/ml$). The efficiency of net microbial protein synthesis in the rumen calculated from purine excretion was 17-47% higher when the level of $NH_3$-N was above 200 mgN/1. The possibilities are that 1) there is less bacterial cell lysis in the rumen because of the concomitant decrease in the protozoal pool and/or 2) microbial growth per se in the rumen is more efficient with increasing $NH_3$-N concentrations.

• Asian-Australasian Journal of Animal Sciences
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• 제26권12호
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• pp.1781-1789
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• 2013

Many studies have been carried out with respect to packaging methods and temperature conditions of beef. However, the effects of packaging methods and temperature conditions on the quality characteristics have not been extensively studied in low-grade beef. Low-grade beef samples were divided into 3 groups (C: ziplock bag packaging, T1: vacuum packaging, and T2: modified atmosphere packaging (MAP), $CO_2/N_2$ = 3:7) and samples were stored at $4^{\circ}C$ for 21 days. The water-holding capacity (WHC) was significantly lower in T1 than in the other samples up to 14 days of storage. The thiobarbituric acid reactive substances and volatile basic nitrogen values were significantly lower in T1 and T2 than in C after 7 to 14 days of storage. The total bacterial counts were significantly lower in T1 and T2 than in C after 14 days of storage. In a sensory evaluation, tenderness and overall acceptability were significantly higher in T1 and T2 than in C at the end of the storage period (21 days). We propose that the MAP method can improve beef quality characteristics of low-grade beef during cold storage. However, the beneficial effects did not outweigh the cost increase to implement MAP.

• Asian-Australasian Journal of Animal Sciences
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• 제33권10호
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• pp.1590-1598
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• 2020

Objective: The objective of this study was to evaluate the effects of lysophospholipids (LPL) supplementation on rumen fermentation, degradability, and microbial diversity in forage with high oil diet in an in vitro system. Methods: Four experimental treatments were used: i) annual ryegrass (CON), ii) 93% annual ryegrass +7% corn oil on a dry matter (DM) basis (OiL), iii) OiL with a low level (0.08% of dietary DM) of LPL (LLPL), and iv) OiL with a high level (0.16% of dietary DM) of LPL (HLPL). An in vitro fermentation experiment was performed using strained rumen fluid for 48 h incubations. In vitro DM degradability (IVDMD), in vitro neutral detergent fiber degradability, pH, ammonia nitrogen (NH₃-N), volatile fatty acid (VFA), and microbial diversity were estimated. Results: There was no significant change in IVDMD, pH, NH₃-N, and total VFA production among treatments. The LPL supplementation significantly increased the proportion of butyrate and valerate (Linear effect [Lin], p = 0.004 and <0.001, respectively). The LPL supplementation tended to increase the total bacteria in a linear manner (p = 0.089). There were significant decreases in the relative proportions of cellulolytic (Fibrobacter succinogenes and Ruminococcus albus) and lipolytic (Anaerovibrio lipolytica and Butyrivibrio proteoclasticus) bacteria with increasing levels of LPL supplementation (Lin, p = 0.028, 0.006, 0.003, and 0.003, respectively). Conclusion: The LPL supplementation had antimicrobial effects on several cellulolytic and lipolytic bacteria, with no significant difference in nutrient degradability (DM and neutral detergent fiber) and general bacterial counts, suggesting that LPL supplementation might increase the enzymatic activity of rumen bacteria. Therefore, LPL supplementation may be more effective as an antimicrobial agent rather than as an emulsifier in the rumen.