• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.989-1001
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• 2023

The study evaluated the effects of dietary fiber and energy levels administered during two growing periods (d 0-28 and d 29-56) for pigs exposed to a high temperature. A total of 96 growing pigs were used in six treatments as: Two treatments in thermoneutral temperature (21℃-24℃) with dietary energy of 3,300 and the inclusion of high or low fiber, two treatments in heat stress (30℃-34℃) with dietary energy of 3,300 and the inclusion of high or low fiber, and two treatments in heat stress with dietary energy of 3,450 and the inclusion of high or low fiber. Among standard energy level treatments, heat-stressed pigs showed lower average daily gain (ADG), feed intake, digestibility of dry matter, gross energy, crude protein, and crude fiber in phases 1 and 2. Moreover, higher concentrations of acetate, propionate, butyrate, and total short-chain fatty acid (SCFA) in feces were shown in pigs fed high fiber diets. There was a negative interaction between dietary fiber and energy for the fecal concentration of isobutyrate in phase 1 and valerate in phase 2. Pigs in heat stress treatments showed a higher rectal temperature, respiratory rate, hair cortisol, plasma zonulin, and fecal lipocalin-2. Among heat stress treatments, the overall ADG was increased in pigs fed high fiber. Pigs fed high dietary fiber showed a greater concentration of acetate, propionate, butyrate, and total SCFA. High fiber treatments decreased plasma zonulin. In conclusion, the inclusion of beet pulp, soluble fiber, at the level of 4% looks necessary in pigs diet during heat stress.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.281-288
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• 2002

Recombinant Escherichia coli strain harboring the ${\lambda}$pR-pL promotor and heterologus poly-${\beta}$-hydroxybutyrate (PHB) biosynthesis genes was used to investigate the effect of culture conditions on the efficient PHB production. The expression of phb genes was induced by a temperature upshift from $33^{\circ}C\;to\;38^{\circ}C$. The protein expression levels were measured by using two-dimensional electrophoresis, and the enzyme activities were also measured to understand the effect of culture temperature, carbon sources, and the dissolved oxygen (DO) concentration on the metabolic regulations. AcetylCoA is an important branch point for PHB production. The decrease in DO concentration lowers the citrate synthase activity, thus limit the flux toward the TCA cycle, and increase the flux for PHB production. Since NADPH is required for PHB production, the PHB production does not continue leading the overproduction of acetate and lac-tate. Based on these observations, a new operation was considered where DO concentration was changed periodically, and it was verified its usefulness for the efficient PHB production by experiments.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.687-693
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• 1992

The study was conducted to investigate the effect of soybean meal (SBM) supplementation on the voluntary intake of rice straw and ruminal fermentation characteristics. Balance trials were conducted with three Hapanese Corriedale wethers fed a rice straw alone (control), rice straw supplemented with 75 and 150 g of SBM/day in a $3{\times}3$ latin square design. Voluntary intake of rice straw in sheep fed both levels of SBM supplemented diets was significantly higher (p<0.05) than that in sheep fed control diet. Crude protein digestibility was significantly increased (p<0.05), but organic matter, crude fibre, neutral detergent fibre and acid detergent fibre digestibilities were not affected by SBM supplementation. Nitrogen balance was positive in sheep on both levels of SBM supplemented diets, but negative in animals on the control diet. Rumen ammonia and blood urea-nitrogen concentrations increased (p<0.05) as increasing level of SBM. Total volatile fatty acids, acetate, propionate, butyrate and valerate concentrations in rumen fluid were also significantly increased (p<0.01), but ruminal pH was decreased (p<0.05) by SBM supplementation.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.629-638
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• 2014

This study describes an alternative mixed culture fermentation technology to anaerobically convert lignocellulosic biomass into butyric acid, a valuable product with wide application, without supplementary cellulolytic enzymes. Rice straw was soaked in 1% NaOH solution to increase digestibility. Among the tested pretreatment conditions, soaking rice straw at $50^{\circ}C$ for 72 h removed ~66% of the lignin, but retained ~84% of the cellulose and ~71% of the hemicellulose. By using an undefined cellulose-degrading butyrate-producing microbial community as butyric acid producer in batch fermentation, about 6 g/l of butyric acid was produced from the pretreated rice straw, which accounted for ~76% of the total volatile fatty acids. In the repeated-batch operation, the butyric acid production declined batch by batch, which was most possibly caused by the shift of microbial community structure monitored by denaturing gradient gel electrophoresis. In this study, batch operation was observed to be more suitable for butyric acid production.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.57-63
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• 2003

Using fungal (Fusarium solani f. pisi) and bacterial (Pseudomonas mendocina) cutinases, the initial hydrolysis rate of p-nitrophenyl esters was systematically estimated for a wide range of enzyme and substrate concentrations using a 96-well microplate reader. Both cutinases exhibited a high substrate specificity; i.e. a high hydrolytic activity on p-nitrophenyl butyrate (PNB), yet extremely low activity on p-nitrophenyl palmitate (PNP). When compared to the hydrolysis of PNB and PNP by other hydrolases [lipases and esterases derived from different microbial sources, such as bacteria (Pseudomonas cepacia, Psedomonas furescens, Baciilus stearothermophilus), molds (Aspeillus niger, mucor miehei), and yeasts (Candida rugosa, Candida cylindracea)], the above substrate specificity would seem to be a unique characteristic of cutinases. Secondly, the hydrolytic activity of the cutinases on PNB appeared much faster than that of the other hydrolytic enzymes mentioned above. Furthermore, the current study proved that even when the cutinases were mixed with large amounts of other hydrolases (lipases or esterases), the Initial hydrolysis rate of PNB was determined only by the cutinase concentration for each PNB concentration. This property of cutinase activity would seem to result from a higher accessibility to the substrate PNB, compared with the other hydrolytic enzymes. Accordingly, these distinct properties of cutinases may be very useful in the rapid and easy isolation of various natural cutinases with different microbial sources, each of which may provide a novel industrial application with a specific enzymatic function.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.217-233
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• 1998

Milk yield and its composition is governed by level of nutrition and the composition of diet. Higher concentrate input improves milk yield, whereas its input at moderate levels improves yield of milk fat. High level of dietary protein improves dry matter intake and milk production, however, CP content above 14% has less advantage. Milk yield is enhanced by the feeding of cottonseed and soyabean meal, whereas milk fat increases by the supplementation of cottonseed. Dietary fat increases energy intake, production of milk and milk fat. Quality and quantity of feeds consumed affect fermentation patterns in rumen. Among the rumen metabolites, volatile fatty acids (VFA) content and propionate proportion have been related positively with milk yield, whereas proportion of acetate and butyrate have been related positively with milk fat content. Dietary carbohydrates through the source of sugar, starch, roughage and fibre affect VFA concentration in rumen. Therefore, concentration of volatile fatty acids could be altered to the advantage of consumer through judicious manipulation of diet.

• Journal of Microbiology and Biotechnology
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• v.19 no.3
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• pp.291-298
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• 2009

The carbon metabolism of newly isolated Clostridium tyrobutyricum JM1 was investigated at varying initial glucose concentrations (27.8-333.6mM). Because an understanding of metabolic regulations was required to provide guidance for further effective metabolic design or optimization, in this case, maximizing hydrogen production, carbon and energy balances by C. tyrobutyricum JM1 were determined and applied in anaerobic glucose metabolism. The overall carbon distribution suggested that initial glucose concentrations had strong influence on the stoichiometric coefficients of products and the molar production of ATP on the formation of biomass. C. tyrobutyricum JM1 had a high capacity for hydrogen production at the initial glucose concentration of 222.4 mM with high concentrations of acetate and butyrate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.9-12
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• 2005

Molecular characteristics and rheological properties of cellulose acetate butyrate (CAB), cellulose acetate propionate (CAP) and nitrocellulose (GC-519) which are being widely used as propellants were investigated. Their weight-average molecular weight (Mw) and number-average molecular weight (Mn) were estimated via Gel Permeartion Chromatograpy (GPC). Cellulose derivatices were mixed with di-n-propyl adipate (DNPA) which acted as plasticizer in acetone, and then rheological properties of the mixture of cellulose derivatives and this plasticizer in acetone were investigated at $0^{\circ}C$ by rheometer.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1215-1221
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• 1999

Twelve rumen fistulated cross-bred calves were divided into three groups and fed wheat straw and concentrate mixture according to their maintenance requirement. Animals in group II and III were fed 50 and 100mg rumensin per day, in addition to basal feed. Supplementation of rumensin in the diet decreased the dry matter intake significantly (p<0.05) along with a significant decrease in the straw intake. Digestibility coefficients of all the nutrients were not affected significantly except that of CF digestibility which was lower (p<0.05) in groups II and III as compared to group I. Among N-parameters in the rumen fluid, mean $NH_3-N$ was significantly lower in groups II and III (19.13 and 18.63 mg N/100 ml respectively) than in group I (22.68); total-N and TCA-ppt-N did not differ among the three groups. Total VFA concentration did also not differ among the three groups, however, propionate increased from 24.33 molar % to 32.73 while acetate and butyrate decreased respectively from 65.85 to 58.81% and 9.79 to 8.46%. Total VFA, bacteria and protozoa production rates were not affected significantly due to rumensin in diet. Methane production per kg DDM as well as % of methane in total gas were reduced at both the levels of rumensin on different concentrate ratios with wheat straw as roughage. Similar trend was also observed with rice straw and concentrate mixture as substrate with rumensin addition.