• Journal of Microbiology and Biotechnology
• /
• v.28 no.5
• /
• pp.739-747
• /
• 2018

The low solubility and high-cost recovery of Propionibacterium acnes polyunsaturated fatty acid isomerase (PAI) are key problems in the bioproduction of high value-added conjugated linoleic acid (CLA). To improve the solubility of recombinant PAI, six chaperone proteins were coexpressed with PAI. Introduction of GroELS proteins dramatically improved the PAI solubility from 29% to 97%, with increased activity by 57.8%. Combined expression of DnaKJ-GrpE and GroELS proteins increased the activity by 11.9%. In contrast, coexpression of DnaKJ-GrpE proteins significantly reduced the activity by 57.4%. Plasmids pTf16 harboring the tig gene and pG-Tf2 containing the tig and groEL-groES genes had no visible impact on PAI expression. The lytic protein E was then introduced into the recombinant Escherichia coli to develop a cell autolysis system. A 35% activity of total intracellular PAI was released from the cytoplasm by suspending the lysed cells in distilled water. The PAI recovery was further improved to 81% by optimizing the release conditions. The lipase from Rhizopus oryzae was also expressed in E. coli, with an extracellular activity of 110.9 U/ml. By using the free PAI and lipase as catalysts, a joint system was established for producing CLA from sunflower oil. Under the optimized conditions, the maximum titer of t-10,c-12-CLA reached 9.4 g/l. This work provides an effective and low-cost strategy to improve the solubility and recovery of the recombinant intracellular PAI for further large-scale production of CLA.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.5
• /
• pp.557-568
• /
• 1995

Proteolytic properties of enzymes from the muscle and viscera of anchovy have been examined. Cathepsin L, chymotrypsin, and trypsin showed similar Km values for casein. However, they had higher Km values for myofibrillar proteins than those for casein. The $k_cat$ of cathepsin L and chymotrypsin for myofibrillar proteins were higher than that of trypsin, and also cathepsin L and chymotrypsin caused higher hydrolysis in myofibrillar proteins of anchovy and yellowtail. In the presence of sodium chloride$(0-25\%)$, proteolytic activity for myofibrillar proteins from yellowtail was higher than that for casein. Proteolytic activity was decreased with the increase of sodium chloride concentration. Cathepsin L had been less affected by NaCl concentration and temperature on the hydrolysis of myofibrillar proteins than chymotrypsin and trypsin. Cathepsin L and chymotrypsin were move responsible to the autolysis of muscle proteins from fish than trypsin.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.9 no.5
• /
• pp.400-404
• /
• 2004

This Study was tarried out to investigate the relationship ACE inhibitory activity and degradations of sulfur containing materials in Dolsan leaf mustard juice (DLMJ). The changes of sulfur containing materials which were treated with autolysis, myrosinase, ascorbate and papain were studied, as well as the changes of ACE inhibitory activity in DLMJ. At $37^{\circ}C$, sulfur contain-ing materials by autolysis decreased most rapidly from $0.43\%$ to $0.13\%$ in the second day. Conversely. ACE inhibitory activity increased most from $66\%$ to $87\%$. in the second day at $37^{\circ}C$. As myrosinase concentrations increased more, sulfur containing materials in DLMJ decreased more. The ACE inhibitory activities at 0, 0.5, 1, 2, and 4 Units of myrosinase for 240 min later were 70, 74, 75, 82, and $85\%$, respectively. At 1 mM ascorbate. concentrations of Sulfur containing materials in DLMJ decreased more significantly on the second day than on the other days. At 1 mM ascorbate for 6 days, ACE Inhibitory activity reached a maximum of about $92\%$. And, an increase of papain concentration was noted in accordance with a decreased sulfur containing materials. The maximum rate of AEC inhibitory activity at control, 3, 6, and 12 Units of papains treatments was shown as 70, 70, 75, and $78\%$ at 60 min, respectively. These results suggested that the degradation of sulfur containing materials led to the increase of ACE inhibitory activity. Consequently, it was suggested that ACE inhibiting was significantly related to the degradatives of sulfur containing materials.

• Molecules and Cells
• /
• v.40 no.12
• /
• pp.935-944
• /
• 2017

More than 50% of sepsis cases are associated with pneumonia. Sepsis is caused by infiltration of bacteria into the blood via inflammation, which is triggered by the release of cell wall components following lysis. However, the regulatory mechanism of lysis during infection is not well defined. Mice were infected with Streptococcus pneumoniae D39 wild-type (WT) and lipase mutant (${\Delta}lipA$) intranasally (pneumonia model) or intraperitoneally (sepsis model), and survival rate and pneumococcal colonization were determined. LipA and autolysin (LytA) levels were determined by qPCR and western blotting. S. pneumoniae Spd_1447 in the D39 (type 2) strain was identified as a lipase (LipA). In the sepsis model, but not in the pneumonia model, mice infected with the ${\Delta}lipA$ displayed higher mortality rates than did the D39 WT-infected mice. Treatment of pneumococci with serum induced LipA expression at both the mRNA and protein levels. In the presence of serum, the ${\Delta}lipA$ displayed faster lysis rates and higher LytA expression than the WT, both in vitro and in vivo. These results indicate that a pneumococcal lipase (LipA) represses autolysis via inhibition of LytA in a sepsis model.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.2
• /
• pp.101-108
• /
• 2016

We investigated changes in the physiochemical quality of sailfin sandfish sauces fermented with two kojis during long-term storage at room temperature. Four fish sauces, including a control, were prepared by salt-fermentation with soybean koji (S-koji) or rice koji (R-koji) after autolysis. During storage, for 12 months, the color and levels of amino acids, total volatile base nitrogen (T-VBN) and organic acids but not moisture, salt or total nitrogen levels or pH differed markedly according to fish sauce type. The total nitrogen level was highest in S-koji, but there was no difference in the rate of increase in amino acid levels among the four fish sauces during storage. The T-VBN, of autolysis and S-koji were significantly higher than those of the control and R-koji during the entire storage period (P<0.05). The initial organic acid level did not differ among the four fish sauces, whereas it was notably higher in R-koji than in the other sauces at the end of storage. Hunter L, a and b values decreased in all fish sauces with increasing storage time. In conclusion, soybean koji may enhance the levels of nitrogen compounds as well as T-VBN in fish sauce, while rice koji reduced the formation of excess T-VBN and increased organic acid levels during storage at room temperature.

• The Korean Journal of Mycology
• /
• v.14 no.4
• /
• pp.273-280
• /
• 1986

The degree of autolysis and lytic enzyme production in the culture filtrate of Rhizopus oryzae was investigated. The formation of protoplast by using autolytic enzymes from Rh. oryzae was also attempted. Protoplasts were liberated from Rh. oryzae mycelium by lytic enzymes present in autolytic-phase culture filtrate. Maximum release of chitosanase and proteolytic enzyme into culture filtrate during autolysis was corresponded to maximum protoplast-liberating activity. High yields of protoplasts were obtained from 10 hr-age of Rh. oryzae mycelium with 0.5 M mannitol as osmotic stabilizer. The optimum temperature and pH for mycelium digestion were $25{\sim}30^{\circ}C$ and $6.0{\sim}6.5$ respectively. The mycelium of the 18 hours cultures were treated with autolytic enzyme in same volume of osmotic stabilizer at $30^{\circ}C$ for 5 hours and then it was confirmed by scanning electoron microscope that protoplast were produced beside the digesting cell wall of the fungi.

• KSBB Journal
• /
• v.24 no.5
• /
• pp.463-468
• /
• 2009

Selenium-containing peptide (Selenium peptide) was produced by autolysis of Saccharomyces cerevisiae which was cultured in inorganic selenium-supplemented medium. Selenium peptide showed antioxidant activity and protective effects on UVB irradiated human fibroblast. Minimal toxicity of selenium peptide was observed whereas selenium nitrate exhibited cell toxicity as low as $10^{-9}\;M$. Selenium peptide also increased human fibroblast growth, procollagen type I and also decreased MMP-1 (matrix metalloprotease-1). This result showed the potential of selenium peptide as a nontoxic antioxidant.

• Korean Journal of Food Science and Technology
• /
• v.16 no.1
• /
• pp.23-28
• /
• 1984

Anchovy homogenates with or without salt were autolyzed at various pH and temperature conditions. In the initial hydrolysis during 20 hours, the highest autolysis of anchovy homogenate was achieved at pH 4 and $50^{\circ}C$. However, the addition of 20% salt changed the optimum condition to pH 6 and $50^{\circ}C$. When the digestion time was prolonged to 8 days, the most favorable temperature for the autolysis of salted anchovy was lowered to $40^{\circ}C$ compared with $50^{\circ}C$ of initial hydrolysis while the optimum pH was unchanged. Under the best conditions described above, 60.5% of anchovy nitrogen was converted to TCA-soluble nitrogen in 20 hr-incubation without salting, but it was reduced to 49.8% with salting. In the 8 days hydrolysis of salted anchovy, as much as 83.1% of total nitrogen was transformed into TCA-soluble nitrogen. Slight increase in the degree of hydrolysis up to 89.6% was occurred during subsequent ripening period of 52 days at ambient temperature.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.15 no.3
• /
• pp.201-206
• /
• 1986

The purpose of this study is to prepare the fish sauce front mackerel scrap which usually comprises $40{\sim}50%$ of raw fish in processing. Mackerel scrap was chopped, mired with equal weight of water, and then hydrolyzed by autolysis. The optimal conditions for hydrolysis of .mackerel scrap were at $55^{\circ}C$ for 4 hours. The maximum hydrolyzed rate of protein was 65% by autolysis. Crude protein content (6.5%) and color of mackerel sauce were similar to those of traditional soybean sauce. The abundant amino acids in mackerel sauce were leucine (22.8%), isoleucine (15.0%), phenylalanine (12.6%) and valine (12.5%). In sensory evaluation, mackerel sauce was at least equal to the traditional soybean sauce in product quality.

• Animal Bioscience
• /
• v.35 no.9
• /
• pp.1400-1407
• /
• 2022

Objective: This research determined the chemical composition and the apparent and standardized ileal digestibility (AID and SID) of crude protein (CP) and amino acids (AA) in whole yeast and autolyzed yeast derived from sugarcane ethanol production fed to growing pigs. Methods: Six growing pigs were randomly allocated in a replicated 3×3 Latin square design with 3 diets and 3 periods of 7 days each, resulting in a total of 6 experimental replications. Three assay diets were formulated using whole yeast, autolyzed yeast, or soybean meal as the sole sources of dietary CP and AA. Pigs were allowed to adapt to the assay diets for 5 days. Thereafter, ileal digesta samples were collected continuously for 8 hours on days 6 and 7. Results: There was no difference in the chemical composition between whole yeast and autolyzed yeast, but whole yeast had low digestibility of CP and AA due to the presence of a rigid cell wall. As conducting autolysis can induce cell wall damage, the AID and SID of CP and AA were greater in autolyzed yeast than in whole yeast. Conclusion: The information obtained on the SID of CP and AA in both yeast products can be used for the accurate estimation of the bioavailability of CP and AA in feed formulations. The yeast products derived from sugarcane ethanol production are an alternative protein source in pig diets.