Coriolus versicolor has been reported to have biological activities such as anticancer, antibacterial, antibiotics and immunopotentiation. The authors tried to ferment using lactobacilli associated with various biolog...Coriolus versicolor has been reported to have biological activities such as anticancer, antibacterial, antibiotics and immunopotentiation. The authors tried to ferment using lactobacilli associated with various biological functions and expected that fermented extract by lactobacilli will be superior to non-fermented extract in antioxidant activity. C. versicolor was extracted with 70% ethanol and then it was fermented by Lactobacillus acidophilus KCTC3164 and Lactobacillus plantarum KCTC3099, respectively. 1,l-dipheny｜-2-picrylhydrazyl （DPPH） scavenging activity, superoxide dismutase （SOD）-like activity and tetrazolium salt 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assays were performed. DPPH scavenging activity of fermented extract by L. acidophilus was higher than fermented extract by L. plantarum and antioxidant effect of fermented extract was 20%-30% higher than non-fermented extract. SOD-like activity was represented 18% in fermented extract by L. acidophilus, and was 27% in fermented extract by L. plantarum higher than non-fermented extract. As a result, this study suggests that it may need an efficient protocol for dominant bio-physiological activities such as extract volume or appropriate working volume of cultured cell or mixture condition. The fermented C. versicolor extract should provide with useful antioxidant agent in the human skin.展开更多
The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humi...The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humidity and temperature. About 5-10% of food production is spoiled by the growth of yeast and fungi in food materials. Similarly, in Western Europe, the growth of the spoilage fungi of bread is estimated to reach more than 200 million Euros per year. The history conditions of the food can be a major factor in determining any fungal spoilage--for example, stored and processed foods are more sensitive to spoilage when compared with fresh and prepared foods. Lactic acid bacteria isolated from Bulgarian wheat and rye flour were used in the present study to check their antifungal properties against pathogenic yeast and fungi imperfecta using standard disc diffusion method in vitro. A broad spectrum of antifungal activity of the six newly identified as L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6 was estimated. Our in vitro studies were performed with wheat and rye sourdough, in order to simulate a real product and to assess the bio-protective potential of the tested lactobacilli. The used test-cultures are representatives of carcinogenic, toxigenic, deteriorative and allergenic fungi from the genera .4spergillus and Penicillium. The all tested strains completely suppress the growth of against C. glabrata 72. Strains L. plantarum Tsl and Ts3 completely suppress the growth against S. cerevisae. While, in the sample with L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6, a retarded and weak growth of A. niger and P. claviforme was observed. However, the spore germination and the colony growth started only on the fifth day of the mould lactobacilli co-cultivation, which also should be considered as a good result. In this study six isolates Tsl,Ts2, Ts3, Ts4, Ts5 and Ts6, from the traditional Bulgarian wheat and rye flour have been identified as L. plantarum and L. helveticus and characterized as cultures with promising antifungal activity. Obtained results from the combined molecular identification （16S rRNA gene sequencing） approach contribute to give new data on the microbial biodiversity of this not well-studied niche. The antifungal activity of our new isolates, identified as L. plantarum and L. helveticus, seems to be a promising advantage of these six strains, suggesting their potential applications in different food technologies. However, more experiments have to be conducted to clarify the nature and the mechanisms of the reported antifungal activity and they are still in progress. The combination of dairy origin and strong inhibitory activity of the lactobacillus strains is a prerequisite for their possible application as starters and/or bioprotective antifungal adjuncts.展开更多
The lactic acid bacteria are used in fermentation and the bio conservation of food, because it produces organic acids and other antibacterial substances as the bacteriocin to inhibit certain pathogenic stocks. In orde...The lactic acid bacteria are used in fermentation and the bio conservation of food, because it produces organic acids and other antibacterial substances as the bacteriocin to inhibit certain pathogenic stocks. In order to demonstrate the inhibitory effect of these bacteria, we studied the antagonistic capacity of the two leavens of yoghourt （Streptococcus thermophilus and Lactobacillus bulgaricus） and Bifidobacterium bifidum with respect to Helicobacterpylori by the method of diffusion by discs. Their interactions led to the emergence of large zones of inhibition. Bifidobacterium bifidum led the greatest halo with a diameter of 0.8 cm by contribution to Lactobacillus bulgaricus （0.5 cm） and Streptococcus thermophilus （0.3 cm）. The additional tests were required to know the exact nature of the inhibitors. The results showed that the antibacterial peptides （bacteriocins） have a narrow spectrum of activity against the species pathogen compared to that caused by acidity.展开更多
The improvement of propionic acid production for antifungal activity, as fermenting by calcium alginate immobilized cells of Propionibacterium acidipropionici TISTR 442 was investigated by using whey as substrate. Opt...The improvement of propionic acid production for antifungal activity, as fermenting by calcium alginate immobilized cells of Propionibacterium acidipropionici TISTR 442 was investigated by using whey as substrate. Optimal condition for immobilization was performed by adjusting tube distance to CaCI2 solution to be 4-6 cm and 7 mL/min flow rate of alginate gel. The production of propionic acid by immobilized cells in a 2 L fermentor using 1% CaCO3 and 5 N KOH to control the pH at 6.5 gave maximum propionic acid and they had consistent potential to recycle 2 rounds of fermentation and produced the total of 29.24 g/L propionic acid （15.85 ± 0.25 g/L and 13.39 ± 0.25 g/L propionic acid from Batch 1 and Batch 2 fermentation, respectively）. Compared to free-cell fermentation, propionic acid productivity increased 20% （0.083 g/h vs. 0.070 g/h） and fermentation time reduced 11% （192 h vs. 216 h） in 2 L fermentor with 40 g/L initial total sugar from whey. The fermented propionic acid as well as the commercial propionic acid from chemical process was able to inhibit the growth of the fungal tested.展开更多
Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLL...Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLLA ternary blend,which was prepared by dynamic vulcanization of PLLA with poly（D-lactide）（PDLA） and an unsaturated bioelastomer（UBE）. The results indicated that during dynamic vulcanization PDLA cocrystallized with PLLA to form stereocomplex（SC） crystallites,which not only enhanced the molecular entanglement but also accelerated the crystallization rate of PLLA matrix. With increase in the content of PDLA,the matrix molecular entanglement increased while phase-separation was enhanced,which enabled the impact strength to increase first and then decrease. The ternary blends containing 10 wt.% PDLA showed the highest impact strength. The presence of SC crystallites makes it possible to achieve a fully sustainable PLLA/VUB/PDLA ternary blend with highly crystalline matrix under conventional injection molding,due to the high nucleation efficiency of SC towards crystallization of PLLA. The highly crystalline ternary blend showed excellent heat resistance and better impact toughness than high impact polystyrene.展开更多
文摘Coriolus versicolor has been reported to have biological activities such as anticancer, antibacterial, antibiotics and immunopotentiation. The authors tried to ferment using lactobacilli associated with various biological functions and expected that fermented extract by lactobacilli will be superior to non-fermented extract in antioxidant activity. C. versicolor was extracted with 70% ethanol and then it was fermented by Lactobacillus acidophilus KCTC3164 and Lactobacillus plantarum KCTC3099, respectively. 1,l-dipheny｜-2-picrylhydrazyl （DPPH） scavenging activity, superoxide dismutase （SOD）-like activity and tetrazolium salt 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assays were performed. DPPH scavenging activity of fermented extract by L. acidophilus was higher than fermented extract by L. plantarum and antioxidant effect of fermented extract was 20%-30% higher than non-fermented extract. SOD-like activity was represented 18% in fermented extract by L. acidophilus, and was 27% in fermented extract by L. plantarum higher than non-fermented extract. As a result, this study suggests that it may need an efficient protocol for dominant bio-physiological activities such as extract volume or appropriate working volume of cultured cell or mixture condition. The fermented C. versicolor extract should provide with useful antioxidant agent in the human skin.
文摘The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humidity and temperature. About 5-10% of food production is spoiled by the growth of yeast and fungi in food materials. Similarly, in Western Europe, the growth of the spoilage fungi of bread is estimated to reach more than 200 million Euros per year. The history conditions of the food can be a major factor in determining any fungal spoilage--for example, stored and processed foods are more sensitive to spoilage when compared with fresh and prepared foods. Lactic acid bacteria isolated from Bulgarian wheat and rye flour were used in the present study to check their antifungal properties against pathogenic yeast and fungi imperfecta using standard disc diffusion method in vitro. A broad spectrum of antifungal activity of the six newly identified as L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6 was estimated. Our in vitro studies were performed with wheat and rye sourdough, in order to simulate a real product and to assess the bio-protective potential of the tested lactobacilli. The used test-cultures are representatives of carcinogenic, toxigenic, deteriorative and allergenic fungi from the genera .4spergillus and Penicillium. The all tested strains completely suppress the growth of against C. glabrata 72. Strains L. plantarum Tsl and Ts3 completely suppress the growth against S. cerevisae. While, in the sample with L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6, a retarded and weak growth of A. niger and P. claviforme was observed. However, the spore germination and the colony growth started only on the fifth day of the mould lactobacilli co-cultivation, which also should be considered as a good result. In this study six isolates Tsl,Ts2, Ts3, Ts4, Ts5 and Ts6, from the traditional Bulgarian wheat and rye flour have been identified as L. plantarum and L. helveticus and characterized as cultures with promising antifungal activity. Obtained results from the combined molecular identification （16S rRNA gene sequencing） approach contribute to give new data on the microbial biodiversity of this not well-studied niche. The antifungal activity of our new isolates, identified as L. plantarum and L. helveticus, seems to be a promising advantage of these six strains, suggesting their potential applications in different food technologies. However, more experiments have to be conducted to clarify the nature and the mechanisms of the reported antifungal activity and they are still in progress. The combination of dairy origin and strong inhibitory activity of the lactobacillus strains is a prerequisite for their possible application as starters and/or bioprotective antifungal adjuncts.
文摘The lactic acid bacteria are used in fermentation and the bio conservation of food, because it produces organic acids and other antibacterial substances as the bacteriocin to inhibit certain pathogenic stocks. In order to demonstrate the inhibitory effect of these bacteria, we studied the antagonistic capacity of the two leavens of yoghourt （Streptococcus thermophilus and Lactobacillus bulgaricus） and Bifidobacterium bifidum with respect to Helicobacterpylori by the method of diffusion by discs. Their interactions led to the emergence of large zones of inhibition. Bifidobacterium bifidum led the greatest halo with a diameter of 0.8 cm by contribution to Lactobacillus bulgaricus （0.5 cm） and Streptococcus thermophilus （0.3 cm）. The additional tests were required to know the exact nature of the inhibitors. The results showed that the antibacterial peptides （bacteriocins） have a narrow spectrum of activity against the species pathogen compared to that caused by acidity.
文摘The improvement of propionic acid production for antifungal activity, as fermenting by calcium alginate immobilized cells of Propionibacterium acidipropionici TISTR 442 was investigated by using whey as substrate. Optimal condition for immobilization was performed by adjusting tube distance to CaCI2 solution to be 4-6 cm and 7 mL/min flow rate of alginate gel. The production of propionic acid by immobilized cells in a 2 L fermentor using 1% CaCO3 and 5 N KOH to control the pH at 6.5 gave maximum propionic acid and they had consistent potential to recycle 2 rounds of fermentation and produced the total of 29.24 g/L propionic acid （15.85 ± 0.25 g/L and 13.39 ± 0.25 g/L propionic acid from Batch 1 and Batch 2 fermentation, respectively）. Compared to free-cell fermentation, propionic acid productivity increased 20% （0.083 g/h vs. 0.070 g/h） and fermentation time reduced 11% （192 h vs. 216 h） in 2 L fermentor with 40 g/L initial total sugar from whey. The fermented propionic acid as well as the commercial propionic acid from chemical process was able to inhibit the growth of the fungal tested.
基金supported by the National Science Foundation of China (51673158)the Opening Project of Key Laboratory of Polymer Processing Engineering (South China University of Technology),Ministry of Education (KFKT02)the Fundamental Research Funds for the Central Universities (XDJK2017A016 and XDJK2017C022)
文摘Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLLA ternary blend,which was prepared by dynamic vulcanization of PLLA with poly（D-lactide）（PDLA） and an unsaturated bioelastomer（UBE）. The results indicated that during dynamic vulcanization PDLA cocrystallized with PLLA to form stereocomplex（SC） crystallites,which not only enhanced the molecular entanglement but also accelerated the crystallization rate of PLLA matrix. With increase in the content of PDLA,the matrix molecular entanglement increased while phase-separation was enhanced,which enabled the impact strength to increase first and then decrease. The ternary blends containing 10 wt.% PDLA showed the highest impact strength. The presence of SC crystallites makes it possible to achieve a fully sustainable PLLA/VUB/PDLA ternary blend with highly crystalline matrix under conventional injection molding,due to the high nucleation efficiency of SC towards crystallization of PLLA. The highly crystalline ternary blend showed excellent heat resistance and better impact toughness than high impact polystyrene.
