In this study,the pectin of waste seed melon peel in Xinjiang was used as raw material to prepare seed melon pectin oligosaccharide(Sm-POS).The separation and purification of Sm-POS were carried out by HPD-750 macropo...In this study,the pectin of waste seed melon peel in Xinjiang was used as raw material to prepare seed melon pectin oligosaccharide(Sm-POS).The separation and purification of Sm-POS were carried out by HPD-750 macroporous resin chromatography column and gel chromatography to further study the molecular structure of its active component with antibacterial effect by FT-IR,NMR,and LC/MS.The antibacterial activity and mechanism of the Sm-POS active component were investigated by inhibition zone experiment,minimum inhibitory concentration determination,cell growth curve determination,scanning electron microscopy,and flow cytometry analysis.Results showed that Sm-POS-2 was an oligosaccharide composed of two galacturonic acids,one glucose,one arabinose,and one xylose.It showed good antibacterial activity and suppressed the growth of E.coli and S.aureus at minimum inhibitory concentrations(MIC)of 25.0 and 50.0 g/L,respectively.The inhibitory effect of Sm-POS on E.coli and S.aureus was mainly due to cell membrane contraction or rupture,leading to the apoptosis or necrosis of bacterial cells.展开更多
In the present research work, a non-edible oil source Cucumis melo var. agrestis （wild melon） was systematically identified and studied for biodiesel production and its characterization. The extracted oil was 29.1% ...In the present research work, a non-edible oil source Cucumis melo var. agrestis （wild melon） was systematically identified and studied for biodiesel production and its characterization. The extracted oil was 29.1% of total dry seed weight. The free fatty acid value of the oil was found to be 0.64%, and the single-step alkaline transesterification method was used for conversion of fatty acids into their respective methyl esters. The maximum conversion efficiency of fatty acids was obtained at 0.4 wt% NaOH （used as catalyst）, 30% （methanol to oil, v/v） methanol amount, 60 ℃ reaction temperature, 600-rpm agitation rate and 60-min reaction time. Under these optimal conditions, the conversion efficiency of fatty acid was 92%. However, in the case of KOH as catalyst, the highest conversion （85%） of fatty acids was obtained at 40% methanol to oil ratio, 1.28 wt% KOH, 60 ℃ reaction temperature, 600-rpm agitation rate and 45 min of reaction time. Qualitatively, biodiesel was characterized through Fourier transform infrared spectroscopy （FFIR） and gas chromatography and mass spectroscopy （GC-MS）. FTIR results demonstrated a strong peak at 1742 cm-1, showing carbonyl groups （C=O） of methyl esters. However, GC-MS results showed the presence of twelve methyl esters comprised of lauric acid, myristic acid, palmitic acid, non-decanoic acid, hexadecanoic acid, octadecadienoic acid and octadecynoic acid. The fuel properties were found to fall within the range recommended by the international biodiesel standard, i.e., American Society of Testing Materials （ASTM）： flash point of 91℃, density of 0.873 kg/L, viscosity of 5.35 cSt, pour point of - 13 ℃, cloud point of -10 ℃, total acid number of 0.242 mg KOH/g and sulfur content of 0.0043 wt%. The present work concluded the potential of wild melon seed oil as excellent non-edible source of bioenergy.展开更多
文摘In this study,the pectin of waste seed melon peel in Xinjiang was used as raw material to prepare seed melon pectin oligosaccharide(Sm-POS).The separation and purification of Sm-POS were carried out by HPD-750 macroporous resin chromatography column and gel chromatography to further study the molecular structure of its active component with antibacterial effect by FT-IR,NMR,and LC/MS.The antibacterial activity and mechanism of the Sm-POS active component were investigated by inhibition zone experiment,minimum inhibitory concentration determination,cell growth curve determination,scanning electron microscopy,and flow cytometry analysis.Results showed that Sm-POS-2 was an oligosaccharide composed of two galacturonic acids,one glucose,one arabinose,and one xylose.It showed good antibacterial activity and suppressed the growth of E.coli and S.aureus at minimum inhibitory concentrations(MIC)of 25.0 and 50.0 g/L,respectively.The inhibitory effect of Sm-POS on E.coli and S.aureus was mainly due to cell membrane contraction or rupture,leading to the apoptosis or necrosis of bacterial cells.
文摘In the present research work, a non-edible oil source Cucumis melo var. agrestis （wild melon） was systematically identified and studied for biodiesel production and its characterization. The extracted oil was 29.1% of total dry seed weight. The free fatty acid value of the oil was found to be 0.64%, and the single-step alkaline transesterification method was used for conversion of fatty acids into their respective methyl esters. The maximum conversion efficiency of fatty acids was obtained at 0.4 wt% NaOH （used as catalyst）, 30% （methanol to oil, v/v） methanol amount, 60 ℃ reaction temperature, 600-rpm agitation rate and 60-min reaction time. Under these optimal conditions, the conversion efficiency of fatty acid was 92%. However, in the case of KOH as catalyst, the highest conversion （85%） of fatty acids was obtained at 40% methanol to oil ratio, 1.28 wt% KOH, 60 ℃ reaction temperature, 600-rpm agitation rate and 45 min of reaction time. Qualitatively, biodiesel was characterized through Fourier transform infrared spectroscopy （FFIR） and gas chromatography and mass spectroscopy （GC-MS）. FTIR results demonstrated a strong peak at 1742 cm-1, showing carbonyl groups （C=O） of methyl esters. However, GC-MS results showed the presence of twelve methyl esters comprised of lauric acid, myristic acid, palmitic acid, non-decanoic acid, hexadecanoic acid, octadecadienoic acid and octadecynoic acid. The fuel properties were found to fall within the range recommended by the international biodiesel standard, i.e., American Society of Testing Materials （ASTM）： flash point of 91℃, density of 0.873 kg/L, viscosity of 5.35 cSt, pour point of - 13 ℃, cloud point of -10 ℃, total acid number of 0.242 mg KOH/g and sulfur content of 0.0043 wt%. The present work concluded the potential of wild melon seed oil as excellent non-edible source of bioenergy.
