pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, bat...pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value （pH 5-9） with or without acetate （20 g/L）. The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence ofpH 7〉pH 8〉pH 9〉pH 6〉pH 5; but the inhibition of acetate （20 g/L） was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors （pH and acetate） and the response variables was evaluated by partial least square modeling （PLS）. The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.展开更多
Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two...Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two rapeseed germplasms YH25005 and R8Q10 with high content(up to 21%)ALA were developed by intervarietal crossing.They were used as the maternal parent(P_(1))when crossed with a low ALA parent SW(P2)to produce the seeds of the F1 hybrid,F2,and backcrosses to P1(BCP1)and P2(BCP2).A multigeneration joint segregation analysis was conducted to determine major gene t polygene effects of the content of three major unsaturated fatty acids including oleic(OA),linoleic(LA)and ALA.The results showed that,although some genes favorable to ALA accumulation were not allelic in R8Q10 and YH25005,all the inheritances of OA,LA and ALA in YH25005×SW and R8Q10×SW followed a genetic model of‘two pairs of additive major genes t additive-dominant polygenes’.It is suggested that the contents of OA,LA and ALA are closely related and the major genes in the parent SW containing loss-of-function mutations in FAD2 and FAD3 loci had strong effect to reduce ALA and elevate OA.However,total genetic effect of the polygenes was greater than that of the two major genes,especial on ALA content.It indicated that it is necessary to employ a larger F2 population to find the plant that accumulate enough minor-effect polygenes for high ALA content.The results are useful for high ALA rapeseed breeding and future work of gene mapping.展开更多
The utilization of waste feedstocks rich in free fatty acids(FFAs)improves biofuel production on the basis of economics and sustainability.However,converting these feedstocks to usable biofuel poses inherent problems ...The utilization of waste feedstocks rich in free fatty acids(FFAs)improves biofuel production on the basis of economics and sustainability.However,converting these feedstocks to usable biofuel poses inherent problems in terms of the FFA to biofuel conversion yield and the catalyst lifetime.Here,we report novel ferric sulfate impregnated carbon derived from waste tires as highly active catalysts for FFA to biofuel conversion.Our approach takes advantage of facile synthesis methods involving sonication and dehydration processes to create materials that are useful for the efficient catalytic conversion of FFAs to advanced biofuels.Esterification of FFAs to fatty acid methyl esters was achieved at 65C and atmospheric pressure with>98%yield even in the presence of triglycerides.These catalysts maintained similar activity after four successive uses,which indicates that the active catalytic sites are effectively supported by the three-dimensional meso/microporous architecture of the tire-derived carbon.展开更多
Milk fatty acids significantly contribute to human nutrition and clinical health.However,previous evidence for changes in the fatty acid profiles of different dairy species following homogenization and heat treatment ...Milk fatty acids significantly contribute to human nutrition and clinical health.However,previous evidence for changes in the fatty acid profiles of different dairy species following homogenization and heat treatment is lacking.Here,changes in fat globule particle size and fatty acids in samples of Holstein,goat,buffalo,yak,and camel milk following homogenization(20 MPa)and heat treatment(63℃for 30 min and 90℃for 15 min)were investigated using a laser particle sizer and gas chromatography approach.The results indicated that the milk fat globule particle size of all studied dairy species significantly decreased after homogenization and heat treatment,in which there was no difference.The fatty acid composition of C10:0 and medium-chain fatty acid in goat milk,Ci8:0 and long-chain fatty acid in camel milk,and C16:0 in buffalo and yak milk served as the characteristic traits of these milks.Changes in the relative contents of several fatty acids(C4:0,C10:0,C16:0,C18:0,C18:1n9c,and C18:3n3)were dependent on homogenization,heat treatment,and the type of dairy species.In particular,C18:3n3 significantly decreased in goat and camel milk after homogenization and heat treatment.These findings provide new insights into how homogenization and heat treatment affect the fatty acid profile and can be used to further improve the heat treatment of milk from minor dairy species.展开更多
文摘pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value （pH 5-9） with or without acetate （20 g/L）. The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence ofpH 7〉pH 8〉pH 9〉pH 6〉pH 5; but the inhibition of acetate （20 g/L） was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors （pH and acetate） and the response variables was evaluated by partial least square modeling （PLS）. The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.
基金supported by the project of Key R&D plans of Shaanxi Province(2021NY-074)Yangling Seed Industry Innovation Plan.
文摘Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two rapeseed germplasms YH25005 and R8Q10 with high content(up to 21%)ALA were developed by intervarietal crossing.They were used as the maternal parent(P_(1))when crossed with a low ALA parent SW(P2)to produce the seeds of the F1 hybrid,F2,and backcrosses to P1(BCP1)and P2(BCP2).A multigeneration joint segregation analysis was conducted to determine major gene t polygene effects of the content of three major unsaturated fatty acids including oleic(OA),linoleic(LA)and ALA.The results showed that,although some genes favorable to ALA accumulation were not allelic in R8Q10 and YH25005,all the inheritances of OA,LA and ALA in YH25005×SW and R8Q10×SW followed a genetic model of‘two pairs of additive major genes t additive-dominant polygenes’.It is suggested that the contents of OA,LA and ALA are closely related and the major genes in the parent SW containing loss-of-function mutations in FAD2 and FAD3 loci had strong effect to reduce ALA and elevate OA.However,total genetic effect of the polygenes was greater than that of the two major genes,especial on ALA content.It indicated that it is necessary to employ a larger F2 population to find the plant that accumulate enough minor-effect polygenes for high ALA content.The results are useful for high ALA rapeseed breeding and future work of gene mapping.
文摘The utilization of waste feedstocks rich in free fatty acids(FFAs)improves biofuel production on the basis of economics and sustainability.However,converting these feedstocks to usable biofuel poses inherent problems in terms of the FFA to biofuel conversion yield and the catalyst lifetime.Here,we report novel ferric sulfate impregnated carbon derived from waste tires as highly active catalysts for FFA to biofuel conversion.Our approach takes advantage of facile synthesis methods involving sonication and dehydration processes to create materials that are useful for the efficient catalytic conversion of FFAs to advanced biofuels.Esterification of FFAs to fatty acid methyl esters was achieved at 65C and atmospheric pressure with>98%yield even in the presence of triglycerides.These catalysts maintained similar activity after four successive uses,which indicates that the active catalytic sites are effectively supported by the three-dimensional meso/microporous architecture of the tire-derived carbon.
基金the High-level Talents Foundation of Qingdao Agricultural University(665/1120053)Shandong Provincial Science and Technology Foundation,China(YDZX2021111)Qingdao science and technology demonstration and guidance project(21-1-4-ny-17-nsh),China.
文摘Milk fatty acids significantly contribute to human nutrition and clinical health.However,previous evidence for changes in the fatty acid profiles of different dairy species following homogenization and heat treatment is lacking.Here,changes in fat globule particle size and fatty acids in samples of Holstein,goat,buffalo,yak,and camel milk following homogenization(20 MPa)and heat treatment(63℃for 30 min and 90℃for 15 min)were investigated using a laser particle sizer and gas chromatography approach.The results indicated that the milk fat globule particle size of all studied dairy species significantly decreased after homogenization and heat treatment,in which there was no difference.The fatty acid composition of C10:0 and medium-chain fatty acid in goat milk,Ci8:0 and long-chain fatty acid in camel milk,and C16:0 in buffalo and yak milk served as the characteristic traits of these milks.Changes in the relative contents of several fatty acids(C4:0,C10:0,C16:0,C18:0,C18:1n9c,and C18:3n3)were dependent on homogenization,heat treatment,and the type of dairy species.In particular,C18:3n3 significantly decreased in goat and camel milk after homogenization and heat treatment.These findings provide new insights into how homogenization and heat treatment affect the fatty acid profile and can be used to further improve the heat treatment of milk from minor dairy species.
