We have been studying the function and structure of fatty acid-containing extracellular polysaccharides (FACEPS) produced by bacteria belonging to the genus Rhodococcus. In this study, we examined the relationships be...We have been studying the function and structure of fatty acid-containing extracellular polysaccharides (FACEPS) produced by bacteria belonging to the genus Rhodococcus. In this study, we examined the relationships between the structure and emulsifying, thickening, moisture-absorption, and moisture-retention capabilities of rhodococcal FACEPS using S-2 EPS produced by R. rhodochrous strain S-2. We prepared chemically deacylated S-2 EPS (DeAcyl S-2 EPS) and palmitoylated DeAcyl S-2 EPS (ReAcyl S-2 EPS), and compared them with native S-2 EPS. All of the properties were attenuated and recovered by deacylation and reacylation of S-2 EPS, respectively. These results suggest that the fatty acid moiety of rhodococcal FACEPS is involved in such functional properties. We also showed that palmitoylation improved the emulsifying, moisture-ab-sorption, and moisture-retention abilities of other acidic polysaccharides that are commercially available. These results suggest that the acidity of the polysaccharide backbone is at least partly responsible for the observed functionality of fatty acid-containing polysaccharides. To our knowledge, this is the first report on multifunctional property of an anionic polymer incorporating low amounts of hydrophobic residues. The present findings could be useful for the creation of new multifunctional surfactants from renewable raw materials for use in various industries, e.g., in cosmetics.展开更多
In the accompanying paper (Part 1), we showed that the fatty acid moiety and the acidity of the polysaccharide-backbone of a fatty acid-containing polysaccharide might be involved in its emul-sification, moisture abso...In the accompanying paper (Part 1), we showed that the fatty acid moiety and the acidity of the polysaccharide-backbone of a fatty acid-containing polysaccharide might be involved in its emul-sification, moisture absorption, and moisture retention abilities. In this study, we synthesized alkyl esterified poly-γ-glutamic acid (PGA) with various chain lengths and degrees of substitution of the alkyl moieties to examine how hydrophobic groups incorporated in the anionic polymer contribute to enhanced emulsification, moisture absorption, and moisture retention. With a low degree of alkylation of PGA, these abilities were drastically improved. To improve the moisture absorption of PGA, alkylation with a short chain length is effective in forming interspaces between PGA chains to trap water molecules. Hydrophobic-hydrophilic balance may also be important to improve the emulsification and moisture retention abilities of PGA alkylates. To the best of our knowledge, this is the first report of the relationship between the structure and the multifunctional abilities of an anionic polymer incorporated with a small amount of hydrophobic residue. PGA alkylates, as well as fatty acid-containing polysaccharides, have potential use as multifunctional surfactants throughout various industries.展开更多
Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment.Nevertheless,the intricated,hydrophobic pores and groups weaken its water-holdin...Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment.Nevertheless,the intricated,hydrophobic pores and groups weaken its water-holding capacity in dry,sandy soils in arid lands.In order to combat this issue,starch-carbon-based material(SB),sodium alginate-carbon-based material(SAB),and chitosan-carbon-based material(CB)have been successfully synthesized through the graft-polymerization of biochar(BC).A series of soil column simulations were used to scrutinize the microstructure of the carbon-based material and explore its water absorption properties and its effects on sandy soil water infiltration,water retention,and aggregation.The results indicated that SB,SAB,and CB achieved water maximum absorption rates of 155,188,and 172 g g^(−1),respectively.Considering their impact on sandy soils,SB,SAB,and CB lengthened infiltration times by 1920,3330,and 3880 min,respectively,whilst enhancing the water retention capabilities of the soil by 18%,25%,and 23%in comparison to solely adding BC.The utilization of these innovative materials notably encouraged the formation of sandy soil aggregates ranging from 2.0 to 0.25 mm,endowing the aggregates with enhanced structural stability.Findings from potting experiments suggested that all three carbonbased materials were conducive to the growth of soybean seeds.Thus,it is evident that the carbon-based materials have been fabricated with success,and they have great potential not only to significantly augment the water retention capacities and structural robustness of sandy soils in arid areas,but also to bolster the development of soil aggregates and crop growth.These materials possess significant application potential for enhancing the quality of sandy soils in arid and semi-arid regions.展开更多
The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to d...The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to different stand types,we evaluated soil characteristics in twenty-one groups of EPs,Pinus massoniana Lamb.plantations（PMPs） and natural broadleaved forests（NBFs）across Guangdong Province,China.Both the physical characteristics of soil hydrology and the properties of soil nutrients in A and B horizons were determined.Results showed that,compared to NBFs,EPs and PMPs produced a shallower litter layer,reduced canopy density,higher soil bulk density,significantly lower total porosity,non-capillary porosity,total water volume,and hygroscopic water in the A horizon（P〈0.05）.Moreover,total N,available K,and soil organic carbon（SOC） in EPs and PMPs were significantly lower than in NBFs.EPs and PMPs did not differ significantly in N,P or K content,but PMPs had significantly lower SOC and boron in the A horizon than EPs.Low p H and poor capacity to buffer acidification generally occurred in all cover types.Both EPs and PMPs showed a decline in soil properties relative to NBFs,but EPs and PMPs exhibited no significant difference.These results indicate that actions are needed to ameliorate the potential negative effects on soil quality in forestry plantations.展开更多
文摘We have been studying the function and structure of fatty acid-containing extracellular polysaccharides (FACEPS) produced by bacteria belonging to the genus Rhodococcus. In this study, we examined the relationships between the structure and emulsifying, thickening, moisture-absorption, and moisture-retention capabilities of rhodococcal FACEPS using S-2 EPS produced by R. rhodochrous strain S-2. We prepared chemically deacylated S-2 EPS (DeAcyl S-2 EPS) and palmitoylated DeAcyl S-2 EPS (ReAcyl S-2 EPS), and compared them with native S-2 EPS. All of the properties were attenuated and recovered by deacylation and reacylation of S-2 EPS, respectively. These results suggest that the fatty acid moiety of rhodococcal FACEPS is involved in such functional properties. We also showed that palmitoylation improved the emulsifying, moisture-ab-sorption, and moisture-retention abilities of other acidic polysaccharides that are commercially available. These results suggest that the acidity of the polysaccharide backbone is at least partly responsible for the observed functionality of fatty acid-containing polysaccharides. To our knowledge, this is the first report on multifunctional property of an anionic polymer incorporating low amounts of hydrophobic residues. The present findings could be useful for the creation of new multifunctional surfactants from renewable raw materials for use in various industries, e.g., in cosmetics.
文摘In the accompanying paper (Part 1), we showed that the fatty acid moiety and the acidity of the polysaccharide-backbone of a fatty acid-containing polysaccharide might be involved in its emul-sification, moisture absorption, and moisture retention abilities. In this study, we synthesized alkyl esterified poly-γ-glutamic acid (PGA) with various chain lengths and degrees of substitution of the alkyl moieties to examine how hydrophobic groups incorporated in the anionic polymer contribute to enhanced emulsification, moisture absorption, and moisture retention. With a low degree of alkylation of PGA, these abilities were drastically improved. To improve the moisture absorption of PGA, alkylation with a short chain length is effective in forming interspaces between PGA chains to trap water molecules. Hydrophobic-hydrophilic balance may also be important to improve the emulsification and moisture retention abilities of PGA alkylates. To the best of our knowledge, this is the first report of the relationship between the structure and the multifunctional abilities of an anionic polymer incorporated with a small amount of hydrophobic residue. PGA alkylates, as well as fatty acid-containing polysaccharides, have potential use as multifunctional surfactants throughout various industries.
基金Bingtuan Science and Technology Program(2021DB019,2022CB001-01,2022CB001-07)National Natural Science Foundation of China(42275014).
文摘Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment.Nevertheless,the intricated,hydrophobic pores and groups weaken its water-holding capacity in dry,sandy soils in arid lands.In order to combat this issue,starch-carbon-based material(SB),sodium alginate-carbon-based material(SAB),and chitosan-carbon-based material(CB)have been successfully synthesized through the graft-polymerization of biochar(BC).A series of soil column simulations were used to scrutinize the microstructure of the carbon-based material and explore its water absorption properties and its effects on sandy soil water infiltration,water retention,and aggregation.The results indicated that SB,SAB,and CB achieved water maximum absorption rates of 155,188,and 172 g g^(−1),respectively.Considering their impact on sandy soils,SB,SAB,and CB lengthened infiltration times by 1920,3330,and 3880 min,respectively,whilst enhancing the water retention capabilities of the soil by 18%,25%,and 23%in comparison to solely adding BC.The utilization of these innovative materials notably encouraged the formation of sandy soil aggregates ranging from 2.0 to 0.25 mm,endowing the aggregates with enhanced structural stability.Findings from potting experiments suggested that all three carbonbased materials were conducive to the growth of soybean seeds.Thus,it is evident that the carbon-based materials have been fabricated with success,and they have great potential not only to significantly augment the water retention capacities and structural robustness of sandy soils in arid areas,but also to bolster the development of soil aggregates and crop growth.These materials possess significant application potential for enhancing the quality of sandy soils in arid and semi-arid regions.
基金supported by the Science and Technology Department of Guangdong Province,China(Nos.2015B020207002 and 2014A020216032)the National Natural Science Foundation of China(No.31270675)
文摘The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to different stand types,we evaluated soil characteristics in twenty-one groups of EPs,Pinus massoniana Lamb.plantations（PMPs） and natural broadleaved forests（NBFs）across Guangdong Province,China.Both the physical characteristics of soil hydrology and the properties of soil nutrients in A and B horizons were determined.Results showed that,compared to NBFs,EPs and PMPs produced a shallower litter layer,reduced canopy density,higher soil bulk density,significantly lower total porosity,non-capillary porosity,total water volume,and hygroscopic water in the A horizon（P〈0.05）.Moreover,total N,available K,and soil organic carbon（SOC） in EPs and PMPs were significantly lower than in NBFs.EPs and PMPs did not differ significantly in N,P or K content,but PMPs had significantly lower SOC and boron in the A horizon than EPs.Low p H and poor capacity to buffer acidification generally occurred in all cover types.Both EPs and PMPs showed a decline in soil properties relative to NBFs,but EPs and PMPs exhibited no significant difference.These results indicate that actions are needed to ameliorate the potential negative effects on soil quality in forestry plantations.
