Biochemical, chemical, and mechanical, techniques have been employed to enhance soil resilience for decades. While the use of mechanical techniques requires transporting huge amounts of soil materials, the cement used...Biochemical, chemical, and mechanical, techniques have been employed to enhance soil resilience for decades. While the use of mechanical techniques requires transporting huge amounts of soil materials, the cement used in chemical techniques may lead to increase atmospheric carbon dioxide. Numerous studies indicate that biochemical techniques may be less expensive, cost effective, and environmentally friendly. Biopolymers and enzymes derived from microorganisms have been suggested as biological enhancers in strengthening and fortifying soils used for earthen structures. Lime and other treatment techniques used as biobased materials have been shown to be less effective for stabilizing soils. Here, we review biochemical processes and techniques involved in the interactions of soil enzymes, microorganisms, microbial extracellular polymeric substances, and other biopolymers with soil particles, and the challenges and strategies of their use as biobased materials for stabilizing soils. This review provides their impacts on various soil properties and the growth potentials of agricultural crops. .展开更多
Phosphatases are diverse groups of enzymes that deserve special attention because of their significant roles in organic phosphorus (OP) mineralization to inorganic available forms (Pi). This work 1) compared the catal...Phosphatases are diverse groups of enzymes that deserve special attention because of their significant roles in organic phosphorus (OP) mineralization to inorganic available forms (Pi). This work 1) compared the catalytic potentials of commercially acid phosphatase from wheat germ, sweet potato, and potato, and alkaline phosphatase from E. coli;2) demonstrated that the rate of hydrolysis, catalytic efficiency, thermal stability, and optimal pH of these enzymes depended on enzyme sources and the stereochemical or stereoisomeric structures of the substrates;3) revealed that both acid and alkaline phosphatases exhibited broad range of substrate hydrolysis with high affinity for p-nitrophenyl phosphate bis (cyclohexylammonium) than the widely used p-nitrophenyl phosphate disodium hexahydrate for phosphatase assay. Sweet potato had relatively higher reaction kinetics (Vmax, Km, Kcat, Kcat/Km) values with most substrates tested. The order of catalytic activity was in the order: sweet potato > wheat germ > potato, while the order of substrate hydrolyzed was: PNPBC > PNP > PNP2A2E > DG6P2Na > DG6PNa > Bis-PNP > phytate. The optimum pH for the acid phosphatase was observed to be 5.0. Generally, the activity of alkaline phosphatase was similar to that of acid phosphatase with optimal pH between 10 and 13, depending on the substrates. Knowledge derived from this work would be helpful in enzyme catalysis in soils and water environments.展开更多
Canola crop is rich in plant biomass. It is considered a major cash crop in North America and a potential source for biofuel. We evaluated six strains of white rot basidiomycetes under solid state fermentation (SSF) f...Canola crop is rich in plant biomass. It is considered a major cash crop in North America and a potential source for biofuel. We evaluated six strains of white rot basidiomycetes under solid state fermentation (SSF) for their potentials to secrete oxidative and hydrolytic enzymes to biodegrade canola plant biomass (CPB), and release sugars. Fuscoporia gilva and Pleurotus tuberregium produced high amount of laccase (440.86 U/L and 480.63 U/L at day 7), as well as carboxylmethylcellulase (CMCase) (4.78 U/mL at day 21 and 3.13 U/mL at day 14) and xylanase (4.48 U/mL and 7.8 U/mL at day 21), respectively. Bjerkandera adusta showed high amount of MnP (50.4 U/L) and peroxidase (64.5 U/L), relative to the other strains. Loss of organic matter peaked after 21 days of incubation in all the tested strains;however, the best result (34.0%) was shown in P. tuberregium. The highest lignin loss was observed in Coriolopsis caperata strains. Among the sugar polymers, hemicellulose was highly degraded by P. tuberregium and P. pulmonarius (4.1% - 4.6%), while cellulose (3.3% - 4.3%) was mainly degraded by F. gilva and B. adusta. Glucose was the dominant sugar released by all the fungi tested, with the highest concentration of 1.25 mg/mL produced by B. adusta at day 14 of incubation. Results indicate that selected white rot fungi can achieve significant delignification of CPB within 14 days of solid state fermentation. Their importance in low cost pretreatment of lignocellulosic biomass prior to conversion into biofuels and bio-products of economic importance is discussed.展开更多
Sulfatases which cleave sulfate esters in biological systems are key enzymes that deserve special attention due to their significant roles in organic sulfur (OS) mineralization and inorganic sulfur () release. In this...Sulfatases which cleave sulfate esters in biological systems are key enzymes that deserve special attention due to their significant roles in organic sulfur (OS) mineralization and inorganic sulfur () release. In this study, in-vitro experiments were conducted to evaluate S bonded substrate hydrolysis by a commercially available arylsulfatase (EC 3.1.6.1) from Aerobacter aerogenes. The enzyme-substrate interactions were assessed to determine: 1) rate of hydrolysis, 2) catalytic efficiency, 3) thermal stability, and 4) optimal pH of this enzyme. Arylsulfatase exhibited substrate hydrolysis with a high affinity for p-nitrophenyl sulfate (potassium 4-nitrophenyl sulfate (pNPS)). The optimum activity for the enzyme was observed to occur at a pH of 7.1. The optimal temperature was 37°C but ranged from 35°C - 45°C. The apparent Km and Kcat of the enzyme for pNPS hydrolysis at the optimal pH, and temperature were determined to be 1.03 mM and 75.73 μM/min, respectively. This work defines the catalytic and kinetic properties of arylsulfatase (EC 3.1.6.1) and confirms the optimal conditions for sulfatase activity testing. The resulting information is useful in elucidating the contributions that individual enzymes have for specific reactions rather than relying on traditional total enzyme activity measurements.展开更多
Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WR...Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied showed β-glucosidase activities. Significant variations in protein and carbohydrate contents were also recorded. Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic constant (Km) ranged from 0.47 μM (A. auricular-1120) to 719 μM (L. edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase activities also exhibited pH optima between 3.5 and 5.0 while temperature optima were between 60°C and 70°C with some media exhibiting a secondary temperature peak at 90°C attributable to the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.展开更多
Prescribed burning and tree thinning are commonly used restoration practices for US forests management to increase forest productivity and enhance plant and animal diversity. The impact of these practices in Alabama’...Prescribed burning and tree thinning are commonly used restoration practices for US forests management to increase forest productivity and enhance plant and animal diversity. The impact of these practices in Alabama’s Bankhead National Forest (BNF) to soil microbial components and overall forest soil health are unknown. We hypothesized that microbial assemblages and enzyme activities are continuously changing in forest ecosystems especially due to management selections. Therefore, the objective of this study was to assess changes in microbial community compositions (fungal vs bacterial populations) via fatty acid methyl ester (FAME) profiling and several enzyme activities (β-glucosaminidase, acid phosphatase, arylsulfatase, β-glucosidase, xylanase, laccase, and manganese peroxidase) critical to soil organic matter (SOM) dynamics and biogeochemical cycling. In this forest, heavily-thinned plots without burning or less frequent burning treatments seemed to provide more favorable conditions (higher pH and lower C:N ratios) for C and N mineralization. This may explain a slight increase (by 12%) detected in fungi:bacteria (F:B) ratio in the heavily-thinned plots relative to the control. Thinned (lightly and heavily) plots showed greater ligninolytic (laccase and MnP) activities and lower β-glucosidase and β-glucosaminidase activities compared to the no-thinned plots probably due to increase depositions of woody recalcitrant C materials. We observed significant but negative correlations between the ligninolytic laccase and manganese peroxidase (Lac and MnP) enzymes respectively, with MBC (?0.45* and ?0.68** respectively) and MBN (?0.43* and ?0.65** respectively). Prescribed burning treatment reduced microbial biomass C and N of the 9-yr burned plot/lightly thinned plotsprobably due to depletion of labile C sources with the high temperatures, leaving mostly recalcitrant C sources as available soil substrates. Gram-positive bacteria (i15:0, a15:0, i17:0, and a17:0), actinomycetes (10-Me17:0, 10-Me18:0), AMF (16:1ω5c), and saprophytic fungi (18:1ω9c), largely contributed to the microbial compositions. This study bridges knowledge gaps in our understanding of microbial community compositions and enzyme-mediated processes in repeatedly burned and thinned forest ecosystems.展开更多
Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine bi...Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine biochar-amended soils, comparing multiple enzyme activities (EAs) simultaneously determined in the same soil sample vs. the sum of individual EAs involved in the C, N, S, and P cycles to provide information of the impacts of biochar on biogeochemical cycling. The combination of these four EAs has been considered an indicator of soil health due to their role in the reactions that release bioavailable nutrients in the cycling of C (β-glucosidase), N and C (β-glucosaminidase), P (acid phosphomonoesterase), and S (aryl-sulfatase) in soils. Comparisons of the theoretical EAs and the CNPS activity assay approaches in the biochar-modified soil revealed similar activity trends with the different concentrations of added biochar. Two years after adding biochar, study results showed the amended soils did not retain more pNP substrate than the un-amended control soils in three different pH buffers (5.5, 5.8, and 6.5) commonly used in EA reactions. Finally, we performed a third experiment to determine if the biochar previously added to the EAs interfered with the reactions’ enzyme or substrate. The results indicated that greater activity was measured using the combined assay, which suggests the CNPS activity method was less affected by biochar than the individual EAs. Our findings indicate that the potential soil biochemical-health index, CNPS activity (combination of four enzymes) assay is more robust than the individual EAs and can be used as an alternative tool to monitor soil functioning.展开更多
文摘Biochemical, chemical, and mechanical, techniques have been employed to enhance soil resilience for decades. While the use of mechanical techniques requires transporting huge amounts of soil materials, the cement used in chemical techniques may lead to increase atmospheric carbon dioxide. Numerous studies indicate that biochemical techniques may be less expensive, cost effective, and environmentally friendly. Biopolymers and enzymes derived from microorganisms have been suggested as biological enhancers in strengthening and fortifying soils used for earthen structures. Lime and other treatment techniques used as biobased materials have been shown to be less effective for stabilizing soils. Here, we review biochemical processes and techniques involved in the interactions of soil enzymes, microorganisms, microbial extracellular polymeric substances, and other biopolymers with soil particles, and the challenges and strategies of their use as biobased materials for stabilizing soils. This review provides their impacts on various soil properties and the growth potentials of agricultural crops. .
文摘Phosphatases are diverse groups of enzymes that deserve special attention because of their significant roles in organic phosphorus (OP) mineralization to inorganic available forms (Pi). This work 1) compared the catalytic potentials of commercially acid phosphatase from wheat germ, sweet potato, and potato, and alkaline phosphatase from E. coli;2) demonstrated that the rate of hydrolysis, catalytic efficiency, thermal stability, and optimal pH of these enzymes depended on enzyme sources and the stereochemical or stereoisomeric structures of the substrates;3) revealed that both acid and alkaline phosphatases exhibited broad range of substrate hydrolysis with high affinity for p-nitrophenyl phosphate bis (cyclohexylammonium) than the widely used p-nitrophenyl phosphate disodium hexahydrate for phosphatase assay. Sweet potato had relatively higher reaction kinetics (Vmax, Km, Kcat, Kcat/Km) values with most substrates tested. The order of catalytic activity was in the order: sweet potato > wheat germ > potato, while the order of substrate hydrolyzed was: PNPBC > PNP > PNP2A2E > DG6P2Na > DG6PNa > Bis-PNP > phytate. The optimum pH for the acid phosphatase was observed to be 5.0. Generally, the activity of alkaline phosphatase was similar to that of acid phosphatase with optimal pH between 10 and 13, depending on the substrates. Knowledge derived from this work would be helpful in enzyme catalysis in soils and water environments.
文摘Canola crop is rich in plant biomass. It is considered a major cash crop in North America and a potential source for biofuel. We evaluated six strains of white rot basidiomycetes under solid state fermentation (SSF) for their potentials to secrete oxidative and hydrolytic enzymes to biodegrade canola plant biomass (CPB), and release sugars. Fuscoporia gilva and Pleurotus tuberregium produced high amount of laccase (440.86 U/L and 480.63 U/L at day 7), as well as carboxylmethylcellulase (CMCase) (4.78 U/mL at day 21 and 3.13 U/mL at day 14) and xylanase (4.48 U/mL and 7.8 U/mL at day 21), respectively. Bjerkandera adusta showed high amount of MnP (50.4 U/L) and peroxidase (64.5 U/L), relative to the other strains. Loss of organic matter peaked after 21 days of incubation in all the tested strains;however, the best result (34.0%) was shown in P. tuberregium. The highest lignin loss was observed in Coriolopsis caperata strains. Among the sugar polymers, hemicellulose was highly degraded by P. tuberregium and P. pulmonarius (4.1% - 4.6%), while cellulose (3.3% - 4.3%) was mainly degraded by F. gilva and B. adusta. Glucose was the dominant sugar released by all the fungi tested, with the highest concentration of 1.25 mg/mL produced by B. adusta at day 14 of incubation. Results indicate that selected white rot fungi can achieve significant delignification of CPB within 14 days of solid state fermentation. Their importance in low cost pretreatment of lignocellulosic biomass prior to conversion into biofuels and bio-products of economic importance is discussed.
文摘Sulfatases which cleave sulfate esters in biological systems are key enzymes that deserve special attention due to their significant roles in organic sulfur (OS) mineralization and inorganic sulfur () release. In this study, in-vitro experiments were conducted to evaluate S bonded substrate hydrolysis by a commercially available arylsulfatase (EC 3.1.6.1) from Aerobacter aerogenes. The enzyme-substrate interactions were assessed to determine: 1) rate of hydrolysis, 2) catalytic efficiency, 3) thermal stability, and 4) optimal pH of this enzyme. Arylsulfatase exhibited substrate hydrolysis with a high affinity for p-nitrophenyl sulfate (potassium 4-nitrophenyl sulfate (pNPS)). The optimum activity for the enzyme was observed to occur at a pH of 7.1. The optimal temperature was 37°C but ranged from 35°C - 45°C. The apparent Km and Kcat of the enzyme for pNPS hydrolysis at the optimal pH, and temperature were determined to be 1.03 mM and 75.73 μM/min, respectively. This work defines the catalytic and kinetic properties of arylsulfatase (EC 3.1.6.1) and confirms the optimal conditions for sulfatase activity testing. The resulting information is useful in elucidating the contributions that individual enzymes have for specific reactions rather than relying on traditional total enzyme activity measurements.
文摘Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied showed β-glucosidase activities. Significant variations in protein and carbohydrate contents were also recorded. Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic constant (Km) ranged from 0.47 μM (A. auricular-1120) to 719 μM (L. edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase activities also exhibited pH optima between 3.5 and 5.0 while temperature optima were between 60°C and 70°C with some media exhibiting a secondary temperature peak at 90°C attributable to the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.
文摘Prescribed burning and tree thinning are commonly used restoration practices for US forests management to increase forest productivity and enhance plant and animal diversity. The impact of these practices in Alabama’s Bankhead National Forest (BNF) to soil microbial components and overall forest soil health are unknown. We hypothesized that microbial assemblages and enzyme activities are continuously changing in forest ecosystems especially due to management selections. Therefore, the objective of this study was to assess changes in microbial community compositions (fungal vs bacterial populations) via fatty acid methyl ester (FAME) profiling and several enzyme activities (β-glucosaminidase, acid phosphatase, arylsulfatase, β-glucosidase, xylanase, laccase, and manganese peroxidase) critical to soil organic matter (SOM) dynamics and biogeochemical cycling. In this forest, heavily-thinned plots without burning or less frequent burning treatments seemed to provide more favorable conditions (higher pH and lower C:N ratios) for C and N mineralization. This may explain a slight increase (by 12%) detected in fungi:bacteria (F:B) ratio in the heavily-thinned plots relative to the control. Thinned (lightly and heavily) plots showed greater ligninolytic (laccase and MnP) activities and lower β-glucosidase and β-glucosaminidase activities compared to the no-thinned plots probably due to increase depositions of woody recalcitrant C materials. We observed significant but negative correlations between the ligninolytic laccase and manganese peroxidase (Lac and MnP) enzymes respectively, with MBC (?0.45* and ?0.68** respectively) and MBN (?0.43* and ?0.65** respectively). Prescribed burning treatment reduced microbial biomass C and N of the 9-yr burned plot/lightly thinned plotsprobably due to depletion of labile C sources with the high temperatures, leaving mostly recalcitrant C sources as available soil substrates. Gram-positive bacteria (i15:0, a15:0, i17:0, and a17:0), actinomycetes (10-Me17:0, 10-Me18:0), AMF (16:1ω5c), and saprophytic fungi (18:1ω9c), largely contributed to the microbial compositions. This study bridges knowledge gaps in our understanding of microbial community compositions and enzyme-mediated processes in repeatedly burned and thinned forest ecosystems.
文摘Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine biochar-amended soils, comparing multiple enzyme activities (EAs) simultaneously determined in the same soil sample vs. the sum of individual EAs involved in the C, N, S, and P cycles to provide information of the impacts of biochar on biogeochemical cycling. The combination of these four EAs has been considered an indicator of soil health due to their role in the reactions that release bioavailable nutrients in the cycling of C (β-glucosidase), N and C (β-glucosaminidase), P (acid phosphomonoesterase), and S (aryl-sulfatase) in soils. Comparisons of the theoretical EAs and the CNPS activity assay approaches in the biochar-modified soil revealed similar activity trends with the different concentrations of added biochar. Two years after adding biochar, study results showed the amended soils did not retain more pNP substrate than the un-amended control soils in three different pH buffers (5.5, 5.8, and 6.5) commonly used in EA reactions. Finally, we performed a third experiment to determine if the biochar previously added to the EAs interfered with the reactions’ enzyme or substrate. The results indicated that greater activity was measured using the combined assay, which suggests the CNPS activity method was less affected by biochar than the individual EAs. Our findings indicate that the potential soil biochemical-health index, CNPS activity (combination of four enzymes) assay is more robust than the individual EAs and can be used as an alternative tool to monitor soil functioning.
