The major objective of this experimental study is to investigate and compare the corrosion resistance of medium Carbon steel (MCS) and KS7 stainless steel in saline and sodium carbonate environments. The MCS and KS7 S...The major objective of this experimental study is to investigate and compare the corrosion resistance of medium Carbon steel (MCS) and KS7 stainless steel in saline and sodium carbonate environments. The MCS and KS7 SS were exposed to 0.5 M each of NaCl and Na2CO3 solutions for a period of 36 days. The weight loss was taken every 3 days in order to evaluate CPR. The results obtained showed that KS7 SS generally offers a better corrosion resistance than the MCS in the selected media. While MCS is found to be inappropriate alloy in saline and sodium carbonate environments, KS7 SS is an unfailing choice material for manufacturing machines and other engineering amenities in which their service lives are predominant in Na2CO3 medium and fairly pleasing in NaCl environment.展开更多
Cellulose is the main component of lignocellulose and its degradation requires the participation of three enzymes,namely glucan endopeptidase,glucan exopeptidase andβ-glucosidase(BGL).The intermediate cellobiose prod...Cellulose is the main component of lignocellulose and its degradation requires the participation of three enzymes,namely glucan endopeptidase,glucan exopeptidase andβ-glucosidase(BGL).The intermediate cellobiose produced in the hydrolysis process will negatively feedback on the process by inhibiting the activity of cellulases,but BGLs can effectively relieve the inhibition through a further conversion of the intermediate to the end product glucose and are thus considered the key enzyme in the pathway.However,most BGLs are inhibited by glucose.Ks5A7 is a novel enzyme that shows high activity and decent tolerance toward glucose and thus poses an ideal enzyme,but the underlying structural basis is currently unclear.Here we report the high-resolution structures of Ks5A7 and its variant,which exhibits a typical(β/α)8 TIM-barrel architecture.Through docking studies,we identified potential key contacting residues and investigated its molecular mechanism.Most mutations rendered the enzyme inactive or showed little improvement on enzymatic performance,indicating little tolerance for the structural modifications near the active site of Ks5A7.Nevertheless,we obtained a mutation A218N that shows more superior thermostability,which rewires the local environment and allows for better communications with the well-documented residue Ala298.Structural studies and molecular dynamics(MD)simulation revealed that the mutant steadily secures the substrate at the active site and provides a better local structural stability than the wild-type(WT)for catalysis.Lastly,the practical applicability scenarios were also discussed.Taken together,this study sheds lights on the structure-activity relationship and evolutionary pathways of Ks5A7.展开更多
文摘The major objective of this experimental study is to investigate and compare the corrosion resistance of medium Carbon steel (MCS) and KS7 stainless steel in saline and sodium carbonate environments. The MCS and KS7 SS were exposed to 0.5 M each of NaCl and Na2CO3 solutions for a period of 36 days. The weight loss was taken every 3 days in order to evaluate CPR. The results obtained showed that KS7 SS generally offers a better corrosion resistance than the MCS in the selected media. While MCS is found to be inappropriate alloy in saline and sodium carbonate environments, KS7 SS is an unfailing choice material for manufacturing machines and other engineering amenities in which their service lives are predominant in Na2CO3 medium and fairly pleasing in NaCl environment.
基金supported by the National Natural Science Foundation of China[32271322]the Natural Science Foundation of the Guangdong Province[2022A1515011768],[2022A1515012574].
文摘Cellulose is the main component of lignocellulose and its degradation requires the participation of three enzymes,namely glucan endopeptidase,glucan exopeptidase andβ-glucosidase(BGL).The intermediate cellobiose produced in the hydrolysis process will negatively feedback on the process by inhibiting the activity of cellulases,but BGLs can effectively relieve the inhibition through a further conversion of the intermediate to the end product glucose and are thus considered the key enzyme in the pathway.However,most BGLs are inhibited by glucose.Ks5A7 is a novel enzyme that shows high activity and decent tolerance toward glucose and thus poses an ideal enzyme,but the underlying structural basis is currently unclear.Here we report the high-resolution structures of Ks5A7 and its variant,which exhibits a typical(β/α)8 TIM-barrel architecture.Through docking studies,we identified potential key contacting residues and investigated its molecular mechanism.Most mutations rendered the enzyme inactive or showed little improvement on enzymatic performance,indicating little tolerance for the structural modifications near the active site of Ks5A7.Nevertheless,we obtained a mutation A218N that shows more superior thermostability,which rewires the local environment and allows for better communications with the well-documented residue Ala298.Structural studies and molecular dynamics(MD)simulation revealed that the mutant steadily secures the substrate at the active site and provides a better local structural stability than the wild-type(WT)for catalysis.Lastly,the practical applicability scenarios were also discussed.Taken together,this study sheds lights on the structure-activity relationship and evolutionary pathways of Ks5A7.
