ABSTRACT
OBJECTIVE: To obtain novel glucoamylase from Daqu microbe. RESULTS: A dominant strain known as LZ2 with high activity of hydrolyzing starch was isolated from Luzhou Daqu, a Chinese traditional fermentation starter. The LZ2 was identified as Aspergillus oryzae by 18S rDNA sequence analysis. Glucoamylase from LZ2, named as GA-LZ2, was purified to homogeneity and showed a single band with expected molecular mass of 60 kD. The GA-LZ2 effectively degraded amylose, rice starch and wheat starch. Optimal temperature and pH value of enzyme were 60 °C and pH 4.0 respectively. The GA-LZ2 displayed significant thermal stability and pH stability at moderate temperature and low pH. Intriguingly, the thermostability was enhanced in the presence of starch. In addition, GA-LZ2 exhibited insensitivity to glucose, independence of metal ions and tolerance to organic solvents. The GA-LZ2 retained complete activity in the presence of 100 mM glucose and 5% ethanol and methanol. CONCLUSION: Glucoamylase GA-LZ2 displayed broad substrate specificity, strong stability and tolerance, suggesting that GA-LZ2 carry potential for industrial application in bioethanol production.
Subject(s)
Aspergillus oryzae/classification , Glucan 1,4-alpha-Glucosidase/isolation & purification , RNA, Ribosomal, 18S/genetics , Sequence Analysis, DNA/methods , Amylose/chemistry , Aspergillus oryzae/enzymology , Aspergillus oryzae/genetics , Aspergillus oryzae/isolation & purification , DNA, Fungal/genetics , DNA, Ribosomal/genetics , Enzyme Stability , Fermented Foods , Fungal Proteins/isolation & purification , Fungal Proteins/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/metabolism , Hot Temperature , Hydrogen-Ion Concentration , PhylogenyABSTRACT
Sodium alginate/Na(+)rectorite-graft-itaconic acid/acrylamide (SA/Na(+)REC-g-IA/AM) hydrogel film was prepared via solution polymerization. The effect of Na(+)REC, KPS, and NMBA content and the ratio of IA to AM on graft ratio, graft efficiency and absorption of liquids were investigated. The structure and morphology were analyzed by FTIR, XRD, TEM and SEM. Results revealed that the optimal Na(+)REC, KPS, and NMBA content and the ratio of IA to AM were 2wt%, 0.8wt%, 0.38wt% and 4, respectively. The hydrogel film was found to exhibit an intercalative structure and coarse surface. The mechanism of graft copolymerization was discussed. A slower and more continuous release of salicylic acid for SA/Na(+)REC-g-IA/AM composite hydrogel film was shown in vitro drug-controlled release studies, in comparison with SA film. The salicylic acid release mechanism of SA/Na(+)REC-g-IA/AM hydrogel film followed Fickian diffusion.
Subject(s)
Acrylamide/chemistry , Alginates/chemistry , Aluminum Silicates/chemistry , Delayed-Action Preparations/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Minerals/chemistry , Succinates/chemistry , Acrylamide/chemical synthesis , Alginates/chemical synthesis , Aluminum Silicates/chemical synthesis , Anti-Infective Agents/administration & dosage , Cations, Monovalent/chemical synthesis , Cations, Monovalent/chemistry , Delayed-Action Preparations/chemical synthesis , Glucuronic Acid/chemical synthesis , Glucuronic Acid/chemistry , Hexuronic Acids/chemical synthesis , Hexuronic Acids/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate/chemical synthesis , Minerals/chemical synthesis , Polymerization , Salicylic Acid/administration & dosage , Succinates/chemical synthesisABSTRACT
Sodium alginate/Na(+)-rectorite (SA/Na(+)REC) intercalated nano-composite microspheres were prepared in an inverse suspension system. The effect of the preparation conditions of SA/Na(+)REC composite microspheres on adsorption capacity for Basic Blue 9 was investigated. The structure and morphology were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the optimal condition was that the amount of Na(+)-rectorite was 2wt%, the amount of cross-linker was 0.384% and the amount of the initiator was 8%. SEM showed that it is porous products with spherical particulate surface. XRD showed that intercalation is formed between Na(+)-rectorite and sodium alginate. The adsorption capacity of SA/Na(+)REC was investigated in comparison with Na(+)-rectorite and sodium alginate using different cationic dyes. The SA/Na(+)REC composite microspheres showed the highest adsorption capacity. The reason lies in the existence of intercalated sodium alginate. It could enlarge the pore structure of microspheres, facilitating the penetration of macromolecular dyes.