Characterization of three different potato starches and kinetics of their enzymatic hydrolysis by an α-amylase

Co-immobilized enzymes in magnetic chitosan beads for improved hydrolysis of macromolecular substrates under a time-varying magnetic field

“…While diffusing into the pores of the particle, the small oligosaccharides are also further degraded by the ␣-amylase entrapped in the interior of the beads, resulting in greater intraparticle mass transfer (since smaller molecules have higher diffusion coefficients). When Zulkowski starch (a partly degraded starch with a lower mean molecular weight) (Heitmann et al, 1997) was used as substrate, instead of soluble (potato) starch, we did note that efficient glucose production could be achieved using magnetic chitosan beads immobilized with only glucoamylase (data not shown). In the subsequent experiments to examine starch hydrolysis in batch reactors, soluble (potato) starch was used with beads in the 150-300 m size range co-immobilized at an enzyme mass loading ratio of 6:4 (A:G).…”

Thermal inactivation and reactivity of β-glucosidase immobilized on chitosan–clay composite

“…The slope of the straight line is the initial rate of reaction V (mM/min). The relation between the rate of reaction and substrate concentration can be described by the Michaelis-Menten equation [5,7,8,[28][29][30].…”

“…It was reported that the K M value of immobilized laccase is 4.6 times larger than that of free laccase, but immobilization decreases the V max value from 6.6 × 10 −3 to 5.9 × 10 −3 mM/min [28]. Comparison of the K M value for given free and immobilized enzymes provides information about interaction between an enzyme and its support [29]. An increase in K M once an enzyme has been immobilized indicates that the immobilized enzyme has an apparently lower affinity for its substrate than a free enzyme does, which may be caused by steric hindrance of the active site by the support, the loss of enzyme flexibility necessary for substrate binding or diffusion resistance to solute transport near the beads of the support.…”

Production of pullulan from raw potato starch hydrolysates by a new strain of Auerobasidium pullulans

“…55 Raw sweet potato, a cheap and available agriculture product, is a mixture of 77% 56 amylopectin and 23% amylase and a suitable feedstock for industrial fermentation. 57 Amylose is a polymer built of linear α-1,4-linked glucose monomers, while 58 amylopectin differs from amylose by α-1,6 branching of linear amylose chains [4]. 59 Raw potato starch can be hydrolysed by amylases including amylases.…”

“…The amylases 60 reported to be used for hydrolysis of native potato starch were porcine pancreatic 61 α-amylase [5], thermostable α-amylase from Bacillus sp. I-3 [6], amylase from marine A c c e p t e d M a n u s c r i p t 4 yeast Aureobasidium pullulans N13d [7], α-amylase from Bacillus subtilis [4] In the present investigation, the marine cold-adapted α-amylase produced by 74 E.coli BL21/pEtac-amy derived from marine Pseudoalteromonas arctica GS230 was 75 used for hydrolysis of raw potato starch and the hydrolysates were used for pullulan 76 production by a new strain of Auerobasidium Pullulans isolated from sea mud. starch.…”