Enzymatic Hydrolysis Tests Research Articles

Characterization of exopolysaccharide (EPS) produced by Weissella hellenica SKkimchi3 isolated from kimchi

Weissella hellenica SKkimchi3 produces the higher exopolysaccharide (EPS) on sucrose than lactose, glucose, and fructose at pH 5 and 20 degrees C. Sucrose was exclusively used to cultivate SKkimchi3 in all experiments base on the EPS production tests. The molecular mass of EPS, as determined by gel permeation chroma-tography, was 203,000. (1)H and (13)C NMR analysis indicated that the identity of EPS may be a glucan. When EPS, starch, and cellulose was treated with a-amylase, glucoamylase, glucosidase, and cellulase, glucose was produced from starch and cellulose but was not produced from EPS. Based on HPLC analysis, elemental analysis, (1)H and (13)C NMR analysis, and enzymatic hydrolysis tests, EPS was estimated to be a glucan. EPS suspension was not precipitated even by centrifugation at 10,000xg for 60 min, and EPS made the fermented milk and bacterial culture viscous.

Effect of inhibitors released during steam-explosion treatment of poplar wood on subsequent enzymatic hydrolysis and SSF.

Steam-exploded (SE) poplar wood biomass was hydrolyzed by means of a blend of Celluclast and Novozym cellulase complexes in the presence of the inhibiting compounds produced during the preceding steam-explosion pretreatment process. The SE temperature and time conditions were 214 degrees C and 6 min, resulting in a log R(0) of 4.13. In enzymatic hydrolysis tests at 45 degrees C, the biomass loading in the bioreactor was 100 g(DW)/L (dry weight) and the enzyme-to-biomass ratio 0.06 g/g(DW). The enzyme activities for endo-glucanase, exo-glucanase, and beta-glucosidase were 5.76, 0.55, and 5.98 U/mg, respectively. The inhibiting effects of components released during SE (formic, acetic, and levulinic acids, furfural, 5-hydroxymethyl furfural (5-HMF), syringaldehyde, 4-hydroxy benzaldehyde, and vanillin) were studied at different concentrations in hydrolysis runs performed with rinsed SE biomass as model substrate. Acetic acid (2 g/L), furfural, 5-HMF, syringaldehyde, 4-hydroxybenzaldehyde, and vanillin (0.5 g/L) did not significantly effect the enzyme activity, whereas formic acid (11.5 g/L) inactivated the enzymes and levulinic acid (29.0 g/L) partially affected the cellulase. Synergism and cumulative concentration effects of these compounds were not detected. SSF experiments show that untreated SE biomass during the enzymatic attack gives rise to a nonfermentable hydrolysate, which becomes fermentable when rinsed SE biomass is used. The presence of acetic acid, vanillin, and 5-HMF (0.5 g/L) in SSF of 100 g(DW) /L biomass gave rise to ethanol yields of 84.0%, 73.5%, and 91.0% respectively, with respective lag phases of 42, 39, and 58 h.

Preparation of Hydrophilic Polyhydroxyalkyl Glutamine Crosslinked Films and its Biodegradability

Polybenzyl glutamate (PBLG) or polymethyl glutamate (PMLG) films have been aminolyzed with amino alcohol and crosslinked with aliphatic diamine at 60 degrees C for 48 h simultaneously which led to the formation of crosslinked films of polyhydroxyalkyl glutamine (PHAG). ATR-IR indicates that for the aminolysis of PBLG with 2-amino-1-ethanol or 3-amino-1-propanol, benzyl glutamate almost completely turned to hydroxyalkyl glutamine, however for the aminolysis of PMLG with 5-amino-1-pentanol, methyl glutamate partially turned to hydroxypentanyl glutamine. The water-swelling test shows that water-swelling ratio Q of PHAG films from amino alcohol with longer carbon chain was smaller, the PHAG films crosslinked by 1,2-diamino ethane have the higher water-swelling ratio Q, but the PHAG films crosslinked by 1,8-diamino octane have the lower water swelling ratio Q; and PHAG films with a greater amount of crosslinking agents have high crosslinking density or the low water swelling-ratio Q for same amino alcohol and diamine. It is obvious from in vitro enzymatic hydrolysis test that specimens with smaller swelling ratio Q displayed larger T(1/2), time for half weight digestion of PHAG film, that is, less biodegradability. Therefore, biodegradability of the crosslinked PHAG films can be controlled by changing amino alcohol and diamine.

Enzymatic pre-hydrolysis applied to the anaerobic treatment of effluents from poultry slaughterhouses

A pool of hydrolases with 21.4 U g −1 lipase activity was produced through solid-state fermentation of the fungus Penicillium restrictum in waste from the Orbignya oleifera (babassu) oil processing industry. Enzymatic hydrolysis and anaerobic biodegradability tests were conducted on poultry slaughterhouse effluents with varying oil and grease contents (150–1200 mg l −1) and solid enzymatic pool concentrations (0.1–1.0% w/v). Enhanced anaerobic treatment efficiency relative to raw effluent was achieved when a 0.1% concentration of enzymatic pool was used in the pre-hydrolysis stage with 1200 mg oil and grease l −1 (chemical oxygen demand (COD) removal efficiency of 85% vs. 53% and biogas production of 175 ml vs. 37 ml after 4 d).

Effect of Inhibitors Released During Steam-Explosion Pretreatment of Barley Straw on Enzymatic Hydrolysis

The influence of the liquid fraction (prehydrolysate) generated during steam-explosion pretreatment (210 degrees C, 15 min) of barley straw on the enzymatic hydrolysis was determined. Prehydrolysate was analyzed for degradation compounds and sugars' content and used as a medium for enzymatic hydrolysis tests after pH adjusting to 4.8. Our results show that the presence of the compounds contained in the prehydrolysate strongly affects the hydrolysis step (a 25% decrease in cellulose conversion compared with control). Sugars are shown to be more potent inhibitors of enzymatic hydrolysis than degradation products.

A Study of Biodegradable Superabsorbent Materials Based on Acrylonitrile Grafted Sodium Alginate

Biodegradable superabsorbents, hydrolyzed AN(acrylonitrile)-grafted-SA(sodium alginate) copolymers were prepared in this study by graft copolymerization of acrylonitrile on sodium alginate and the subsequent hydrolysis of the resulting grafted copolymer. The absorbency was found to significantly depend on the % add-on, graft copolymerization conditions and hydrolysis conditions. The optimum condition for graft copolymerization to obtain the maximum % add-on (64.5%) was 4g SA, 12g AN, and 8.42g H2O2 in 100ml water at 70 oC for 10hr., respectively. The optimum hydrolysis conditions for the graft copolymer (64.5 % add-on) to reach the maximum water absorbency (2518g/g), saline absorbency (1558g/g), and WRV (288g/g) is 1g graft copolymer in 10 ml aqueous NaOH (1.0N) at 110 oC for 1 hr. Furthermore, this hydrolyzed AN-graft-SA showed a good biodegradability in enzymatic hydrolysis tests when compared with commercial superabsorbent materials.

Methodology in studying improvement of polyacrylates biodegradability

AbstractThe biodegradability of polyacrylic acid derivatives may be improved through introduction of some fragility points within the main carbon chains. These weakness points can be either hydrolizable bonds or oxidizable sites. Enzymatic hydrolysis and oxydative biomimetic degradation tests have been set up in order to quickly evaluate new polymeric structures, before their possible evaluation through microbial degradation by Candida tropicalis.

Synthesis and biodegradation of poly(γ-butyrolactone-co-l-lactide)

Biodegradable polyesters were synthesized by ring-opening copolymerization of γ-butyrolactone (BL) and its derivatives withl-lactide (LLA). Although tetraphenyl tin was the main catalyst used, other organometallic catalysts were used as well.1H and13C NMR spectra showed that poly(BL-co-LLA)s were statistical and that their number-average molecular weights were as high as 7×104. The maximum BL content obtained from copolymerization BL/LLA was around 17%. TheTm andTg values of the copolymers showed a gradual depression with an increase in BL content. NoTm was obtained for the copolymers containing more than 13 mol% BL. The biodegradability of the copolyesters was evaluated by enzymatic hydrolysis and nonenzymatic hydrolysis tests. The enzymatic hydrolysis was carried out at 37°C for 24 h using lipases fromRhizopus arrhizus andR. delemar. Hydrolyses by both lipases showed that an increase in BL content of the copolymer resulted in enhanced biodegradability. Nonenzymatic accelerated hydrolysis of copolymers at 70°C was found to increase proportionally to their exposure time. The hydrolysis rate of these copolymers was considerably faster than that of PLLA. The higher hydrolyzability was recorded for the BL-rich copolymers. The copolymerization of γ-methyl-γ-butyrolactone (MBL) or γ-ethyl-γ-butyrolactone (EBL) with LLA resulted in relatively LA-rich copolymers.

O, O′-(1,4-xylylene) bispilocarpic acid esters as new potential double prodrugs of pilocarpine for improved ocular delivery. II. Physicochemical properties, stability, solubility and enzymatic hydrolysis

Various O, O′-(1,4-xylylene) bispilocarpic acid esters, i.e. bispilocarpic acid diesters, were evaluated as water-soluble double prodrugs of pilocarpine. All the prodrug derivatives (log P = 2.76–7.03) were more lipophilic than pilocarpine (log P = 0.01) asg determined from partitioning between 1-octanol and buffer (pH 7.40) or from LC capacity factors. The bispilocarpic acid diester fumarates were shown to be more water-soluble prodrugs than previously described pilocarpic acid diester fumarates. The aqueous stability of the derivatives was investigated as a function of pH and temperature. Maximal stability was achieved in acidic solutions. The shelf-life of O, O′-dipropionyl (1,4-xylylene) bispilocarpate fumarate was 469 days at pH 6.0 and 4 ° C. Hence, the bispilocarpic acid diester prodrugs possess sufficient aqueous stability to allow formulation of ready-to-use solutions. The diesters were hydrolyzed enzymatically to yield bispilocarpic acid monoester which cyclized to the parent pilocarpine in quantitative amounts. The half-lives of diesters in human plasma varied from 2 to 94 min, being highly dependent on the ester group. It appears that bispilocarpic acid diesters are a promising group of new pilocarpine prodrugs that offer possibilities from the results in stability, solubility, lipophilicity, and enzymatic hydrolysis tests.

Synthesis of .BETA.-1,4-glucan by the .BETA.-transglucosylase of Sclerotinia libertiana.

The β-transglucosylase of Sclerotinia libertiana catalyzed the reaction transferring the non-reducing end glucose of cellotetraitol (G4-OH) to the non-reducing end glucose of G4-OH, and both G3-OH and G5-OH were produced in the reaction at first. A water-insoluble glucan was synthesized by the enzyme, accompanied by the production of soluble cellooligosaccharides such as cellobiose, cellotriose, cellopentaose, and cellohexaose in a prolonged reaction with 2% cellotetraose. The water-insoluble glucan was found to be a linear β-1,4-glucan having an average degree of polymerization of 14 by enzymatic hydrolysis test, methylation, and X-ray analyses. From the results, the β-transglucosylase of Sclerotinia libertiana was defined as a new enzyme able to synthesize higher cellodextrin by a disproportionation reaction of lower molecular weight cellooligosaccharides.

Biological Disposition of Apomorphine IV. Isolation and Characterization of “Bound” Apomorphine

“Bound” apomorphine, the major metabolic product of apomorphine, has been isolated from the urine of rabbits by a series of ion exchange procedures, fractionated by paper chromatography, and identified by enzymatic hydrolysis and various color tests. It has been found to consist of two metabolites which, based on electronic absorption and stereochemical consideration, are designated as apomorphine 3,O-sorption and 4,O-β-glucuronides, respectively.