Reversal of enzymatic hydrolysis: Rate and extent of ester synthesis as catalyzed by chymotrypsin and subtilisin Carlsberg at low water concentrations

The aims of this study were to characterize the kinetics of enzymatic hydrolysis of sago starch, obtained from Southeast Sulawesi Indonesia. The enzyme used for hydrolysis was bacterial ∝-amylase (Termamyl 120L from Bacillus licheniformis, E. C. 3.2.1.1). The method to determine the initial velocity (Vo) of the hydrolysis was developed by differentiation a nonlinear equation (NLE). The Vo of the hydrolysis was measured at various pH (6.0, 6.5,and 7.0), temperatures (40, 60, 75 and 95oC), enzyme concentrations (0.5, 1.0, 1.5 and 2.0 µg per mL) and in the presence of 70 ppm Ca++. The optimum conditions of this experiment were found to be at pH 6.5 – 7.0 and 75oC, and the Vo increased with increasing enzyme concentration. The Vo values at various substrate concentrations were also determined, which were then used to calculate the enzymes kinetics constant of the hydrolysis, including Michaelis-Menten constant (Km) and maximum velocity (Vmax) using a Hanes plot. Km and Vmax values were found to be higher in the measurement at pH 7.0 and 75oC. The Km values at four different combinations of pH and temperatures (pH 6.5, 40oC; pH 6.5, 75oC; pH 7.0, 40oC; pH 7.0, 75oC) were found to be 0.86, 3.23, 0.77 and 3.83 mg/mL, respectively; and Vmax values were 17.5, 54.3, 20.3 and 57.1 µg/mL/min, respectively. The results obtained showed that hydrolysis rate of this starch was somewhat low.

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A Comprehensive Approach of Eucalyptus globulus Acid Sulfite Pretreatment for Enzymatic Hydrolysis

Applied Sciences ◽

10.3390/app10113764 ◽

2020 ◽

Vol 10 (11) ◽

pp. 3764

Author(s):

Vera D. Costa ◽

Ana Costa ◽

Maria Amaral ◽

Rogério S. Simões

Keyword(s):

Sulfuric Acid ◽

Enzymatic Hydrolysis ◽

Eucalyptus Globulus ◽

High Performance ◽

Sodium Bisulfite ◽

Hydrolysis Rate ◽

Hemicellulose Removal ◽

Pretreatment Temperature ◽

Pretreatment Conditions ◽

Very High

The effect of different acid sulfite pretreatment conditions on released components in the hydrolysates and the pretreated solid residues’ response to enzymatic hydrolysis for Eucalyptus globulus chips was investigated. Sodium bisulfite (0–15%), and sulfuric acid (0–5%) were used to pretreat chips at 170 °C and 190 °C, for as long as 30 min. The hydrolysates were analyzed through high-performance liquid chromatography (HPLC) and spectrophotometry. Overall porosity and pores larger than 2.65 nm (size of a typical cellulase) on the solid residues were estimated using glucose and two dextrans with different hydrodynamic radii as probes. The external specific surface area was analyzed by dynamic light scattering. The solid residues underwent enzymatic hydrolysis with an enzymatic cocktail. Very high (84–95%) carbohydrate conversion was achieved for either an extensively delignified biomass or a biomass with very high content of sulfonated residual lignin (23.4%), since internal porosity enables enzymes accessibility. At least 5% sodium bisulfite and 1% sulfuric acid was required to attain a carbohydrate release above 90% in the enzymatic hydrolysis. Results suggest that the presence of sulfonated lignin does not impair the enzymatic hydrolysis rate and extent. The increase of pretreatment temperature had a positive effect mainly on the initial rate of carbohydrates release in the enzymatic hydrolysis. The increase of the wood material dimensions from pins to conventional chips significantly decreased the hemicellulose removal in acid sulfite pretreatment but had a small effect on the enzymatic yield.

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Modification of microcrystalline cellulose structural properties by ball-milling and ionic liquid treatments and their correlation to enzymatic hydrolysis rate and yield

Cellulose ◽

10.1007/s10570-019-02578-8 ◽

2019 ◽

Vol 26 (12) ◽

pp. 7323-7335 ◽

Cited By ~ 3

Author(s):

Felipe Tadeu Fiorini Gomide ◽

Ayla Sant’Ana da Silva ◽

Elba Pinto da Silva Bon ◽

Tito Lívio Moitinho Alves

Keyword(s):

Ionic Liquid ◽

Enzymatic Hydrolysis ◽

Ball Milling ◽

Structural Properties ◽

Microcrystalline Cellulose ◽

Hydrolysis Rate

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The enzymatic hydrolysis rate of cellulose decreases with irreversible adsorption of cellobiohydrolase I

Enzyme and Microbial Technology ◽

10.1016/j.enzmictec.2008.02.009 ◽

2008 ◽

Vol 42 (7) ◽

pp. 543-547 ◽

Cited By ~ 49

Author(s):

Anzhou Ma ◽

Qing Hu ◽

Yinbo Qu ◽

Zhihui Bai ◽

Weifeng Liu ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Hydrolysis Rate ◽

Cellobiohydrolase I ◽

Irreversible Adsorption

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Influence of Homogenization Treatment on Physicochemical Properties and Enzymatic Hydrolysis Rate of Pure Cellulose Fibers

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-012-0057-2 ◽

2013 ◽

Vol 169 (4) ◽

pp. 1315-1328 ◽

Cited By ~ 8

Author(s):

N. Jacquet ◽

C. Vanderghem ◽

S. Danthine ◽

C. Blecker ◽

M. Paquot

Keyword(s):

Enzymatic Hydrolysis ◽

Physicochemical Properties ◽

Cellulose Fibers ◽

Hydrolysis Rate ◽

Homogenization Treatment ◽

Pure Cellulose

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Preliminary Study on Natural Freeze-Thaw Pretreatment of Wheat Straw

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.550-553.472 ◽

2012 ◽

Vol 550-553 ◽

pp. 472-475 ◽

Cited By ~ 1

Author(s):

Meng Yu ◽

Lian Jie Wang ◽

Xin Ming Wang

Keyword(s):

Particle Size ◽

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Treatment Effectiveness ◽

Cold Weather ◽

Hydrolysis Rate ◽

Wet Milling ◽

Freezing And Thawing ◽

Freeze Thaw ◽

The Difference

The straw biomass pretreatment technology is the key to the study of fuel ethanol. Freeze-thaw pretreatment of wheat straw is in its infancy. In this paper, we investigated influencing factors including the ratio of solid to liquid, crushed particle size, the difference of the solid to liquid in the wet milling processing. When the solid-liquid ratio is 1:18, hydrolysis rate can be increased by 17.93% and when crushed particle size of 120 meshes, enzymatic hydrolysis rate of 39.55%. Due to the traditional freeze-thaw technology is simply freezing and thawing process, the enzymatic hydrolysis rate only can be increased by about 15%. Therefore, we improve traditional process by wet grinding and freeze-thaw combining at the same time to take advantage of the cold weather in winter for the purpose to improve treatment effectiveness and feasibility of freezing and thawing. After this treatment, enzymatic hydrolysis rate increased by 57.50%.

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Synergistic Effect of Enzyme Hydrolysis and Microwave Reactor Pretreatment as an Efficient Procedure for Gluten Content Reduction

Foods ◽

10.3390/foods10092214 ◽

2021 ◽

Vol 10 (9) ◽

pp. 2214

Author(s):

Ivana Gazikalović ◽

Jelena Mijalković ◽

Nataša Šekuljica ◽

Sonja Jakovetić Tanasković ◽

Aleksandra Đukić Vuković ◽

...

Keyword(s):

Heat Treatment ◽

Enzymatic Hydrolysis ◽

Wheat Gluten ◽

Control Process ◽

Enzyme Hydrolysis ◽

Hydrolysis Rate ◽

Microwave Pretreatment ◽

Microwave Reactor ◽

Conventional Heat Treatment ◽

Functional Features

In this study, we assessed the effects of microwave irradiation of wheat gluten proteins as a pretreatment performed in a microwave reactor that could accurately control process parameters as a function of power and temperature, as well as comparing it with conventional heat treatment. The aim was to identify suitable combinations of partial enzymatic hydrolysis and microwave pretreatment parameters to produce gluten hydrolysates with reduced allergenicity and conserved techno-functional features for food application. FTIR analysis, and total and reactive SH group contents confirmed that the microwave-controlled heating can significantly change the secondary structure and conformation of gluten protein. The microwave treatment had the largest effect at 200 W and 100 °C, at which the content of gluten has been reduced by about 2.5-fold. The microwave pretreatment also accelerated the enzymatic hydrolysis of gluten, changing the kinetic profile. The apparent hydrolysis rate constants (k2) were 1.00, 3.68, 3.48, 4.64 and 4.17 min−1 for untreated gluten, and those pretreated with microwave power of 200, 400, 600 and 800 W, respectively. Compared to the heat treatment, it appeared that microwave specific non-thermal effects had a significant influence on the gluten structure and allergenicity and, in combination with the enzymatic hydrolysis, ultimately yielded protein hydrolysates with enhanced antioxidant and functional properties.

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Dilute alkali pretreatment and subsequent enzymatic hydrolysis of amur silvergrass for ethanol production

BioResources ◽

10.15376/biores.15.3.4823-4834 ◽

2020 ◽

Vol 15 (3) ◽

pp. 4823-4834

Author(s):

Fengqin Gao ◽

Fuyu Yang ◽

Ying De ◽

Ya Tao ◽

Na Ta ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Ethanol Production ◽

Residence Time ◽

Orthogonal Experiment ◽

Influencing Factor ◽

Hydrolysis Rate ◽

Single Factor ◽

Liquid Ratio ◽

Alkali Pretreatment ◽

Sem Images

A dilute alkali pretreatment (NaOH) was used to remove lignin and some hemicelluloses, as well as to efficiently increase the accessibility of enzymes to the cellulose in Amur silvergrass. A single factor experiment was designed with 4 factors (1 to 5% w/w NaOH, 1/6 to 1/14 solid to liquid ratio, 15 to 90 min residence time, and 80 to 125 °C digestion temperature) with 3 duplicates of 5 levels for each factor. On the basis of the single factor test, an L8 (24)-orthogonal experiment was conducted to identify the main influencing factor and the optimal factor combinations verified by an enzymatic hydrolysis and fermentation experiment. The main factors influencing ethanol production were NaOH concentration and digestion temperature, while residence time and solid to liquid ratio had a lesser effect. The enzymatic hydrolysis rate of cellulose reached 82.6%, and the highest conversion rate of ethanol was 78.3% with 4.0% (w/w) NaOH and a 1:6 solid to liquid ratio at 100 °C for 15 min. Scanning electron microscope (SEM) images of the lignocellulosic surface structure of non-pretreated and optimum pretreated Amur silvergrass displayed obvious differences. The lignin was the key recalcitrance-causing factor for ethanol production, which can be effectively removed by the NaOH.

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