scholarly journals Effect and optimization of NaOH combined with Fenton pretreatment conditions on enzymatic hydrolysis of poplar sawdust

Author(s):  
Fei Li ◽  
Xiaohong Lu ◽  
Yiming Li ◽  
Xia Zhou ◽  
Zhezhen Zhao ◽  
...  

Abstract In this study, the effects and mechanism of pretreatments of three types of chemical reagents combined with Fenton on poplar sawdust were studied and the optimization of enzymatic hydrolysis conditions was conducted using response surface methodology. The results showed that cellulase and hemicellulase had the best hydrolysis effect after NaOH-Fenton pretreatment, which were 63.73% and 29.29%, respectively. The optimal process of poplar substrate was to react in 1% NaOH at 100 ℃ for 1 h, then placed in the Fenton reaction system of 0.2 mmol Fe2+ and 25 mmol H2O2 for 7 h, and finally subjected to enzymatic hydrolysis for 72 h at 52 ℃, with a liquid-solid ratio of 33 and 15 μL/g of β-glycosidase. Under this condition, the enzymatic hydrolysis rates of cellulase and hemicellulase reached 86.65% and 43.9%, respectively. In conclusion, the combination of NaOH and Fenton pretreatment can effectively promote the enzymatic hydrolysis of poplar sawdust, which has great potential in the production of cellulosic ethanol.

2013 ◽  
Vol 411-414 ◽  
pp. 3205-3209
Author(s):  
Fang Qian ◽  
Lei Zhao ◽  
Shu Juan Jiang ◽  
Guang Qing Mu

Based on single factor analysis for the enzymatic hydrolysis of whey protein, papain was selected as the optimal enzyme and its enzymatic hydrolysis conditions were optimized by the quadratic regression orthogonal rotary test. The orthogonal regression model for degree of hydrolysis (DH) to three factors including temperature (X1), time (X2), enzyme dosage (X3) was established as follow: DH=10.40+0.22X1+0.30X2+1.31X3+0.019X1X2+0.011X1X3-0.039X2X3-0.39X12-0.16X22-0.40X32, Verification test showed a DH of 11.7% was obtained at the optimal hydrolysis condition of 56.6°C, 113.8 min and enzyme 8213.7 U /g protein, which basically consisted with the model theoretical value.


Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Fokko Schütt ◽  
Jürgen Puls ◽  
Bodo Saake

Abstract Steam refining was investigated as a pretreatment for enzymatic hydrolysis of poplar wood from a short rotation plantation. The experiments were carried out without debarking to use an economically realistic raw material. Steam refining conditions were varied in the range of 3–30 min and 170–220°C, according to a factorial design created with the software JMP from SAS Institute Inc., Cary, NC, USA. Predicted steaming conditions for highest glucose and xylose yields after enzymatic hydrolysis were at 210°C and 15 min. Control tests under the optimized conditions verified the predicted results. Further pretreatments without bark showed that the enzymes were not significantly inhibited by the bark. The yield of glucose and xylose was 61.9% of theoretical for the experiments with the whole raw material, whereas the yield for the experiments without bark was 63.6%. Alkaline extraction of lignin from the fibers before enzymatic hydrolysis resulted in an increase of glucose yields from mild pretreated fibers and a decrease for severe pretreated fibers. The extracted lignin had a high content of xylose of up to 14% after very mild pretreatments. On the other hand, molecular weights of the extracted lignin increased substantially after pretreatments with a severity factor above 4. Hence, alkaline extraction of the lignin seems only attractive in a narrow range of steaming conditions.


2016 ◽  
Vol 46 (6) ◽  
pp. 778-790 ◽  
Author(s):  
Ghassan Abo Chameh ◽  
Fadi Kheder ◽  
Francois Karabet

Purpose The purpose of this paper was to find out the appropriate enzymatic hydrolysis conditions of alkali pretreated olive pomace (OP) which enable maximum yield of reducing sugar. Design/methodology/approach The commercial enzymatic preparation (Viscozyme® L) was used for the hydrolysis of OP. The effects of pretreatment, time, temperature, pH, enzyme quantity and substrate loading on the hydrolysis yield were investigated. Findings This study showed that enzymatic hydrolysis of OP using Viscozyme® L can be successfully performed at 50°C. Alkaline pretreatment step of OP prior the enzymatic hydrolysis was indispensable. The hydrolysis yield of alkaline pretreated OP was 2.6 times higher than the hydrolysis yield of untreated OP. Highest hydrolysis yield (33.5 ± 1.5 per cent) was achieved after 24 h using 1 per cent (w/v) OP load in the presence of 100 μl Viscozyme® L at 50°C and pH 5.5 with mixing rate of 100 rpm (p = 0.05). Originality/value Reaction time, temperature, pH value and enzyme quantity were found to have a significant effect on enzymatic hydrolysis yield of alkali pretreated of OP. Although high-solid loadings of OP lowered the hydrolysis yield, it produced higher concentration of reducing sugars, which may render the OP conversion process more economically feasible.


2005 ◽  
Vol 277-279 ◽  
pp. 450-454 ◽  
Author(s):  
Young Hee Lee ◽  
Jung Soo Kim ◽  
Han Do Kim

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.


2020 ◽  
Vol 21 (12) ◽  
pp. 1249-1258
Author(s):  
Cindy T. Sepúlveda ◽  
José E. Zapata

Background: Fish is an essential source of nutrients for human nutrition due to the composition of proteins, vitamins, and minerals, among other nutrients. Enzymatic hydrolysis represents an alternative for the use of by-products of the aquaculture industry. Objective: We propose to evaluate the effect of stirring speed, temperature, and initial protein concentration on the degree of hydrolysis of proteins and antioxidant activity of red tilapia (Oreochromis spp.) viscera hydrolysates. Methods: The effect of stirring speed, temperature, and initial protein concentration on the degree of hydrolysis of proteins and antioxidant activity was evaluated using an experimental design that was adjusted to a polynomial equation. The hydrolysate was fractioned to determine the antioxidant activity of the fractions, and functional properties were also measured. Results: Stirring speed and protein concentration presented a statistically significant effect (p <0.05) on all the response variables. However, the temperature did not present a statistically significant effect on the degree of hydrolysis. Discussion: The best conditions of hydrolysis were stirring speed of 51.44 rpm, a temperature of 59.15°C, and the protein concentration of 10 g L-1. The solubility of the hydrolysate protein was high at different pH, and the hydrolysate fraction with the highest antioxidant activity has a molecular weight <1 kDa. Conclusion: The degree of hydrolysis and the biological activity of red tilapia viscera hydrolysates (Oreochromis spp.) are affected by temperature, substrate concentration, and stirring speed. The optimal conditions of hydrolysis allowed to obtain a hydrolysate with antioxidant activity are due to the peptides with low molecular weight.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yanbin Zheng ◽  
Qiushi Chen ◽  
Anshan Shan ◽  
Hao Zhang

For utilizing the blood cells (BCs) effectively, enzymatic hydrolysis was applied to produce the enzymatically hydrolyzed blood cells (EHBCs) by using a neutral protease as a catalyst. The results of the single-factor experiments showed optimal substrate concentration, enzyme to substrate ratio (E/S), pH, temperature, and incubation period were 1.00%, 0.10, 7.00, 50.00°C, and 12.00 h, respectively. The optimized hydrolysis conditions from response surface methodology (RSM) were pH 6.50, E/S 0.11, temperature 45.00°C, and incubation period 12.00 h. Under these conditions (substrate concentration 1.00%), the degree of hydrolysis (DH) was 35.06%. The free amino acids (FAAs) content of the EHBCs (35.24%) was 40.46 times higher than BCs while the total amino acids (TAAs) content was lower than BCs. The scores of lysine (human 0.87; pig 0.97), valine (human 1.42; pig 1.38), leucine (human 1.50; pig 1.90), tyrosine (human 0.84; pig 1.09), and histidine (human 2.17; pig 2.50) indicated that the EHBCs basically fulfilled the adult human and pig nutritional requirements. The calculated protein efficiency ratios (C-PERs) of the EHBCs were 3.94, 6.19, 21.73, and 2.04. In summary, the EHBCs were produced successfully with optimized conditions and could be a novel protein source for humans and pigs.


Food Research ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 153-162
Author(s):  
M.K. Zainol ◽  
F.W. Abdul Sukor ◽  
A. Fisal ◽  
T.C. Tuan Zainazor ◽  
M.R. Abdul Wahab ◽  
...  

This study was aimed to optimise the Alcalase® enzymatic hydrolysis extraction of Asiatic hard clam (AHC) (Meretrix meretrix) protein hydrolysate in terms of hydrolysis time, hydrolysis temperature, hydrolysis pH, and concentration of enzyme. Protein hydrolysate produced from AHC (M. meretrix) meat was used to determine the optimum hydrolysis conditions. Hydrolysis of AHC meat was optimised using the Central Composite Design Response Surface Methodology (RSM) (CCD). The relationship between four parameters such as temperature (45 – 65°C), enzyme to substrate concentration (1 – 2%), hydrolysis time (60 – 180 mins), and pH (7.5 – 9.5) to the degree of hydrolysis was investigated. The optimum conditions for enzymatic hydrolysis of AHC meat to achieve the maximum degree of hydrolysis (DH) were observed at 65°C, enzyme to substrate concentration of 1%, hydrolysis time of 60 mins, and pH 7.5. The enzymatic protein hydrolysis of AHC meat was predicted using a two factors interaction (2FI) model. Under these optimum conditions, DH's predicted value was 97.41%, which was close to the experimental value (97.89%). The freeze-dried protein hydrolysate powder was characterized concerning the proximate composition. Proximate analysis revealed that the AHC meat contains 7.92±1.76% of moisture, 2.23±0.89% of crude fat, 1.98±0.82 of ash, and 10.53±0.04% of crude protein. While the Asiatic hard clam protein hydrolysate (AHCPH) composed 9.12±0.02% of moisture, 0.80±0.29% of crude fat, and 27.76±0.10% of ash. The protein hydrolysate produced also contained high protein content (50.09±0.88%) and may serve as a good protein source.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3653 ◽  
Author(s):  
Robert Balan ◽  
Andrzej Antczak ◽  
Simone Brethauer ◽  
Tomasz Zielenkiewicz ◽  
Michael H. Studer

Steam explosion is a well-known process to pretreat lignocellulosic biomass in order to enhance sugar yields in enzymatic hydrolysis, but pretreatment conditions have to be optimized individually for each material. In this study, we investigated how the results of a pretreatment optimization procedure are influenced by the chosen reaction conditions in the enzymatic hydrolysis. Beechwood was pretreated by steam explosion and the resulting biomass was subjected to enzymatic hydrolysis at glucan loadings of 1% and 5% employing either washed solids or the whole pretreatment slurry. For enzymatic hydrolysis in both reaction modes at a glucan loading of 1%, the glucose yields markedly increased with increasing severity and with increasing pretreatment temperature at identical severities and maximal values were reached at a pretreatment temperature of 230 °C. However, the optimal severity was 5.0 for washed solids enzymatic hydrolysis, but only 4.75 for whole slurry enzymatic hydrolysis. When the glucan loading was increased to 5%, glucose yields hardly increased for pretreatment temperatures between 210 and 230 °C at a given severity, and a pretreatment temperature of 220 °C was sufficient under these conditions. Consequently, it is important to precisely choose the desired conditions of the enzymatic hydrolysis reaction, when aiming to optimize the pretreatment conditions for a certain biomass.


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