scholarly journals Production of Sugar Feedstocks for Fermentation Processes from Selected Fast Growing Grasses

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3129 ◽  
Author(s):  
Kamila Przybysz ◽  
Edyta Małachowska ◽  
Danuta Martyniak ◽  
Piotr Boruszewski ◽  
Halina Kalinowska ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Kraft Pulping ◽  
Cellulose Content ◽  
Potential Yield ◽  
Fermentation Processes ◽  
Fast Growing ◽  
Initial Substrate ◽  
Scientific Goal ◽  
Hydrolysis Of ◽  
Substrate Concentrations

This study showed that kraft cellulosic pulps from Miscanthus giganetus JM Greef and Deuter ex Hodk. and Renvoize, sweet sorghum and 5 other fast growing grasses may be easily enzymatically converted to glucose-rich sugar feedstocks. The scientific goal of the paper was to assess and compare the potential yield of hydrolysis and verify whether these grasses may be a source of sugars for fermentation processes. Kraft pulping was used as a pretreatment method and hydrolysis of the pulps was conducted using a commercial multienzyme preparation containing cellulases and xylanases at initial substrate concentrations of 0.476, 3.88 and 7.46% w/v, and 3 different enzyme loadings. Results showed that tall wheatgrass, striped tuber oat grass, tall fescue and smooth bromegrass may be efficiently converted to sugar feedstocks for biotechnology application, but that the simple reducing sugars yield is lower than for wood, due to lower cellulose content.

Phosphorus Release Kinetics in Biofilm Reactors

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza
Keyword(s):  
Phosphorus Removal ◽  
Release Kinetics ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biofilm Reactor ◽  
Substrate Uptake ◽  
Biofilm Reactors ◽  
Initial Substrate ◽  
Linear Behaviour ◽  
Substrate Concentrations

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.

Enhanced Hydrolysis of Cellulose to Reducing Sugars on Kaolinte Clay Activated by Mineral Acid

2021 ◽  
Author(s):  
Yuxiao Dong ◽  
Dongshen Tong ◽  
Laibin Ren ◽  
Xingtao Chen ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Mineral Acid ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Base-catalyzed Degradations of Carbohydrates. IX. β-Eliminations of 4-O-Substituted Hexopyranosiduronates

1975 ◽  
Vol 53 (14) ◽  
pp. 2182-2188 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Thinnayam N. Krishnamurthy ◽  
Walter Mitura ◽  
Masuo Funabashi
Keyword(s):  
Acid Hydrolysis ◽  
Reducing Sugars ◽  
Model Compounds ◽  
Methyl Methyl ◽  
Hydrolysis Of

Two methylated disaccharides, methyl [methyl 4-O-(2,3,4,6-tetra-O-methyl-α-D-glucopyranosyl)-2,3-di-O-methyl-β-D-glucopyranosid]uronate (9) and methyl 6-O-(methyl 2,3,4-tri-O-methyl-α-D-galactopyranosyluronate)-2,3,4-tri-O-methyl-β-D-glucopyranoside (15) have been synthesized and used as model compounds for the study of the base-catalyzed β-elimination of 4-O-substituted hexopyranosiduronates without degradation of exposed reducing sugars and of the selective acid hydrolysis of hex-4-enopyranosiduronates.

pH Effects in trypsin catalysis

1969 ◽  
Vol 47 (21) ◽  
pp. 4021-4029 ◽  
Author(s):  
H. P. Kasserra ◽  
K. J. Laidler
Keyword(s):  
Complex Formation ◽  
Ph Dependence ◽  
Specific Rotation ◽  
Ph Effects ◽  
Ph Values ◽  
A Value ◽  
Available Information ◽  
Hydrolysis Of ◽  
Substrate Concentrations ◽  
Covalent Complex

A kinetic study has been made of the trypsin-catalyzed hydrolysis of N-benzoyl-L-alanine methyl ester, at pH values ranging from 6 to 10. The substrate concentrations varied from 1.7 × 10−3 to 4.3 × 10−2 M. From the rates were calculated, at each pH, values of [Formula: see text] (corresponding to [Formula: see text]), [Formula: see text] (corresponding to [Formula: see text]) and [Formula: see text] The specific levorotation of trypsin was measured and found to vary with pH in the pH region 5–11, the change in specific rotation following the ionization of a single group with pK(app) of 9.4. At pH 11 the specific rotation of trypsin, its zymogen, and its phosphorylated derivative were approximately the same, suggesting similar conformations for all three forms of the protein.The kinetic results on the acid side were very similar to those obtained by other investigators for chymotrypsin; they imply that there is a group of [Formula: see text] in the free enzyme, presumably the imidazole function of a histidine residue, and that this group is involved in acylation and deacylation, which can only occur if it is unprotonated. The behavior on the basic side was found to be different from that with chymotrypsin revealing a decrease in [Formula: see text] at high pH corresponding to a value of [Formula: see text] whereas [Formula: see text] showed sigmoid pH-dependence. An interpretation of these results that is consistent with all available information is that a group of [Formula: see text] (presumably the —NH3+ function of the terminal isoleucine) controls the conformation and thereby the activity of the enzyme at different stages of complex formation. In contrast to chymotrypsin, the pK of this ionizing group appears to be generally lowered by covalent complex formation between trypsin and its substrates.

scholarly journals Kinetics of Enzymatic Hydrolysis of Southeast Sulawesi Sago Starch

2020 ◽  
pp. 53-61
Author(s):  
Ansharullah Ansharullah ◽  
Muhammad Natsir
Keyword(s):  
Enzymatic Hydrolysis ◽  
Maximum Velocity ◽  
Enzyme Concentration ◽  
Hydrolysis Rate ◽  
Sago Starch ◽  
Optimum Conditions ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Substrate Concentrations ◽  
Menten Constant

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.

Valorization of agro-industrial wastes to produce hydrolytic enzymes by fungal solid-state fermentation

2018 ◽  
Vol 37 (2) ◽  
pp. 149-156 ◽  
Author(s):  
C. Marzo ◽  
A.B. Díaz ◽  
I. Caro ◽  
A. Blandino
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Reducing Sugars ◽  
Raw Materials ◽  
Hydrolytic Enzymes ◽  
Industrial Wastes ◽  
Added Value ◽  
Orange Peels ◽  
Enzyme Cocktail ◽  
Hydrolysis Of

Nowadays, significant amounts of agro-industrial wastes are discarded by industries; however, they represent interesting raw materials for the production of high-added value products. In this regard, orange peels (ORA) and exhausted sugar beet cossettes (ESBC) have turned out to be promising raw materials for hydrolytic enzymes production by solid state fermentation (SSF) and also a source of sugars which could be fermented to different high-added value products. The maximum activities of xylanase and exo-polygalacturonase (exo-PG) measured in the enzymatic extracts obtained after the SSF of ORA were 31,000 U·kg-1 and 17,600 U·kg-1, respectively; while for ESBC the maximum values reached were 35,000 U·kg-1 and 28,000 U·kg-1, respectively. The enzymatic extracts obtained in the SSF experiments were also employed for the hydrolysis of ORA and ESBC. Furthermore, it was found that extracts obtained from SSF of ORA, supplemented with commercial cellulase, were more efficient for the hydrolysis of ORA and ESBC than a commercial enzyme cocktail typically used for this purpose. In this case, maximum reducing sugars concentrations of 57 and 47 g·L-1 were measured after the enzymatic hydrolysis of ESBC and ORA, respectively.

Effective Substrate Loading for Saccharification of Corn Cob and Concurrent Production of Lignocellulolytic Enzymes by Fusarium oxysporum and Sporothrix carnis

2020 ◽  
Vol 8 (2) ◽  
pp. 109-115
Author(s):  
Folasade M. Olajuyigbe ◽  
Cornelius O. Fatokun ◽  
Oluwatosin I. Oni
Keyword(s):  
Fusarium Oxysporum ◽  
Substrate Concentration ◽  
Reducing Sugars ◽  
Cost Effective ◽  
Reducing Sugar ◽  
Lignocellulolytic Enzymes ◽  
Corn Cob ◽  
Lignocellulosic Wastes ◽  
Single Process ◽  
Substrate Concentrations

Background: One of the critical challenges of cost-effective bioethanol production from lignocellulosic biomass is the decreasing yield of reducing sugars caused by increasing substrate loading. Hence, it is crucial to determine the best substrate concentration for efficient saccharification of lignocellulosic wastes. Objective: This paper reports the saccharification of corn cob by two lignocellulolytic fungi (Fusarium oxysporum and Sporothrix carnis) and concurrent production of lignocellulolytic enzymes at varying substrate concentrations. Methods: F. oxysporum and S. carnis were cultivated on corn cob based media at 30°C and 160 rpm for 144 h. The lignocellulosic composition of corn cob was determined. Saccharification of varying concentrations of substrate was determined by evaluating the release of reducing sugar while the production of cellulase and xylanase was monitored. Results: Cellulose, hemicellulose and lignin contents of corn cob were 37.8±1.56%, 42.2±1.68% and 12.7±1.23%, respectively. Yields of reducing sugar by F. oxysporum and S. carnis were 5.03 µmol/mL and 6.16 µmol/mL; and 6.26 µmol/mL and 6.58 μmol/mL at 10.0 and 25.0% substrate concentration, respectively. The production of cellulase and xylanase was exponential as corn cob concentration increased from 0.5% to 10.0% yielding 586.93 U/mL and 1559.18 U/mL from F. oxysporum, with 590.7 U/mL and 1573.95 U/mL from S. carnis, respectively. Conclusion: The study shows that the most efficient saccharification of corn cob by F. oxysporum and S. carnis was achieved at 10.0% substrate concentration. This suggests that two separate saccharification processes at this concentration will result in higher yields of enzyme and reducing sugars than a single process involving higher concentration.

scholarly journals Enzymatic sugar production from elephant grass and reed straw through pretreatments and hydrolysis with addition of thioredoxin-His-S

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xianqin Lu ◽  
Can Li ◽  
Shengkui Zhang ◽  
Xiaohan Wang ◽  
Wenqing Zhang ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Pennisetum Purpureum ◽  
Commercial Application ◽  
Hydrolysis Lignin ◽  
Cellulose Content ◽  
Sugar Production ◽  
Elephant Grass ◽  
Reed Straw ◽  
Hydrolysis Yield ◽  
Hydrolysis Of

Abstract Background The bioconversion of lignocellulose to fermentable C5/C6-saccharides is composed of pretreatment and enzymatic hydrolysis. Lignin, as one of the main components, resists lignocellulose to be bio-digested. Alkali and organosolv treatments were reported to be able to delignify feedstocks and loose lignocellulose structure. In addition, the use of additives was an alternative way to block lignin and reduce the binding of cellulases to lignin during hydrolysis. However, the relatively high cost of these additives limits their commercial application. Results This study explored the feasibility of using elephant grass (Pennisetum purpureum) and reed straw (Phragmites australis), both of which are important fibrous plants with high biomass, no-occupation of cultivated land, and soil phytoremediation, as feedstocks for bio-saccharification. Compared with typical agricultural residues, elephant grass and reed straw contained high contents of cellulose and hemicellulose. However, lignin droplets on the surface of elephant grass and the high lignin content in reed straw limited their hydrolysis performances. High hydrolysis yield was obtained for reed straw after organosolv and alkali pretreatments via increasing cellulose content and removing lignin. However, the hydrolysis of elephant grass was only enhanced by organosolv pretreatment. Further study showed that the addition of bovine serum albumin (BSA) or thioredoxin with His- and S-Tags (Trx-His-S) improved the hydrolysis of alkali-pretreated elephant grass. In particular, Trx-His-S was first used as an additive in lignocellulose saccharification. Its structural and catalytic properties were supposed to be beneficial for enzymatic hydrolysis. Conclusions Elephant grass and reed straw could be used as feedstocks for bioconversion. Organosolv and alkali pretreatments improved their enzymatic sugar production; however, the increase in hydrolysis yield of pretreated elephant grass was not as effective as that of reed straw. During the hydrolysis of alkali-pretreated elephant grass, Trx-His-S performed well as additive, and its structural and catalytic capability was beneficial for enzymatic hydrolysis.

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