Combination effect of pH and acetate on enzymatic cellulose hydrolysis (original) (raw)
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Optimization of Cellulolytic Bacteria from Cellulose Waste Materials and its Activity
Cellulases are the group of hydrolytic enzymes and they are capable of degrading all types of cellulosic waste materials. Present study focuses on the isolation, screening and enzymatic hydrolysis cellulolytic bacteria from various agricultural wastes under submerged fermentation and optimization of pH, temperature, carbon and nitrogen sources for the activity of enzyme production was tested. The enzyme reaction was carried out by CMC (Carboxy methyl cellulose) and the production was analyzed individually by Miller‘s modified method of Dinitro-salicylic acid (DNS). The cellulase producing bacteria was identified as Bacillus sp from Tapioca leaf, Pseudomonas aeroginosa from sugarcane Bagassee, Pseudomonas flourescens from Bamboo leaf, Cellulomonas sp from Sweet lemon peel, Micrococcus sp from Tapioca shell, Streptococcus sp from Turmeric leaf and Lactobacillus sp from Groundnut shell etc are the isolates shown a good results. Seven different bacterial strains were isolated and screened for cellulase production in submerged fermentation process. Among these seven tested bacterial strains; Bacillus sp secretes maximum amount of cellulose production around 7.896(IU/ml) under a submerged fermentation. The optimum pH and temperature for the activity of enzyme was 7 and 50°C and acetate as carbon source and ammonium sulfate as nitrogen source respectively. Keywords: Agricultural waste, Cellulases, Cellulase producing bacteria, CMC (carboxymethylcellulose).
Biotechnology and Bioengineering, 1987
The process of enzymatic cellulose saccharification has been widely investigated recently since cellulose is the most abundant renewable resource and glucose formed as a product of hydrolysis can be converted to ethanol, microbial products, and other chemicals. The efficiency of enzymatic cellulose hydrolysis is known to be affected by many factors related to the source of the cellulase preparation,14 composition and structure of cellulosic material, the method of its pretreatment,'-1° process conditions,"I2 and the reactor design.'",." Since these factors are closely interrelated, a complex study of hydrolysis and a quantitative estimation of the role of the individual factors affecting its efficiency are needed to optimize the process.
Enhancement of solubilization rate of cellulose in anaerobic digestion and its drawbacks
Process Biochemistry, 2011
Hydrolysis is widely acknowledged as the rate-limiting step in anaerobic digestion of solid cellulose to biogas (methane), and pretreatment is generally considered to facilitate the process. However, few studies have investigated how such pretreatment may affect the rest of this complex process. The present study compared the solubilization rate in anaerobic digestion of cotton linter (high crystalline cellulose), with that of regenerated cellulose (amorphous cellulose), using pretreatment with NMMO. Batch digestions were performed, with the initial cellulose concentrations ranging between 5 and 40 g/l, and during 30 days of incubation, biogas and VFAs production as well as pH and COD changes were measured. The lag time before digestion started was longer for the high crystalline cellulose than for the amorphous one. The maximum solubilization rates of treated cellulose were 842 and 517 mg sCOD/g cCOD/day at the initial cellulose concentration of 5 and 30 g/l, respectively, while the solubilization rate of untreated cellulose never exceeded 417 mg sCOD/g cCOD/day. The difference between the two cellulose types was a direct result of the high rate of hydrolysis inhibiting the acetogenesis/methanogenesis microorganisms, a drawback to the rest of the process.
Cellulose from Brewers Spent Grain (BSG) and crystalline cellulose were utilized as sole carbon source for the submerged production of Cellulase. A total of 21 bacterial isolates were obtained from Brewers Spent Grain undergoing deterioration. Out of the 21 isolates, 7 bacterial isolates showed various degrees of Cellulase production on plate assay (Nutrient Agar +2% (W/V) Cellulose) by their zones of clearance of Cellulose. The Brewers Spent Grain was characterized for its composition, and its moisture content, Crude Fibre, Fat, Protein, Ash and Total carbohydrate were 17.62%, 13.94%, 8.08%, 25%, 3.68% and 31.68% respectively. Cellulase production screening of bacterial isolates showed that Bacillus species strain B223 had the highest zone of clearance (2.8cm ± 0.02), and was used for the submerged Cellulase production. Microbial population dynamics in the enzyme production medium in the 250ml capacity Erlenmeyer flasks containing BSG cellulose increased progressively from zero hour to the 120 hour. pH of the BSG cellulose medium increased from 5.28 to 6.89, while the setup containing crystalline cellulose had its pH increased from 5.28 to 7.46. Crude cellulase activity of the cellulase in Filter paper Units (FPU) for the cellulase produced from BSG Cellullose ranged from 328 FPU, 2749PU, 32166FPU, 31910 FPU, and 33130 FPU at zero hour, 24hour, 48hour, 72 hour, 96 hour and 120 hour of fermentation respectively. The optimum pH for the production of Cellulase was 6.89. Specific Cellulase activities of Cellulase produced using BSG cellulose and Crystalline cellulose were between 12.45-4319.4 (Unit/Mg) and 19.6-5711 (Unit/Mg) respectively. Cellulases are industrial enzymes with broad applications, and production using raw materials like cellulose from Brewers Spent Grain makes the enzyme cost effective, and converts the waste (BSG) to wealth. Further research actions are ongoing to purify the crude Cellulase.
The effect of enzyme concentration on the rate of the hydrolysis of cellulose
Biotechnology and Bioengineering, 1989
The relationship among extent of hydrolysis, reaction time, and enzyme dosage was investigated. For this, Sigmacell 50 and pretreated poplar wood (20 g/L) was hydrolyzed with varying dosages of cellulases from three different sources (5 to 100 FPU/g) for time periods ranging from 2 to 94 h. It was found that the formation of glucose can be described by summation of two parallel first order reactions. The extent of hydrolysis at fixed time increases with increasing enzyme dosage in a hyperbolic function. From the empirical data it is possible to calculate the fractions of easily and difficult hydrolyzable cellulose and the digestability which could maximally be obtained at infinite enzyme loadings. In the system Sigmacell 50 and Celluclast the easily and difficult hydrolyzable components are 43.0 and 57.0%, respectively, and the maximum digestability at 94 h i s 82.6%. Poplar wood, steam treated at 200°, 220", and 240°C, showed with Celluclast at 24 h a maximum digestability (weight percentage of wood degraded to glucose) of 43.9, 64.9, and 68.0%. The relationships derived from experimental data allow one to compare objectively the effectiveness of different cellulase enzymes and different pretreatments.
Advances in Bioscience and Biotechnology, 2016
The properties of extracellular cellulase obtained from Bacillus species (FIIRO Strain B223) on supplying cellulose from Brewers Spent Grain (BSG) were studied. Generally, a crude cellulase activity between 11,757 Units to 13,930 Units was observed for both sources of carbon (BSG and crystalline cellulose). The optimum pH and temperature of 5.0, and 30˚C-40˚C for both sources of carbon was observed. Heavy metals such as copper, zinc, and iron inhibited the activities of B223 cellulase while the cellulase activities on alkaline earth metal (manganese) were moderate. The co-factor behaviour of manganese ion was also established. Local production of cellulase in Nigeria using local raw materials such as Brewers Spent Grain reduces enzyme cost; cost of finished products and increases gross domestic products.
Production of Cellulases by Bacillus cellulosilyticus Using Lignocellulosic Material
Polish Journal of Environmental Studies
Cellulases are the most useful enzymes in industry. They can be produced by fungi, bacteria, or actinomycetes. The high cost of cellulases is mainly due to the substrates used in production, and also the slow growth rate of fungi. Most of the research on cellulase production has focused on fungi, with relatively lesser stress on bacteria [1]. Bacteria, which have high growth rates compared to fungi, have good potential to be used in cellulase production [2]. Also, bacteria, owing to their diversity and rapid growth, can produce both alkalistable and temperature-stable enzymes, which can be very important from an industrial point of view [3]. Cellulases produced by bacteria are often more effective catalysts. They may also be less inhibited by the presence of material that has already been hydrolyzed (feedback inhibition) [2]. Bacillus cellulosilyticus, Alkaliphilic Bacillus species has important industrial applications due to its ability to produce alkaline enzymes such as cellulase [4]. It produced extracellular enzymes that are resistant to high pH and high temperature conditions [4-6]. Cellulose, hemicelluloses, and lignin are major components of the lignocellulosic biomass. Cellulose binds tightly with lignin and hemicellulose. For efficient hydrolysis of cellulose, lignin components must be separated in order to make cellulose more accessible to the enzymes [7]. Prior to enzymatic hydrolysis, pretreatment is an important tool for practical cellulose
The goal of this work was to clone, express, characterize and assemble a set of soluble thermostable cellulases capable of significantly degrading cellulose. We successfully cloned, expressed, and purified eleven Clostridium thermocellum (Cthe) cellulases and eight Acidothermus cellulolyticus (Acel) cellulases. The performance of the nineteen enzymes was evaluated on crystalline (filter paper) and amorphous (PASC) cellulose. Hydrolysis products generated from these two substrates were converted to glucose using beta-glucosidase and the glucose formed was determined enzymatically. Ten of the eleven Cthe enzymes were highly active on amorphous cellulose. The individual enzymes all produced <10% reducing sugar equivalents from filter paper. Combinations of Cthe cellulases gave higher conversions, with the combination of CelE, CelI, CelG, and CelK converting 34% of the crystalline cellulose. All eight Acel cellulases showed endo-cellulase activity and were highly active on PASC. Only Acel_0615 produced more than 10% reducing sugar equivalents from filter paper, and a combination of six Acel cellulases produced 32% conversion. Acel_0617, a GH48 exo-cellulase, and Acel_0619, a GH12 endo-cellulase, synergistically stimulated cellulose degradation by the combination of Cthe cellulases to almost 80%. Addition of both Acel enzymes to the Cthe enzyme mix did not further stimulate hydrolysis. Cthe CelG and CelI stimulated cellulose degradation by the combination of Acel cellulases to 66%.
Advances in Bioscience and Biotechnology, 2016
The properties of extracellular cellulase obtained from Bacillus species (FIIRO Strain B223) on supplying cellulose from Brewers Spent Grain (BSG) were studied. Generally, a crude cellulase activity between 11,757 Units to 13,930 Units was observed for both sources of carbon (BSG and crystalline cellulose). The optimum pH and temperature of 5.0, and 30˚C-40˚C for both sources of carbon was observed. Heavy metals such as copper, zinc, and iron inhibited the activities of B223 cellulase while the cellulase activities on alkaline earth metal (manganese) were moderate. The co-factor behaviour of manganese ion was also established. Local production of cellulase in Nigeria using local raw materials such as Brewers Spent Grain reduces enzyme cost; cost of finished products and increases gross domestic products.
R Production of bacterial cellulose and enzyme from waste fiber sludge
Background: Bacterial cellulose (BC) is a highly crystalline and mechanically stable nanopolymer, which has excellent potential as a material in many novel applications, especially if it can be produced in large amounts from an inexpensive feedstock. Waste fiber sludge, a residue with little or no value, originates from pulp mills and lignocellulosic biorefineries. A high cellulose and low lignin content contributes to making the fiber sludge suitable for bioconversion, even without a thermochemical pretreatment step. In this study, the possibility to combine production of BC and hydrolytic enzymes from fiber sludge was investigated. The BC was characterized using field-emission scanning electron microscopy and X-ray diffraction analysis, and its mechanical properties were investigated. Results: Bacterial cellulose and enzymes were produced through sequential fermentations with the bacterium Gluconacetobacter xylinus and the filamentous fungus Trichoderma reesei. Fiber sludges from sulfate (SAFS) and sulfite (SIFS) processes were hydrolyzed enzymatically without prior thermochemical pretreatment and the resulting hydrolysates were used for BC production. The highest volumetric yields of BC from SAFS and SIFS were 11 and 10 g/L (DW), respectively. The BC yield on initial sugar in hydrolysate-based medium reached 0.3 g/g after seven days of cultivation. The tensile strength of wet BC from hydrolysate medium was about 0.04 MPa compared to about 0.03 MPa for BC from a glucose-based reference medium, while the crystallinity was slightly lower for BC from hydrolysate cultures. The spent hydrolysates were used for production of cellulase with T. reesei. The cellulase activity (CMCase activity) in spent SAFS and SIFS hydrolysates reached 5.2 U/mL (87 nkat/mL), which was similar to the activity level obtained in a reference medium containing equal amounts of reducing sugar.