scholarly journals A Thermostable Aspergillus fumigatus GH7 Endoglucanase Over-Expressed in Pichia pastoris Stimulates Lignocellulosic Biomass Hydrolysis

2019 ◽  
Vol 20 (9) ◽  
pp. 2261 ◽  
Author(s):  
Aline Vianna Bernardi ◽  
Deborah Kimie Yonamine ◽  
Sergio Akira Uyemura ◽  
Taisa Magnani Dinamarco

In the context of avoiding the use of non-renewable energy sources, employing lignocellulosic biomass for ethanol production remains a challenge. Cellulases play an important role in this scenario: they are some of the most important industrial enzymes that can hydrolyze lignocellulose. This study aims to improve on the characterization of a thermostable Aspergillus fumigatus endo-1,4-β-glucanase GH7 (Af-EGL7). To this end, Af-EGL7 was successfully expressed in Pichia pastoris X-33. The kinetic parameters Km and Vmax were estimated and suggested a robust enzyme. The recombinant protein was highly stable within an extreme pH range (3.0–8.0) and was highly thermostable at 55 °C for 72 h. Low Cu2+ concentrations (0.1–1.0 mM) stimulated Af-EGL7 activity up to 117%. Af-EGL7 was tolerant to inhibition by products, such as glucose and cellobiose. Glucose at 50 mM did not inhibit Af-EGL7 activity, whereas 50 mM cellobiose inhibited Af-EGL7 activity by just 35%. Additionally, the Celluclast® 1.5L cocktail supplemented with Af-EGL7 provided improved hydrolysis of sugarcane bagasse “in natura”, sugarcane exploded bagasse (SEB), corncob, rice straw, and bean straw. In conclusion, the novel characterization of Af-EGL7 conducted in this study highlights the extraordinary properties that make Af-EGL7 a promising candidate for industrial applications.

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Folasade M. Olajuyigbe ◽  
Chidinma M. Nlekerem ◽  
Olusola A. Ogunyewo

Production ofβ-glucosidase fromFusarium oxysporumwas investigated during degradation of some cellulosic substrates (Avicel,α-cellulose, carboxymethyl cellulose (CMC), and methylcellulose). Optimized production ofβ-glucosidase using the cellulosic substrate that supported highest yield of enzyme was examined over 192 h fermentation period and varied pH of 3.0–11.0. Theβ-glucosidase produced was characterized for its suitability for industrial application. Methyl cellulose supported the highest yield ofβ-glucosidase (177.5 U/mg) at pH 6.0 and 30°C at 96 h of fermentation with liberation of 2.121 μmol/mL glucose. The crude enzyme had optimum activity at pH 5.0 and 70°C. The enzyme was stable over broad pH range of 4.0–7.0 with relative residual activity above 60% after 180 min of incubation.β-glucosidase demonstrated high thermostability with 83% of its original activity retained at 70°C after 180 min of incubation. The activity ofβ-glucosidase was enhanced by Mn2+and Fe2+with relative activities of 167.67% and 205.56%, respectively, at 5 mM and 360% and 315%, respectively, at 10 mM. The properties shown byβ-glucosidase suggest suitability of the enzyme for industrial applications in the improvement of hydrolysis of cellulosic compounds into fermentable sugars that can be used in energy generation and biofuel production.


Author(s):  
Thomas Bessonnet ◽  
Aline Mariage ◽  
Jean-Louis Petit ◽  
Virginie Pellouin ◽  
Adrien Debard ◽  
...  

Despite the success of some nitrilases in industrial applications, there is a constant demand to broaden the catalog of these hydrolases, especially robust ones with high operational stability. By using the criteria of thermoresistance to screen a collection of candidate enzymes heterologously expressed in Escherichia coli, the enzyme Nitphym from the mesophilic organism Paraburkholderia phymatum was selected and further characterized. Its quick and efficient purification by heat treatment is of major interest for large-scale applications. The purified nitrilase displayed a high thermostability with 90% of remaining activity after 2 days at 30°C and a half-life of 18 h at 60°C, together with a broad pH range of 5.5–8.5. Its high resistance to various miscible cosolvents and tolerance to high substrate loadings enabled the quantitative conversion of 65.5 g⋅L–1 of 3-phenylpropionitrile into 3-phenylpropionic acid at 50°C in 8 h at low enzyme loadings of 0.5 g⋅L–1, with an isolated yield of 90%. This study highlights that thermophilic organisms are not the only source of industrially relevant thermostable enzymes and extends the scope of efficient nitrilases for the hydrolysis of a wide range of nitriles, especially trans-cinnamonitrile, terephthalonitrile, cyanopyridines, and 3-phenylpropionitrile.


2000 ◽  
Vol 66 (1) ◽  
pp. 252-256 ◽  
Author(s):  
Katsuichi Saito ◽  
Kazuya Kondo ◽  
Ichiro Kojima ◽  
Atsushi Yokota ◽  
Fusao Tomita

ABSTRACT Streptomyces exfoliatus F3-2 produced an extracellular enzyme that converted levan, a β-2,6-linked fructan, into levanbiose. The enzyme was purified 50-fold from culture supernatant to give a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights of this enzyme were 54,000 by SDS-PAGE and 60,000 by gel filtration, suggesting the monomeric structure of the enzyme. The isoelectric point of the enzyme was determined to be 4.7. The optimal pH and temperature of the enzyme for levan degradation were pH 5.5 and 60°C, respectively. The enzyme was stable in the pH range 3.5 to 8.0 and also up to 50°C. The enzyme gave levanbiose as a major degradation product from levan in an exo-acting manner. It was also found that this enzyme catalyzed hydrolysis of such fructooligosaccharides as 1-kestose, nystose, and 1-fructosylnystose by liberating fructose. Thus, this enzyme appeared to hydrolyze not only β-2,6-linkage of levan, but also β-2,1-linkage of fructooligosaccharides. From these data, the enzyme from S. exfoliatus F3-2 was identified as a novel 2,6-β-d-fructan 6-levanbiohydrolase (EC 3.2.1.64 ).


Marine Drugs ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 416
Author(s):  
Yan Ma ◽  
Jie Li ◽  
Xin-Yue Zhang ◽  
Hao-Dong Ni ◽  
Feng-Biao Wang ◽  
...  

Alginate lyases play an important role in alginate oligosaccharides (AOS) preparation and brown seaweed processing. Many extracellular alginate lyases have been characterized to develop efficient degradation tools needed for industrial applications. However, few studies focusing on intracellular alginate lyases have been conducted. In this work, a novel intracellular alkaline alginate lyase Alyw202 from Vibrio sp. W2 was cloned, expressed and characterized. Secretory expression was performed in a food-grade host, Yarrowia lipolytica. Recombinant Alyw202 with a molecular weight of approximately 38.3 kDa exhibited the highest activity at 45 °C and more than 60% of the activity in a broad pH range of 3.0 to 10.0. Furthermore, Alyw202 showed remarkable metal ion-tolerance, NaCl independence and the capacity of degrading alginate into oligosaccharides of DP2-DP4. Due to the unique pH-stable and high salt-tolerant properties, Alyw202 has potential applications in the food and pharmaceutical industries.


2008 ◽  
Vol 53 (2) ◽  
pp. 557-562 ◽  
Author(s):  
Daniel J. Wolter ◽  
Philip M. Kurpiel ◽  
Neil Woodford ◽  
Marie-France I. Palepou ◽  
Richard V. Goering ◽  
...  

ABSTRACT A novel Klebsiella pneumoniae carbapenemase (KPC) variant, designated bla KPC-5, was discovered in a carbapenem-resistant Pseudomonas aeruginosa clinical isolate from Puerto Rico. Characterization of the upstream region of bla KPC-5 showed significant differences from the flanking regions of other bla KPC variants. Comparison of amino acid sequences with those of other KPC enzymes revealed that KPC-5 was an intermediate between KPC-2 and KPC-4, differing from KPC-2 by a single amino acid substitution (Pro103→Arg), while KPC-4 contained Pro103→Arg plus an additional amino acid change (Val239→Gly). Transformation studies with an Escherichia coli recipient strain showed differences in the properties of the KPC variants. KPC-4 and KPC-5 both had pIs of 7.65, in contrast with the pI of 6.7 for KPC-2. KPC-2 transformants were less susceptible to the carbapenems than KPC-4 and KPC-5 transformants. These data correlated with higher rates of imipenem hydrolysis for KPC-2 than for KPC-4 and KPC-5. However, KPC-4 and KPC-5 transformants had higher ceftazidime MICs, and the enzymes from these transformants had slightly better hydrolysis of this drug than KPC-2. KPC-4 and KPC-5 were more sensitive than KPC-2 to inhibition by clavulanic acid in both susceptibility testing and hydrolysis assays. Thus, KPC enzymes may be evolving through stepwise mutations to alter their spectra of activity.


2017 ◽  
Vol 18 (02) ◽  
pp. 103-108
Author(s):  
Vivitri Dewi Prasasty ◽  
Vinella Winata ◽  
Muhammad Hanafi

Lipases are known as glycerol ester hydrolases that catalyze the hydrolysis of triglycerides into free fatty acids and glycerol. Lipases are found in human, animal, plant, and microorganisms. The aim of this research is to identify lipase producers and characterize bacterial lipase from West Java plateau soil. Plateau soil bacteria samples were isolated on lipase screening medium containing Rhodamine B. Olive oil was used as a substrate in screening and production medium bacterial lipases. From 16 bacterial isolate of lipase producers, 14 were identified as Bacillus sp. and the others were identified as Pseudomonas alcaligenes. All isolates were taken into production step to determine their lipase activities. Moreover, top 3 lipase activities out of 16 lipase activities were chosen to find the optimum pH and temperature. Both characterizations showed pH optimum and temperature optimum from each lipase. These optimum condition were used in heat stability characterization for each lipase samples. The result showed that lipase from isolate COK 2 in optimum pH 4 and temperature 50oC was the most stable lipase due to this sample has good and stable activity for 1 to 5 hours incubation time. Lipase sample from isolate COK 2 has good efficiency for lipase productivity in acid condition and high temperature. Results of this investigation could encourage utilization of these activity enhancers for various industrial applications.


Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Eugenio Brusa ◽  
Cristiana Delprete ◽  
Lorenzo Giorio ◽  
Luigi Gianpio Di Maggio ◽  
Vittorio Zanella

The remote prognosis and diagnosis of bearings can prevent industrial system failures, but the availability of realistic experimental data, being as close as possible to those detected in industrial applications, is essential to validate the monitoring algorithms. In this paper, an innovative bearing test rig architecture is presented, based on the novel concept of “self-contained box”. The monitoring activity is applicable to a set of four middle-sized bearings simultaneously, while undergoing the independent application of radial and axial loads in order to simulate the behavior of the real industrial machinery. The impact of actions on the platform and supports is mitigated by the so-called “self-contained box” layout, leading to self-balancing of actions within the rotor system. Moreover, the high modularity of this innovative layout allows installing various sized bearings, just changing mechanical adapters. This leads to a reduction of cost as well as of system down-time required to change bearings. The test rig is equipped with suitable instrumentation to develop effective procedures and tools for in- and out-monitoring of the system. An initial characterization of the healthy system is presented.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qiuling Zheng ◽  
Xiangjun Meng ◽  
Mingyang Cheng ◽  
Yanfeng Li ◽  
Yuanpeng Liu ◽  
...  

Chitosanase is a significant chitosan-degrading enzyme involved in industrial applications, which forms chitooligosaccharides (COS) as reaction products that are known to have various biological activities. In this study, the gene csnS was cloned from a deep-sea bacterium Serratia sp. QD07, as well as over-expressed in Escherichia coli, which is a new chitosanase encoding gene. The recombinant strain was cultured in a 5 L fermenter, which yielded 324 U/mL chitosanases. After purification, CsnS is a cold-adapted enzyme with the highest activity at 60°C, showing 37.5% of the maximal activity at 0°C and 42.6% of the maximal activity at 10°C. It exhibited optimum activity at pH 5.8 and was stable at a pH range of 3.4–8.8. Additionally, CsnS exhibited an endo-type cleavage pattern and hydrolyzed chitosan polymers to yield disaccharides and trisaccharides as the primary reaction products. These results make CsnS a potential candidate for the industrial manufacture of COS.


Marine Drugs ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 312 ◽  
Author(s):  
Dandan Li ◽  
Shangyong Li ◽  
Yanhong Wu ◽  
Mengfei Jin ◽  
Yu Zhou ◽  
...  

As prebiotics, galacto-oligosaccharides (GOSs) can improve the intestinal flora and have important applications in medicine. β-galactosidases could promote the synthesis of GOSs in lactose and catalyze the hydrolysis of lactose. In this study, a new β-galactosidase gene (gal2A), which belongs to the glycoside hydrolase family 2, was cloned from marine bacterium Alteromonas sp. QD01 and expressed in Escherichia coli. The molecular weight of Gal2A was 117.07 kDa. The optimal pH and temperature of Gal2A were 8.0 and 40 °C, respectively. At the same time, Gal2A showed wide pH stability in the pH range of 6.0–9.5, which is suitable for lactose hydrolysis in milk. Most metal ions promoted the activity of Gal2A, especially Mn2+ and Mg2+. Importantly, Gal2A exhibited high transglycosylation activity, which can catalyze the formation of GOS from milk and lactose. These characteristics indicated that Gal2A may be ideal for producing GOSs and lactose-reducing dairy products.


2014 ◽  
Vol 16 (11) ◽  
pp. 4659-4662 ◽  
Author(s):  
Max A. Mellmer ◽  
David Martin Alonso ◽  
Jeremy S. Luterbacher ◽  
Jean Marcel R. Gallo ◽  
James A. Dumesic

The use of γ-valerolactone as solvent for acid-catalyzed biomass hydrolysis reactions increases reaction rates compared to reactions carried out in water.


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