OPTIMIZATION OF LACCASE PRODUCTION BY CURVULARIA LUNATA USING MAIZE COB AS SUBSTRATE

2021 ◽  
Vol 4 (4) ◽  
pp. 460-468
Author(s):  
A. Bello ◽  
D. A. Machido ◽  
A. I. Mohammed-Dabo ◽  
S. A. Ado

Researchers are showing interest in laccase because it is able to degrade several lignocellulosic biomass. It is important to optimize laccase production to achieve higher yield at a lower cost using agricultural wastes. This study was aimed at optimizing the culture conditions for laccase production. Previously isolated and characterized laccase producing Curvularia lunata was collected from the laboratory of Microbiology department, ABU, Zaria. Maize cobs which were used as substrate were collected from Seed Processing Unit of Institute for Agricultural Research, Zaria and the proximate composition of the substrate was determined according to AOAC guideline. The optimum fermentation type for laccase production was determined after which the culture conditions for laccase production were optimized. Laccase activity was determination by guaiacol assay. The proximate compositions of the maize cob were found to be Moisture content (3.18%), Crude protein (2.50%), Crude fat (32.20%), Crude fibre (3.15), Ash content (1.88%) and Carbohydrate content (57.09%). Higher laccase activity was recorded under solid state fermentation compared to submerged fermentation. The optimum culture conditions were found to be inoculum size 3 x 5 mm, pH 5, incubation temperature 30 oC and incubation period of 6 days. The culture conditions for laccase production by Curvularia lunata using maize cob as substrate were optimized

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9166-9179
Author(s):  
Qi An ◽  
Jie Qiao ◽  
Lu-Sen Bian ◽  
Mei-Ling Han ◽  
Xun-You Yan ◽  
...  

Different Pleurotus ostreatus and Flammulina velutipes species were compared relative to their ability to produce laccase in submerged fermentation of various lignocellulosic wastes. Fungi cultivation in identical culture conditions revealed wide differences among both species and strains of the same species. The laccase secretion ability of P. ostreatus strains was superior to F. velutipes strains. Maximum laccase production on cottonseed hull, corncob, and poplar wood was secreted by P. ostreatus CY 568, P. ostreatus CCEF 89, and P. ostreatus CY 568, respectively. The nature of lignocellulosic materials played an important role in determining the expression of laccase potential of fungi. The presence of cottonseed hull improved laccase activity and accelerated the rate of enzyme production. Maximum laccase production on cottonseed hull was nearly 1.29-fold and 1.53-fold higher than that on corncob and poplar wood, respectively. Laccase activity was detected in almost all tested strains on cottonseed hull on the first day, while only a few strains on poplar wood and corncob were detected on the first day. These findings will be helpful for selecting the appropriate strain in industrial applications and for optimization of integrated industrial laccase production.


2007 ◽  
Vol 53 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Debing Jing ◽  
Peijun Li ◽  
Frank Stagnitti ◽  
Xianzhe Xiong

The regulation of culture conditions, especially the optimization of substrate constituents, is crucial for laccase production by solid fermentation. To develop an inexpensive optimized substrate formulation to produce high-activity laccase, a uniform design formulation experiment was devised. The solid fermentation of Trametes versicolor was performed with natural aeration, natural substrate pH (about 6.5), environmental humidity of 60% and two different temperature stages (at 37 °C for 3 days, and then at 30 °C for the next 17 days). From the experiment, a regression equation for laccase activity, in the form of a second-degree polynomial model, was constructed using multivariate regression analysis and solved with unconstrained optimization programming. The optimized substrate formulation for laccase production was then calculated. Tween 80 was found to have a negative effect on laccase production in solid fermentation; the optimized solid substrate formulation was 10.8% glucose, 27.7% wheat bran, 9.0% (NH4)2SO4, and 52.5% water. In a scaled-up verification of solid fermentation at a 10 kg scale, laccase activity from T. versicolor in the optimized substrate formulation reached 110.9 IU/g of dry mass.


Author(s):  
Siddharth Deshmukh ◽  
Pradnya Kanekar ◽  
Rama Bhadekar

Objective: To study 1) Optimization of nutritional and environmental parameters to enhance the yield of EPS by Halomonas smyrnensis SVD III isolated from seawater, West Coast of Maharashtra, India and 2) Purification and characterization of the EPS produced.Methods: The isolate was grown in Sehgal and Gibbons (SG) medium broth supplemented with 3% glucose, at 37 °C, 120 rpm for 7 d. Optimization of different parameters was carried out with one factor at a time approach. EPS was isolated from cell-free supernatant of the culture broth by centrifugation and precipitation using chilled ethanol, after removal of proteins by trichloroacetic acid (TCA) treatment. Characterization of the purified EPS was carried out with respect to fourier-transform infrared (FTIR) spectrum, 1H nuclear magnetic resonance (NMR) spectrum and mass spectrometry (MS) analysis.Results: Two-fold increase in the yield of EPS (23 g/l) by the selected isolate was obtained by using culture conditions as 10% inoculum size having cell density of 107 cells/ml, pH 6, incubation temperature 45 °C, 3% carbohydrate, 0.5% yeast extract as nitrogen source, 20% salt concentration and 7 d of incubation period. Characterization of the purified EPS suggested the presence of dominated glycosidic linkages and heptasaccharide nature of the molecule. As the present strain is halophilic, 20% NaCl was found to be optimum.Conclusion: Optimization studies resulted in two-fold increase in the yield of EPS which is of heptasaccharide nature.


2021 ◽  
Vol 22 (3) ◽  
pp. 1157
Author(s):  
Pablo Aza ◽  
Felipe de Salas ◽  
Gonzalo Molpeceres ◽  
David Rodríguez-Escribano ◽  
Iñigo de la Fuente ◽  
...  

Laccases secreted by saprotrophic basidiomycete fungi are versatile biocatalysts able to oxidize a wide range of aromatic compounds using oxygen as the sole requirement. Saccharomyces cerevisiae is a preferred host for engineering fungal laccases. To assist the difficult secretion of active enzymes by yeast, the native signal peptide is usually replaced by the preproleader of S. cerevisiae alfa mating factor (MFα1). However, in most cases, only basal enzyme levels are obtained. During directed evolution in S. cerevisiae of laccases fused to the α-factor preproleader, we demonstrated that mutations accumulated in the signal peptide notably raised enzyme secretion. Here we describe different protein engineering approaches carried out to enhance the laccase activity detected in the liquid extracts of S. cerevisiae cultures. We demonstrate the improved secretion of native and engineered laccases by using the fittest mutated α-factor preproleader obtained through successive laccase evolution campaigns in our lab. Special attention is also paid to the role of protein N-glycosylation in laccase production and properties, and to the introduction of conserved amino acids through consensus design enabling the expression of certain laccases otherwise not produced by the yeast. Finally, we revise the contribution of mutations accumulated in laccase coding sequence (CDS) during previous directed evolution campaigns that facilitate enzyme production.


2021 ◽  
Vol 6 (1) ◽  
pp. 91-98
Author(s):  
A. Bello ◽  
◽  
J. B. Ameh ◽  
D. A. Machido ◽  
A. I. Mohammed-Dabo

Laccases are oxidases with broad substrate specificity and ability to oxidize various phenolic and non-phenolic compounds. This study was carried out to isolate and characterizes laccase producing fungi from environment samples. Soil and decaying wood samples were collected from different locations within Ahmadu Bello University, Zaria Main campus. Suspensions of the samples (1 g in 10 mL sterile distilled water) were serially diluted, inoculated onto Potato Dextrose Agar (PDA) containing 0.01% Chloramphenicol and incubated for 7 days at 30oC.The fungal isolates were characterized macroscopically and microscopically with the aid of an atlas. The identified fungal isolates were screened for laccase production by inoculating onto PDA containing 0.02% Guaiacol, 1mM ABTS (2 2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) and 0.5% Tannic acid as indicator compounds and incubated at 250C for 7 days. The laccase producing isolates were confirmed molecularly by ITS rDNA sequence analysis using the FASTA algorithm with the Fungus database from the European Bioinformatics Institute (EBI).A total of 25 fungal species (11 from soil and 14 from decaying wood samples) were isolated. Two isolates from the soil origin identified as Curvularia lunata SSI7 (Accession No. QIE06317.1) and Fusarium clade VII SSI3 (Accession No. GQ505677) were found to produce laccase where Curvularia lunata SSI7 was able to oxidize all the indicator compounds used for the screening. Fusarium clade VII SSI3 was able to oxidize only 0.5% Tannic acid. Laccase producing Curvularia lunata and Fusarium clade VII were isolated from soil samples collected from ABU Zaria Main Campus. Keywords: laccase, fungi, soil, decaying wood


2013 ◽  
Vol 48 (1) ◽  
pp. 25-32 ◽  
Author(s):  
S Islam ◽  
B Feroza ◽  
AKMR Alam ◽  
S Begum

Pectinase activity among twelve different fungal strains, Aspergillus niger IM09 was identified as a potential one to produce maximal level 831 U/g at pH 4.0. Media composition, incubation temperature, incubation time, substrate concentration, aeration, inoculum size, assay temperature and nitrogen sources were found to effect pectinase activity. Moisture content did not affect the activity significantly. Media composition was varied to optimize the enzyme production in solid state fermentation. It was observed that the highest pectinase activity of 831.0 U/g was found to produce in presence of yeast extract as a nitrogen source in combination with ammonium sulfate in assay media. Aeration showed positive significant effects on pectinase production 755 U/g at 1000 ml flasks. The highest pectinase production was found at 2 g pectin (521 U/g) used as a substrate. Pectinolytic activity was found to have undergone catabolite repression with higher pectin concentration (205 U/g at 5 g pectin). The incubation period to achieve maximum pectinase activity by the isolated strain Aspergillus niger IM09 was 3 days, which is suitable from the commercial point of view. DOI: http://dx.doi.org/10.3329/bjsir.v48i1.15410 Bangladesh J. Sci. Ind. Res. 48(1), 25-32, 2013


2021 ◽  
Vol 25 (1) ◽  
pp. 574-586
Author(s):  
Marta Bertolini ◽  
Fosca Conti

Abstract Carbon dioxide emissions are strongly related to climate change and increase of global temperature. Whilst a complete change in producing materials and energy and in traffic and transportation systems is already in progress and circular economy concepts are on working, Carbon Capture and Storage (CCS) and Carbon Capture and Utilisation (CCU) represent technically practicable operative strategies. Both technologies have main challenges related to high costs, so that further advanced research is required to obtain feasible options. In this article, the focus is mainly on CCU using microalgae that are able to use CO2 as building block for value-added products such as biofuels, EPS (Extracellular Polymeric Substances), biomaterials and electricity. The results of three strains (UTEX 90, CC 2656, and CC 1010) of the microalgal organism Chlamydomonas reinhardtii are discussed. The results about ideal culture conditions suggest incubation temperature of 30 °C, pH between 6.5 and 7.0, concentrations of acetate between 1.6 and 2.3 g L–1 and of ammonium chloride between 0.1 and 0.5 g L–1, the addition of glucose This green microalga is a valid model system to optimize the production of biomass, carbohydrates and lipids.


2017 ◽  
Vol 11 (1) ◽  
pp. 13-18
Author(s):  
Ali J. R. AL-Sa'ady ◽  
Lamees M.R. Abbas ◽  
Hutaf A.A. ALsalim

Phenol oxidases (laccase), copper-containing oxidase enzymes, are found in many plants, fungi and microorganisms. Many factors that influence laccase production from Azotobacter chroococcum are determined in this study, these factors are: carbon source, nitrogen source, pH, incubation temperature and incubation period. The results showed that the best carbon and nitrogen sources for laccase production are sucrose and yeast extract respectively, and the best factors for laccase production conditions are pH 7.0 with an incubation period of 6 days at temperature 30 Cᵒ.


Marine Drugs ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. 537
Author(s):  
Valentina González ◽  
María José Vargas-Straube ◽  
Walter O. Beys-da-Silva ◽  
Lucélia Santi ◽  
Pedro Valencia ◽  
...  

Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes.


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