getpdf  NLM-PubMed-Logo  https://doi.org/10.17113/ftb.56.03.18.5348 

Lignin-Degrading Abilities of Novel Autochthonous Fungal Isolates Trametes hirsuta F13 and Stereum gausapatum F28

 

Jelena Jović*orcid tiny, Aneta Buntićorcid tiny, Neda Radovanovićorcid tiny, Bojan Petrovićorcid tiny and Ljiljana Mojovićorcid tiny

 

 


University of Belgrade, Faculty of Technology and Metallurgy, Department for Biochemical Engineering and Biotechnology, Karnegijeva 4, RS-11120 Belgrade, Serbia

 

 


Article histoy:
Received: 18 May 2017
Accepted: 26 March 2018
cc

 


Key words:
Trametes hirsuta, laccase, manganese peroxidase, Stereum gausapatum, lignin removal, white-rot fungi

 

 


Summary:
The aim of this research is to isolate and identify fungi with high lignin-degrading abilities that are autochthonous to southern Serbian region. Two novel fungal isolates identified as Trametes hirsuta F13 and Stereum gausapatum F28 were selected to assess their ligninolytic enzyme activities and the efficiency of lignin removal from beech wood sawdust. Obtained results show that both isolates are good sources of industrially valuable enzymes with a potential for application in various biotechnological and industrial processes. Both isolates showed laccase, manganese-dependent peroxidase, and versatile peroxidase activities, while only S. gausapatum F28 had lignin peroxidase activity. This is the first record of the ability of S. gausapatum species to produce lignin peroxidase. T. hirsuta F13 showed higher laccase activity than S. gausapatum F28, while S. gausapatum F28 had higher manganese peroxidase activity. Also, T. hirsuta F13 exhibited much higher laccase activity under submerged cultivation conditions than solid-state cultivation conditions, which is rare for fungi. This is important for industrial processes since the submerged fermentation is a dominant technique in industry. The test of the efficiency of lignin removal showed that both isolates are efficient lignin decomposers. After five weeks of incubation on beech wood sawdust, the total lignin losses were 33.84 % with T. hirsuta F13 and 28.8 % with S. gausapatum F28.

 

 


*Corresponding author: tel3 +381628766059
                                          email3  yowitch@gmx.com

getpdf  NLM-PubMed-Logo  https://doi.org/10.17113/ftb.56.03.18.5495 

Inhibition of Enzymatic and Oxidative Processes by Phenolic Extracts from Spirulina sp. and Nannochloropsis sp.

 

Priscila Tessmer Scaglioni1orcid tiny, Larissa Quadros1orcid tiny, Mariane de Paula1orcid tiny, Vitor Badiale Furlong2orcid tiny, Paulo César Abreu3orcid tiny and Eliana Badiale-Furlong1orcid tiny

 

 


1Laboratory of Food Science and Mycotoxins, School of Chemistry and Food, Federal University of Rio Grande (FURG), Itália Avenue, km 8, Bairro Carreiros, Rio Grande, RS, Brazil
2Chemical Engineering Department, Federal University of São Carlos (UFSCAR), Rod. Washington Luiz, km 235, SP 310, São Carlos, SP, Brazil
3Laboratory of Ecology of Phytoplankton and Marine Microorganisms, Aquaculture and Marine Biotechnology Center, Federal University of Rio Grande, Street of Hotel 2, Querência, Rio Grande, RS, Brazil

 

 


Article history:
Received: 31 August 2017
Accepted: 19 April 2018 
cc

 


Key words:
amylase, antioxidant activity, peroxidase, phenolic extracts, Nannochloropsis sp., Spirulina sp.

 

 


Summary:
This study investigates the capacity of phenolic extracts from microalgae Nannochloropsis sp. and Spirulina sp. to inhibit enzymes and free radical activities, intending to find an innovative way to slow down food damage. HPLC-UV and LC-MS/MS served to determine and confirm, respectively, the phenolic acid profiles in the soluble methanolic (free phenolic) and ethanolic (conjugated phenolic) fractions, and after hydrolysis (bound phenolic fractions). Different procedures measured the antioxidant activity of the extracts to estimate the minimal concentration for the protective effect, stability and versatility of activity. The ability to inhibit the oxidative process (ABTS and DPPH), α-amylase and peroxidase activities were estimated as specific inhibition (%/(min·μg)) for better comparison between the phenolic sources. The phenolic acid mass fractions in the free phenolic extracts from Spirulina sp. and Nannochloropsis sp. were 628 and 641 μg/g, respectively. Phenolic extract from Nannochloropsis sp. showed the highest value of ABTS inhibition (1.3 %/(min·μg)) and highest inhibition of peroxidase activity (0.4 %/(min·μg)). The extract from Spirulina sp. was a better inhibitor of α-amylase activity (0.07 %/(min·μg)). Therefore, the phenolic extracts from the edible microalgae may be applied in food industry as natural protector against endogenous and exogenous hydrolytic and oxidative processes.

 

 


*Corresponding author: tel3 +555332757387
                                          email3  priscilascaglioni@gmail.com

getpdf  NLM-PubMed-Logo  https://doi.org/10.17113/ftb.56.03.18.5618 

Electrochemical Study and Determination of All-trans-Retinol at Carbon Paste Electrode Modified by a Surfactant

 

Simona Žabčíkováorcid tiny, Tomáš Mikysekorcid tiny, Libor Červenkaorcid tiny and Milan Sýs*orcid tiny

 

 


Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ-53210 Pardubice, Czech Republic

 

 


Article history:
Received: 22 November 2017
Accepted: 9 May 2018 
cc

 


Key words:
modified carbon paste electrode, differential pulse voltammetry, glassy carbon electrode, all-trans-retinol, surfactant

 

 


Summary:
The oxidation mechanism of all-trans-retinol (vitamin A1) and its several esters in non-aqueous, aqueous organic mixture, and pure aqueous media was investigated by cyclic voltammetry. The oxidation occurred in several irreversible steps. The calculated highest density of electrons in retinoid molecules which are delocalized over carbon atoms of the five conjugated double bonds (C5-C14) was found in the part of the molecule involved in oxidation processes. The most sensitive oxidation peak (at +0.8 V vs Ag/AgCl) was used for development of new direct voltammetric method based on differential pulse voltammetry for the determination of retinol at carbon paste electrode modified with surfactant sodium dodecyl sulfate (CPE/SDS). The results show that 30 % (by mass) of modifier SDS exhibited optimal sensitivity and shape of voltammograms. Compared to commonly used glassy carbon electrode (GCE), the CPE/SDS showed significant progress in the retinol electroanalysis. The linear ranges for retinol determination were 1.5·10−6–1.8·10−4 M for CPE/SDS and 4.4·10−6–7.0·10−4 M for GCE with the detection limits of 1.3·10−6 and 4.6·10−7 M, respectively.

 

 


*Corresponding author: tel2 +420466037068
                                           fax2 +420466037279
                                           email3  milan.sys@upce.cz

getpdf  NLM-PubMed-Logo  https://doi.org/10.17113/ftb.56.03.18.5726 

Development of a New Colorimetric Chemosensor for Selective Determination of Urinary and Vegetable Oxalate Concentration Through an Indicator Displacement Assay (IDA) in Aqueous Media

 


Hossein Tavallali*orcid tiny, Gohar Deilamy-Radorcid tiny and Narges Mosallanejadorcid tiny

 

 

 

Department of Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran

 

 


Article history:
Received: 14 February 2018
Accepted: 8 May 2018 
cc 

 


Key words:
colorimetric chemosensor, indicator displacement assay, copper complex, oxalate, urine

 

 


Summary:
The paper proposes a method that exhibits operational simplicity for the indirect spectrophotometric determination of oxalate ion. We developed Reactive Blue 4 (RB4) as a sensor by complexation with copper ion as a simple, inexpensive yet selective colorimetric chemosensing ensemble for the recognition of oxalate over other available competitive analytes via indicator displacement assay (IDA) in both solution (aqueous medium) and solid state (paper-based experiment). The addition of oxalate to RB4-Cu2+ complex changed the colour from sky blue to dark blue due to the regeneration of RB4 by the chelation of oxalate as the competitive analyte with Cu2+. The absorbance band increase is linear with oxalate concentration from 1.76 to 49.4 µmol/L with a detection limit of 0.62 µmol/L. This measurement mode did not show any influence of interferences (available anions and ascorbic acid). This approach eliminated the need for the separation stages, enzymatic multiple-step reactions, sample preparation, organic solvent mixture, chemical modifications and equipment developed to a high degree of complexity. The oxalate determination gave results in different real samples such as urine, mushroom and spinach, which demonstrated the applicability of the existing method. Furthermore, this colorimetric system can serve as IMPLICATION molecular logic gate using Cu2+ and oxalate (C2O2–) as inputs and UV-Vis absorbance signal as the output with potential monitoring applications.

 

 


*Corresponding author: tel3 +989173153520
                                          fax2 +987136222249
                                          email3  Tavallali@pnu.ac.ir

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