Robert F H Dekker - Academia.edu (original) (raw)
Papers by Robert F H Dekker
Letters in Applied Microbiology, Aug 1, 1996
ABSTRACT A.M. BARBOSA, R.F.H. DEKKER AND G.E. ST HARDY. 1996. Forty fungi isolated from diverse e... more ABSTRACT A.M. BARBOSA, R.F.H. DEKKER AND G.E. ST HARDY. 1996. Forty fungi isolated from diverse environments in Western Australia were screened for ligninolytic activity based on in-vivo decolorization of the polymeric dye Poly R-478. Three isolates identified as Aspergillus, Botryosphaeria and Coniochaeta species were selected for further studies. The Botryosphaeria and Coniochaeta isolates were found to produce laccase constitutively in submerged culture when grown on glucose, or on ryegrass seed by solid state fermentation. A comparison of the three isolates grown on glucose in the presence of 3,4-dimethoxybenzyl (veratryl) alcohol (40 mmol 1−1) showed that only the Botryosphaeria isolate produced laccase, with laccase activities 115-fold higher than when grown on glucose alone.
Fuel, Feb 1, 2019
Tetramethoxybiphenyl-4,4′-diol (TMBP) is described in the literature as having antioxidant activi... more Tetramethoxybiphenyl-4,4′-diol (TMBP) is described in the literature as having antioxidant activity, and can be obtained through enzyme-catalyzed processes. Its use as an additive to biodiesel offers a more sustainable substitute for the antioxidants commonly used for the conservation of this type of biofuel. In this work, TMBP was synthesized from 2,6-dimethoxyphenol catalyzed by the laccase from Botryosphaeria rhodina MAMB-05, and applied to soybean biodiesel to evaluate its antioxidant action by the determination of the induction period, and kinetic and thermodynamic oxidation parameters. Biodiesel samples containing TMBP presented induction periods higher than the 6 h in the Rancimat test conducted at 110°C. The reaction rate constants at all temperatures examined were lower than those obtained for samples containing tert-butylhydroxytoluene (BHT), a common synthetic antioxidant added to biodiesel. The kinetic and thermodynamic parameters of oxidation indicated the effectiveness of TMBP in the inhibition of oxidative processes in soybean biodiesel compared to BHT. The antioxidant action of TMBP was not impaired as a function of thermal degradation, as thermogravimetry analyzes indicated degradation events occurring only above 270°C.
Bioenergy Research, Sep 14, 2015
In this study on the valorization of hemicelluloses (a co-product generated during cellulosic bio... more In this study on the valorization of hemicelluloses (a co-product generated during cellulosic bioethanol production), prehydrolyzates obtained from poplar woodchips pretreated in an industrial experimental steam-explosion pilot-plant facility were evaluated for the production of bioxylitol using the yeast, Candida guilliermondii FTI 20037, employing both batch and fed-batch fermentation modes in shake flasks on defined nutrient medium. The prehydrolyzates consisted of monosaccharides (pentose and hexose sugars) as well as xylo-oligosaccharides and undegraded hemicellulose. Xylose (31.6 ± 0.57 g/L) was the major sugar in the prehydrolyzates that also contained acetic acid and degradation products of lignin and sugars (phenolic and furanic compounds). Xylose in the prehydrolyzates could be further increased (106.4 ± 0.02 g/L) through an acid hydrolysis step (0.6 % (w/v) H2SO4). Compounds of a toxic nature in both the acid hydrolyzates and prehydrolyzates were removed by treatment with Amberlite IRA-400 resin (chloride form). Batch fermentation of pure xylose and poplar prehydrolyzate resulted in bioxylitol production of 9.9 ± 0.01 and 4.9 ± 0.17 g/L, respectively, indicating that the poplar prehydrolyzates exhibited an inhibitory effect on fermentation. After detoxification of the poplar prehydrolyzates, bioxylitol production increased to 8.9 ± 0.01 g/L. Fed-batch fermentation of the prehydrolyzate increased the bioxylitol production to 12.39 ± 0.33 g/L, while acid hydrolysis followed by detoxification resulted in a maximum bioxylitol production of 22.0 ± 0.01 g/L, a 348 % increase. The results demonstrated that acid hydrolysis and detoxification followed by fed-batch fermentation was an efficient way to produce bioxylitol from poplar prehydrolyzates.
RESUMO: As glucanas sao polimeros de acucar que podem ter centenas ou milhares de monossacarideos... more RESUMO: As glucanas sao polimeros de acucar que podem ter centenas ou milhares de monossacarideos como unidades monomericas, tendo origem animal ou vegetal. Estas macromoleculas apresentam funcionalidades como potencial antioxidante, habilidade hipocolesterolemica, modulacao da resposta biologica, entre outras. A derivatizacao quimica da estrutura primaria das glucanas tem se mostrado uma importante ferramenta para potencializar estas funcionalidades biologicas. Dentre as modificacoes quimicas existentes ha a sulfonacao, onde grupos sulfonicos (S + O 2 OH) sao inseridos na estrutura. O presente estudo teve como objetivo a derivatizacao quimica por sulfonacao da lasiodiplodana produzida pelo fungo L. theobromae MMPI, bem como a avaliacao do grau de sulfonacao e caracterizacao parcial do derivado. O metodo acido clorosulfonico – piridina foi empregado na sulfonacao da lasiodiplodana nativa e promoveu a obtencao de um derivado com baixo grau de substituicao (DS: 0,15). A sulfonacao foi confirmada por espectroscopia no infravermelho com transformada de Fourier. Bandas nas regioes de 1227 cm -1 e 803 cm -1 , correspondentes a vibracoes especificas do grupo S=O (alongamento simetrico) e do grupo C-O-S (vibracao simetrica) associado ao grupo C-O-SO 3 foram verificadas na amostra derivatizada. Analise por microscopia eletronica de varredura indicou que a derivatizacao promoveu mudancas na estrutura morfologica do biopolimero lasiodiplodana.
Este resumo expandido está licenciado sob os termos da Licença Creative Commons-Atribuição-Não Co... more Este resumo expandido está licenciado sob os termos da Licença Creative Commons-Atribuição-Não Comercial 4.0 Internacional.
As β-glucanas sao polissacarideos encontrados na parede celular de alguns microrganismos e cereai... more As β-glucanas sao polissacarideos encontrados na parede celular de alguns microrganismos e cereais e tambem podem ser produzidas extracelularmente por determinados fungos filamentosos. Estas macromoleculas podem apresentar propriedades biologicas, como atividade anticoagulante, antioxidante, anticarcinogenica, hipocolesterolemica, alem de auxiliarem na reducao de riscos cardiovasculares e diabetes. Tais propriedades podem ser potencializadas a partir de modificacoes quimicas na molecula, incluindo a derivatizacao por sulfonacao, onde grupos sulfonatos sao inseridos na estrutura. No presente trabalho a (1→6)-β-D-glucana (lasiodiplodana) produzida pelo fungo L. theobromae MMPI foi derivatizada por sulfonacao e o derivado obtido foi caracterizado quanto ao potencial antioxidante e antimicrobiano. O protocolo de sulfonacao empregado levou a obtencao de um derivado sulfonado com baixo grau de substituicao (DS: 0,24). A sulfonacao contribuiu para a potencializacao da atividade antioxidante, sendo verificada aumento da capacidade de remocao de peroxido de hidrogenio do meio e do potencial redutor. Lasiodiplodana sulfonada apresentou atividade bacteriostatica em concentracoes acima de 325 µg.mL -1 frente a S. aureus . Estudos posteriores sao importantes para obtencao de derivados com maior grau de sulfonacao, os quais possivelmente apresentarao maior atividade antioxidante, habilidade antimicrobiana, alem de outras funcionalidades biologicas.
DOAJ (DOAJ: Directory of Open Access Journals), Oct 1, 2014
The effects of soybean and castorbean meals were evaluated separately, and in combinations at dif... more The effects of soybean and castorbean meals were evaluated separately, and in combinations at different ratios, as substrates for lipase production by Botryosphaeria ribis EC-01 in submerged fermentation using only distilled water. The addition of glycerol analytical grade (AG) and glycerol crude (CG) to soybean and castorbean meals separately and in combination, were also examined for lipase production. Glycerol-AG increased enzyme production, whereas glycerol-CG decreased it. A 2(4) factorial design was developed to determine the best concentrations of soybean meal, castorbean meal, glycerol-AG, and KH2PO4 to optimize lipase production by B. ribis EC-01. Soybean meal and glycerol-AG had a significant effect on lipase production, whereas castorbean meal did not. A second treatment (2(2) factorial design central composite) was developed, and optimal lipase production (4,820 U/g of dry solids content (ds)) was obtained when B. ribis EC-01 was grown on 0.5 % (w/v) soybean meal and 5.2 % (v/v) glycerol in distilled water, which was in agreement with the predicted value (4,892 U/g ds) calculated by the model. The unitary cost of lipase production determined under the optimized conditions developed ranged from US$0.42 to 0.44 based on nutrient costs. The fungal lipase was immobilized onto Celite and showed high thermal stability and was used for transesterification of soybean oil in methanol (1:3) resulting in 36 % of fatty acyl alkyl ester content. The apparent K m and V max were determined and were 1.86 mM and 14.29 μmol min(-1) mg(-1), respectively.
Biomacromolecules, Sep 29, 2022
Proceedings of the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007), 2009
This book contains a compilation of papers presented at the II International Conference on Enviro... more This book contains a compilation of papers presented at the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007) held in Seville, Spain on 28 November - 1 December 2007, where over 550 researchers from about 60 ...
Fermentation Technology, 2012
β-(1→3)-Glucanases were produced by Trichoderma harzianum Rifai PAMB-86 cultivated on botryosphae... more β-(1→3)-Glucanases were produced by Trichoderma harzianum Rifai PAMB-86 cultivated on botryosphaeran in a bench-fermenter and optimised by the response surface method. Maximal enzyme titres occurred at 5 days, initial pH 5.5 and aeration of 1.5vvm. β-(1→3)-The β-glucanolytic enzyme complex produced by T. harzianum Rifai PAMB-86 was fractionated by gel filtration into 2 fractions (F-I, F-II), and employed to produce gluco-oligosaccharides from algal paramylon ((1→3)-β-D-glucan) and lichen pustulan ((1→6)-β-D-glucan). Both enzymes attacked paramylon to the extent of ~15-20% in 30 min releasing glucose and laminaribiose as major end-products, and laminarioligosaccharides of degree of polymerization (DP) ≥3. Only F-I degraded pustulan resulting in ~2% degradation at 30 min, with glucose, gentiobiose and gentio-oligosaccharides of DP ≥4 as major products. The difference in the nature of the hydrolysis products can be explained by the substrate specificities of each enzyme fraction, and the structural differences of the β-D-glucans attacked.
Biologically-inspired systems, 2019
Glucans find a wide range of commercial applications in different industrial sectors, food, pharm... more Glucans find a wide range of commercial applications in different industrial sectors, food, pharmaceuticals, and fine chemicals. Commercially available β-glucans are obtained chiefly through complex extraction procedures of the cell walls of microorganisms and cereals that are time-consuming processes. Some microorganisms also produce β-glucans exocellularly, which have been exploited commercially for this purpose. In this context, exopolysaccharides such as lasiodiplodan (a linear (1 → 6) β-glucan) standout because of the greater ease of their production by submerged fermentation and recovery from the cell-free fermentation broth by precipitation methods. Lasiodiplodan from the fungus Lasiodiplodia theobromae MMPI was first described in 2008, and studies have since addressed its production, chemical derivatization, and chemical and biological characterization. Lasiodiplodan presents biological functions that include antioxidant, hypoglycemic, antiproliferative, and transaminase activities, as well as protective activity against doxorubicin-induced DNA damage. The different biological properties of lasiodiplodan make it a biomolecule attractive for commercial exploitation. Medicines for treatments of different conditions of human diseases, containing lasiodiplodan as one of the active or co-adjuvant principles, could be developed by the pharmaceutical industry. Antiaging creams and ointments, as well as self-healing hydrogels, are also good possibilities for commercial applications. Another attractive possibility of use is as a prebiotic agent in food products. Chemical modifications in the lasiodiplodan structure by O-acetylation, carboxymethylation, phosphorylation, or sulfonylation have been shown to be a potentiating mechanism of some of its properties. This chapter addresses the studies that have been carried out with lasiodiplodan and future production perspectives and applications.
International Journal of Biological Macromolecules, Jul 1, 2021
A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its w... more A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its wound healing potential was evaluated. β-Glucans have attracted much interest by the cosmetic industry sector because of their bioactive and functional properties and in promoting skin health. In the present study an β-glucan was studied as a healing biomaterial that has not hitherto been reported in the scientific literature. LAS produced by the ascomycete Lasiodiplodia theobromae MMPI was used in the formulation of a healing hydrogel. Physicochemical and microbiological quality parameters, antioxidant potential and stability of the formulation was evaluated. FTIR, thermal analysis and SEM techniques were also employed in the characterization. Wistar rats were used as a biological model to investigate the wound healing potential. Histological analyses of cutaneous tissue from the dorsal region were conducted after 4, 7, 10 and 14 days of treatment, and evaluated re-epithelialization, cell proliferation and collagen production. Physicochemical stability, microbiological quality and antioxidant potential, especially in relation to its ability to scavenge hydroxyl radicals were found. The hydrogel stimulated cell re-epithelialization and proliferation during all days of the treatment, and stimulated an increase of collagen fibers. Lasiodiplodan showed immunomodulatory activity in wound healing and this biomacromolecule could be an alternative compound in wound care.
Biotechnology Progress, Mar 6, 2019
The ascomycetous fungus, Botryosphaeria rhodina MAMB-05, secretes a (1→3)(1→6)-β-D-glucan, and th... more The ascomycetous fungus, Botryosphaeria rhodina MAMB-05, secretes a (1→3)(1→6)-β-D-glucan, and the scaled-up production of this β-glucan results in large amounts of mycelial biomass being produced that represent a potentially cost-effective biosorbent for rare-earth elements. High sorption capacities for both La(III) and Sm(III) were demonstrated for viable and autoclaved lyophilized fungal mycelium. FT-IR absorption spectra and the point of zero charge were similar for the viable and inactive fungal mycelia. The rare-earth lanthanide elements (La and Sm) binding increased at initial pH values greater than 5.0, which was also observed for the point of zero charge determination. The maximum La(III) uptake capacity was observed at lower amounts of La(III) ions in solution, decreasing Bioseparations and Downstream Processing
Applied Catalysis A-general, Apr 1, 2018
Highlights Botryosphaeria rhodina MAMB-05 laccase catalyzed synthesis of 3 dimers from 2,6-dime... more Highlights Botryosphaeria rhodina MAMB-05 laccase catalyzed synthesis of 3 dimers from 2,6-dimethoxyphenol at different pH and reaction times Dimers were formed by oxidative coupling via CC (I, II) and CO (III) bonds
Enzyme and microbial technology, 2001
The ascomycete, Botryosphaeria sp, produced two extracellular constitutive laccases (PPO-I and PP... more The ascomycete, Botryosphaeria sp, produced two extracellular constitutive laccases (PPO-I and PPO-II) active toward the substrates: 2, 2 1-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) [ABTS], and 2,6-dimethoxyphenol (DMP), respectively. The production of both laccases increased when the fungal isolate was grown in the presence of veratryl alcohol, and resulted in optimal laccase production (100and 25-fold, respectively) at 40 mM. The effect of aeration on growth and laccase production was studied in baffled flasks, and showed that aeration of the cultures increased the production of both enzymes 4-5 fold in the presence of veratryl alcohol. Both laccases were susceptible to inhibition by azide, acetate and chloride anions. Veratryl alcohol inhibited the laccase-catalyzed polymerization of DMP. Growing cultures of Botryosphaeria sp. produced an exopolysaccharide of the -glucan type whose synthesis was depressed when grown in the presence of veratryl alcohol.
Antonella Carvalho de Oliveira eBooks, Jan 16, 2019
(CIP) (eDOC BRASIL, Belo Horizonte/MG) I34 Impactos das tecnologias nas ciências biológicas e da ... more (CIP) (eDOC BRASIL, Belo Horizonte/MG) I34 Impactos das tecnologias nas ciências biológicas e da saúde 2 [recurso eletrônico] / Organizadora Christiane Trevisan Slivinski.-Ponta Grossa (PR): Atena Editora, 2019.-(Impactos das Tecnologias nas Ciências Biológicas e da Saúde; v. 2) Formato: PDF Requisitos de sistema: Adobe Acrobat Reader Modo de acesso: World Wide Web Inclui bibliografia
Cell Biochemistry and Function
Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)‐β‐d‐glucan (botryosp... more Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)‐β‐d‐glucan (botryosphaeran) have been described in the literature, but its effects on inflammation have not been evaluated. This study aimed to investigate the action of botryosphaeran on experimental mice models of carrageenan‐induced acute pleurisy and acute paw edema, and complete Freund's adjuvant‐induced persistent paw edema. All botryosphaeran doses tested (1.0, 2.5, 5.0, and 10.0 mg/kg birth weight [b.w.], orally administered) reduced leukocyte recruitment, nitric oxide (NO) levels, and protein extravasation in the pleural cavity. Botryosphaeran (5 mg/kg b.w.) did not diminish edema and mechanical hyperalgesia in the paw within 4 h; however, cold allodynia was alleviated within the first 2 h. In the persistent paw inflammation model, the effects of daily oral administration of botryosphaeran (5 mg/kg b.w.) were evaluated over 3 and 7 days. The fungal β‐glucan significantly reduced the levels of t...
Impactos das tecnologias nas ciências biológicas e da saúde 3, 2019
Impactos das Tecnologias nas Ciências Biológicas e da Saúde 3
Letters in Applied Microbiology, Aug 1, 1996
ABSTRACT A.M. BARBOSA, R.F.H. DEKKER AND G.E. ST HARDY. 1996. Forty fungi isolated from diverse e... more ABSTRACT A.M. BARBOSA, R.F.H. DEKKER AND G.E. ST HARDY. 1996. Forty fungi isolated from diverse environments in Western Australia were screened for ligninolytic activity based on in-vivo decolorization of the polymeric dye Poly R-478. Three isolates identified as Aspergillus, Botryosphaeria and Coniochaeta species were selected for further studies. The Botryosphaeria and Coniochaeta isolates were found to produce laccase constitutively in submerged culture when grown on glucose, or on ryegrass seed by solid state fermentation. A comparison of the three isolates grown on glucose in the presence of 3,4-dimethoxybenzyl (veratryl) alcohol (40 mmol 1−1) showed that only the Botryosphaeria isolate produced laccase, with laccase activities 115-fold higher than when grown on glucose alone.
Fuel, Feb 1, 2019
Tetramethoxybiphenyl-4,4′-diol (TMBP) is described in the literature as having antioxidant activi... more Tetramethoxybiphenyl-4,4′-diol (TMBP) is described in the literature as having antioxidant activity, and can be obtained through enzyme-catalyzed processes. Its use as an additive to biodiesel offers a more sustainable substitute for the antioxidants commonly used for the conservation of this type of biofuel. In this work, TMBP was synthesized from 2,6-dimethoxyphenol catalyzed by the laccase from Botryosphaeria rhodina MAMB-05, and applied to soybean biodiesel to evaluate its antioxidant action by the determination of the induction period, and kinetic and thermodynamic oxidation parameters. Biodiesel samples containing TMBP presented induction periods higher than the 6 h in the Rancimat test conducted at 110°C. The reaction rate constants at all temperatures examined were lower than those obtained for samples containing tert-butylhydroxytoluene (BHT), a common synthetic antioxidant added to biodiesel. The kinetic and thermodynamic parameters of oxidation indicated the effectiveness of TMBP in the inhibition of oxidative processes in soybean biodiesel compared to BHT. The antioxidant action of TMBP was not impaired as a function of thermal degradation, as thermogravimetry analyzes indicated degradation events occurring only above 270°C.
Bioenergy Research, Sep 14, 2015
In this study on the valorization of hemicelluloses (a co-product generated during cellulosic bio... more In this study on the valorization of hemicelluloses (a co-product generated during cellulosic bioethanol production), prehydrolyzates obtained from poplar woodchips pretreated in an industrial experimental steam-explosion pilot-plant facility were evaluated for the production of bioxylitol using the yeast, Candida guilliermondii FTI 20037, employing both batch and fed-batch fermentation modes in shake flasks on defined nutrient medium. The prehydrolyzates consisted of monosaccharides (pentose and hexose sugars) as well as xylo-oligosaccharides and undegraded hemicellulose. Xylose (31.6 ± 0.57 g/L) was the major sugar in the prehydrolyzates that also contained acetic acid and degradation products of lignin and sugars (phenolic and furanic compounds). Xylose in the prehydrolyzates could be further increased (106.4 ± 0.02 g/L) through an acid hydrolysis step (0.6 % (w/v) H2SO4). Compounds of a toxic nature in both the acid hydrolyzates and prehydrolyzates were removed by treatment with Amberlite IRA-400 resin (chloride form). Batch fermentation of pure xylose and poplar prehydrolyzate resulted in bioxylitol production of 9.9 ± 0.01 and 4.9 ± 0.17 g/L, respectively, indicating that the poplar prehydrolyzates exhibited an inhibitory effect on fermentation. After detoxification of the poplar prehydrolyzates, bioxylitol production increased to 8.9 ± 0.01 g/L. Fed-batch fermentation of the prehydrolyzate increased the bioxylitol production to 12.39 ± 0.33 g/L, while acid hydrolysis followed by detoxification resulted in a maximum bioxylitol production of 22.0 ± 0.01 g/L, a 348 % increase. The results demonstrated that acid hydrolysis and detoxification followed by fed-batch fermentation was an efficient way to produce bioxylitol from poplar prehydrolyzates.
RESUMO: As glucanas sao polimeros de acucar que podem ter centenas ou milhares de monossacarideos... more RESUMO: As glucanas sao polimeros de acucar que podem ter centenas ou milhares de monossacarideos como unidades monomericas, tendo origem animal ou vegetal. Estas macromoleculas apresentam funcionalidades como potencial antioxidante, habilidade hipocolesterolemica, modulacao da resposta biologica, entre outras. A derivatizacao quimica da estrutura primaria das glucanas tem se mostrado uma importante ferramenta para potencializar estas funcionalidades biologicas. Dentre as modificacoes quimicas existentes ha a sulfonacao, onde grupos sulfonicos (S + O 2 OH) sao inseridos na estrutura. O presente estudo teve como objetivo a derivatizacao quimica por sulfonacao da lasiodiplodana produzida pelo fungo L. theobromae MMPI, bem como a avaliacao do grau de sulfonacao e caracterizacao parcial do derivado. O metodo acido clorosulfonico – piridina foi empregado na sulfonacao da lasiodiplodana nativa e promoveu a obtencao de um derivado com baixo grau de substituicao (DS: 0,15). A sulfonacao foi confirmada por espectroscopia no infravermelho com transformada de Fourier. Bandas nas regioes de 1227 cm -1 e 803 cm -1 , correspondentes a vibracoes especificas do grupo S=O (alongamento simetrico) e do grupo C-O-S (vibracao simetrica) associado ao grupo C-O-SO 3 foram verificadas na amostra derivatizada. Analise por microscopia eletronica de varredura indicou que a derivatizacao promoveu mudancas na estrutura morfologica do biopolimero lasiodiplodana.
Este resumo expandido está licenciado sob os termos da Licença Creative Commons-Atribuição-Não Co... more Este resumo expandido está licenciado sob os termos da Licença Creative Commons-Atribuição-Não Comercial 4.0 Internacional.
As β-glucanas sao polissacarideos encontrados na parede celular de alguns microrganismos e cereai... more As β-glucanas sao polissacarideos encontrados na parede celular de alguns microrganismos e cereais e tambem podem ser produzidas extracelularmente por determinados fungos filamentosos. Estas macromoleculas podem apresentar propriedades biologicas, como atividade anticoagulante, antioxidante, anticarcinogenica, hipocolesterolemica, alem de auxiliarem na reducao de riscos cardiovasculares e diabetes. Tais propriedades podem ser potencializadas a partir de modificacoes quimicas na molecula, incluindo a derivatizacao por sulfonacao, onde grupos sulfonatos sao inseridos na estrutura. No presente trabalho a (1→6)-β-D-glucana (lasiodiplodana) produzida pelo fungo L. theobromae MMPI foi derivatizada por sulfonacao e o derivado obtido foi caracterizado quanto ao potencial antioxidante e antimicrobiano. O protocolo de sulfonacao empregado levou a obtencao de um derivado sulfonado com baixo grau de substituicao (DS: 0,24). A sulfonacao contribuiu para a potencializacao da atividade antioxidante, sendo verificada aumento da capacidade de remocao de peroxido de hidrogenio do meio e do potencial redutor. Lasiodiplodana sulfonada apresentou atividade bacteriostatica em concentracoes acima de 325 µg.mL -1 frente a S. aureus . Estudos posteriores sao importantes para obtencao de derivados com maior grau de sulfonacao, os quais possivelmente apresentarao maior atividade antioxidante, habilidade antimicrobiana, alem de outras funcionalidades biologicas.
DOAJ (DOAJ: Directory of Open Access Journals), Oct 1, 2014
The effects of soybean and castorbean meals were evaluated separately, and in combinations at dif... more The effects of soybean and castorbean meals were evaluated separately, and in combinations at different ratios, as substrates for lipase production by Botryosphaeria ribis EC-01 in submerged fermentation using only distilled water. The addition of glycerol analytical grade (AG) and glycerol crude (CG) to soybean and castorbean meals separately and in combination, were also examined for lipase production. Glycerol-AG increased enzyme production, whereas glycerol-CG decreased it. A 2(4) factorial design was developed to determine the best concentrations of soybean meal, castorbean meal, glycerol-AG, and KH2PO4 to optimize lipase production by B. ribis EC-01. Soybean meal and glycerol-AG had a significant effect on lipase production, whereas castorbean meal did not. A second treatment (2(2) factorial design central composite) was developed, and optimal lipase production (4,820 U/g of dry solids content (ds)) was obtained when B. ribis EC-01 was grown on 0.5 % (w/v) soybean meal and 5.2 % (v/v) glycerol in distilled water, which was in agreement with the predicted value (4,892 U/g ds) calculated by the model. The unitary cost of lipase production determined under the optimized conditions developed ranged from US$0.42 to 0.44 based on nutrient costs. The fungal lipase was immobilized onto Celite and showed high thermal stability and was used for transesterification of soybean oil in methanol (1:3) resulting in 36 % of fatty acyl alkyl ester content. The apparent K m and V max were determined and were 1.86 mM and 14.29 μmol min(-1) mg(-1), respectively.
Biomacromolecules, Sep 29, 2022
Proceedings of the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007), 2009
This book contains a compilation of papers presented at the II International Conference on Enviro... more This book contains a compilation of papers presented at the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007) held in Seville, Spain on 28 November - 1 December 2007, where over 550 researchers from about 60 ...
Fermentation Technology, 2012
β-(1→3)-Glucanases were produced by Trichoderma harzianum Rifai PAMB-86 cultivated on botryosphae... more β-(1→3)-Glucanases were produced by Trichoderma harzianum Rifai PAMB-86 cultivated on botryosphaeran in a bench-fermenter and optimised by the response surface method. Maximal enzyme titres occurred at 5 days, initial pH 5.5 and aeration of 1.5vvm. β-(1→3)-The β-glucanolytic enzyme complex produced by T. harzianum Rifai PAMB-86 was fractionated by gel filtration into 2 fractions (F-I, F-II), and employed to produce gluco-oligosaccharides from algal paramylon ((1→3)-β-D-glucan) and lichen pustulan ((1→6)-β-D-glucan). Both enzymes attacked paramylon to the extent of ~15-20% in 30 min releasing glucose and laminaribiose as major end-products, and laminarioligosaccharides of degree of polymerization (DP) ≥3. Only F-I degraded pustulan resulting in ~2% degradation at 30 min, with glucose, gentiobiose and gentio-oligosaccharides of DP ≥4 as major products. The difference in the nature of the hydrolysis products can be explained by the substrate specificities of each enzyme fraction, and the structural differences of the β-D-glucans attacked.
Biologically-inspired systems, 2019
Glucans find a wide range of commercial applications in different industrial sectors, food, pharm... more Glucans find a wide range of commercial applications in different industrial sectors, food, pharmaceuticals, and fine chemicals. Commercially available β-glucans are obtained chiefly through complex extraction procedures of the cell walls of microorganisms and cereals that are time-consuming processes. Some microorganisms also produce β-glucans exocellularly, which have been exploited commercially for this purpose. In this context, exopolysaccharides such as lasiodiplodan (a linear (1 → 6) β-glucan) standout because of the greater ease of their production by submerged fermentation and recovery from the cell-free fermentation broth by precipitation methods. Lasiodiplodan from the fungus Lasiodiplodia theobromae MMPI was first described in 2008, and studies have since addressed its production, chemical derivatization, and chemical and biological characterization. Lasiodiplodan presents biological functions that include antioxidant, hypoglycemic, antiproliferative, and transaminase activities, as well as protective activity against doxorubicin-induced DNA damage. The different biological properties of lasiodiplodan make it a biomolecule attractive for commercial exploitation. Medicines for treatments of different conditions of human diseases, containing lasiodiplodan as one of the active or co-adjuvant principles, could be developed by the pharmaceutical industry. Antiaging creams and ointments, as well as self-healing hydrogels, are also good possibilities for commercial applications. Another attractive possibility of use is as a prebiotic agent in food products. Chemical modifications in the lasiodiplodan structure by O-acetylation, carboxymethylation, phosphorylation, or sulfonylation have been shown to be a potentiating mechanism of some of its properties. This chapter addresses the studies that have been carried out with lasiodiplodan and future production perspectives and applications.
International Journal of Biological Macromolecules, Jul 1, 2021
A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its w... more A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its wound healing potential was evaluated. β-Glucans have attracted much interest by the cosmetic industry sector because of their bioactive and functional properties and in promoting skin health. In the present study an β-glucan was studied as a healing biomaterial that has not hitherto been reported in the scientific literature. LAS produced by the ascomycete Lasiodiplodia theobromae MMPI was used in the formulation of a healing hydrogel. Physicochemical and microbiological quality parameters, antioxidant potential and stability of the formulation was evaluated. FTIR, thermal analysis and SEM techniques were also employed in the characterization. Wistar rats were used as a biological model to investigate the wound healing potential. Histological analyses of cutaneous tissue from the dorsal region were conducted after 4, 7, 10 and 14 days of treatment, and evaluated re-epithelialization, cell proliferation and collagen production. Physicochemical stability, microbiological quality and antioxidant potential, especially in relation to its ability to scavenge hydroxyl radicals were found. The hydrogel stimulated cell re-epithelialization and proliferation during all days of the treatment, and stimulated an increase of collagen fibers. Lasiodiplodan showed immunomodulatory activity in wound healing and this biomacromolecule could be an alternative compound in wound care.
Biotechnology Progress, Mar 6, 2019
The ascomycetous fungus, Botryosphaeria rhodina MAMB-05, secretes a (1→3)(1→6)-β-D-glucan, and th... more The ascomycetous fungus, Botryosphaeria rhodina MAMB-05, secretes a (1→3)(1→6)-β-D-glucan, and the scaled-up production of this β-glucan results in large amounts of mycelial biomass being produced that represent a potentially cost-effective biosorbent for rare-earth elements. High sorption capacities for both La(III) and Sm(III) were demonstrated for viable and autoclaved lyophilized fungal mycelium. FT-IR absorption spectra and the point of zero charge were similar for the viable and inactive fungal mycelia. The rare-earth lanthanide elements (La and Sm) binding increased at initial pH values greater than 5.0, which was also observed for the point of zero charge determination. The maximum La(III) uptake capacity was observed at lower amounts of La(III) ions in solution, decreasing Bioseparations and Downstream Processing
Applied Catalysis A-general, Apr 1, 2018
Highlights Botryosphaeria rhodina MAMB-05 laccase catalyzed synthesis of 3 dimers from 2,6-dime... more Highlights Botryosphaeria rhodina MAMB-05 laccase catalyzed synthesis of 3 dimers from 2,6-dimethoxyphenol at different pH and reaction times Dimers were formed by oxidative coupling via CC (I, II) and CO (III) bonds
Enzyme and microbial technology, 2001
The ascomycete, Botryosphaeria sp, produced two extracellular constitutive laccases (PPO-I and PP... more The ascomycete, Botryosphaeria sp, produced two extracellular constitutive laccases (PPO-I and PPO-II) active toward the substrates: 2, 2 1-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) [ABTS], and 2,6-dimethoxyphenol (DMP), respectively. The production of both laccases increased when the fungal isolate was grown in the presence of veratryl alcohol, and resulted in optimal laccase production (100and 25-fold, respectively) at 40 mM. The effect of aeration on growth and laccase production was studied in baffled flasks, and showed that aeration of the cultures increased the production of both enzymes 4-5 fold in the presence of veratryl alcohol. Both laccases were susceptible to inhibition by azide, acetate and chloride anions. Veratryl alcohol inhibited the laccase-catalyzed polymerization of DMP. Growing cultures of Botryosphaeria sp. produced an exopolysaccharide of the -glucan type whose synthesis was depressed when grown in the presence of veratryl alcohol.
Antonella Carvalho de Oliveira eBooks, Jan 16, 2019
(CIP) (eDOC BRASIL, Belo Horizonte/MG) I34 Impactos das tecnologias nas ciências biológicas e da ... more (CIP) (eDOC BRASIL, Belo Horizonte/MG) I34 Impactos das tecnologias nas ciências biológicas e da saúde 2 [recurso eletrônico] / Organizadora Christiane Trevisan Slivinski.-Ponta Grossa (PR): Atena Editora, 2019.-(Impactos das Tecnologias nas Ciências Biológicas e da Saúde; v. 2) Formato: PDF Requisitos de sistema: Adobe Acrobat Reader Modo de acesso: World Wide Web Inclui bibliografia
Cell Biochemistry and Function
Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)‐β‐d‐glucan (botryosp... more Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)‐β‐d‐glucan (botryosphaeran) have been described in the literature, but its effects on inflammation have not been evaluated. This study aimed to investigate the action of botryosphaeran on experimental mice models of carrageenan‐induced acute pleurisy and acute paw edema, and complete Freund's adjuvant‐induced persistent paw edema. All botryosphaeran doses tested (1.0, 2.5, 5.0, and 10.0 mg/kg birth weight [b.w.], orally administered) reduced leukocyte recruitment, nitric oxide (NO) levels, and protein extravasation in the pleural cavity. Botryosphaeran (5 mg/kg b.w.) did not diminish edema and mechanical hyperalgesia in the paw within 4 h; however, cold allodynia was alleviated within the first 2 h. In the persistent paw inflammation model, the effects of daily oral administration of botryosphaeran (5 mg/kg b.w.) were evaluated over 3 and 7 days. The fungal β‐glucan significantly reduced the levels of t...
Impactos das tecnologias nas ciências biológicas e da saúde 3, 2019
Impactos das Tecnologias nas Ciências Biológicas e da Saúde 3
Queensland in Townsville. • The author reports on the people (lecturers and postgraduate students... more Queensland in Townsville. • The author reports on the people (lecturers and postgraduate students) at the Department of Chemistry at the time, and comments on the themes of research of the Carbohydrate Research Laboratory of Professor Geoffrey Norman Richards group. • The project formed the basis of a Master of Science degree under the guidance of Professor Geoff Richards. • The forages studied included spear grass (Heteropogon contortus)-a native tropical grass, and an introduced legume species known as Townsville lucerne, or Stylo (Stylosanthes humilis)-also confined to tropical regions. These plants represented the major pasture herbages of grazing cattle within the beef industry of tropical northern Australia. • At the time, next to nothing was known about the digestion of polysaccharide components of tropical pasture herbage apart from their dry matter digestibility in beef cattle. • The plant in-situ polysaccharides examined were: starch, pectic substances, hemicelluloses (heteroxylans) and cellulose. • Specific analytical methods were developed to measure each of the polysaccharide components in plant materials and the rumen digested forages.
• The work presented here documents the research the author developed at the Department of Chemis... more • The work presented here documents the research the author developed at the Department of Chemistry, James Cook University at Townsville in North Queensland (AUSTRALIA) on fungal endo-1,4-b-D-xylanases and their modes of action towards several hemicelluloses obtained from tropical grass species, as well as model oligosaccharide substrates of mixed constitution. • The author reports on the people (lecturers and postgraduate students) at the Department of Chemistry and Biochemistry at the time, and comments on the themes of research at the Carbohydrate Research Laboratory of Professor Geoffrey Norman Richards' group. • The project formed the basis of a Ph.D degree under the guidance of Professor Geoff Richards. • The project evolved out of an earlier study on the "Digestion of the polysaccharide components of tropical pasture herbages in the bovine rumen" that the author had conducted at James Cook University during 1969-1972. • The findings arising from that investigation demonstrated that the hemicellulose component of the two tropical pasture forages-Stylosanthes humilis (Townsville lucerne or Stylo), and spear grass (Heteropogon contortus) examined were the least digested of the plant cell wall polysaccharides (pectic substances, cellulose and heteroxylans) within the bovine rumen. • The reason for this was presumed to be due to the "lignin-protection hypothesis". • The author considered whether the molecular structural integrity of the hemicelluloses (heteroxylans) in the forages, which constitute complex chemical structures that are highly branched with sugar appendages attached to the (1®4)-b-xylan backbone chain, may also have influenced the resistance to enzymatic attack by the microbial consortia constituting the rumen flora and fauna species, and their associated enzyme systems.
Polysaccharides of Microbial Origin, Springer Nature, 2021
Botryosphaeran [(1,3)(1,6)-β-D-glucan] is an exopolysaccharide (EPS) produced by the ascomycete B... more Botryosphaeran [(1,3)(1,6)-β-D-glucan] is an exopolysaccharide (EPS) produced by the ascomycete Botryosphaeria rhodina MAMB-05 when cultivated on glucose medium. Botryosphaeran has an unusual chemical structure in the sense that one of its two appendage residues (gentiobiose) attached to the (1,3)-linked backbone chain is rare, the other, glucose, is common to most β-glucans of this type. A family of botryosphaerans is produced on different carbohydrate substrates.
Botryosphaeran is neither mutagenic nor genotoxic, and presents antioxidant, anticlastogenic, hypoglycemic, hypocholesterolemic, and
hypotriglyceridemic activities and reduced the development of Walker-256 bearing tumors and cachexia syndrome in rats. Botryosphaeran exhibited antiproliferation of cancer cells that is associated with cell cycle arrest, apoptosis, necrosis, and oxidative stress in breast carcinoma MCF-7 cells, and cell cycle arrest in human T-lymphocyte tumorigenic cells. Botryosphaeran is commercially used in formulated cosmetic products to promote skin health and treat skin conditions.