Very high gravity bioethanol revisited: main challenges and advances

Over the last decades, the constant growth of the world-wide industry has been leading to more and more concerns with its direct impact on greenhouse gas (GHG) emissions. Resulting from that, rising efforts have been dedicated to a global transition from an oil-based industry to cleaner biotechnological processes. A specific example refers to the production of bioethanol to substitute the traditional transportation fuels. Bioethanol has been produced for decades now, mainly from energy crops, but more recently, also from lignocellulosic materials. Aiming to improve process economics, the fermentation of very high gravity (VHG) mediums has for long received considerable attention. Nowadays, with the growth of multi-waste valorization frameworks, VHG fermentation could be crucial for bioeconomy development. However, numerous obstacles remain. This work initially presents the main aspects of a VHG process, giving then special emphasis to some of the most important factors that traditionally affect the fermentation organism, such as nutrients depletion, osmotic stress, and ethanol toxicity. Afterwards, some factors that could possibly enable critical improvements in the future on VHG technologies are discussed. Special attention was given to the potential of the development of new fermentation organisms, nutritionally complete culture media, but also on alternative process conditions and configurations.This work has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitive ness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Pro gramme (Lisboa 2020) and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and has been supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 and through Project EcoTech (POCI-01-0145- FEDER-032206/ FAPESP 2018/07522-6) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. The authors also acknowledge the financial support of Research Support Foundation of the state of Minas Gerais-FAPEMIG, National Counsel of Technological and Scientific Development-CNPq and Coordination for the Improvement of Higher Education Personnel-CAPES (Finance Code 001).info:eu-repo/semantics/publishedVersio

Estudo da produção de beta-galactosidase por fermentação de soro de queijo com Kluyveromyces marxianus

A hidrólise enzimática da lactose por beta-galactosidase desempenha importante papel no processamento de produtos lácteos, como na obtenção de leite com baixo teor de lactose para consumo por indivíduos intolerantes à mesma e na prevenção da cristalização em produtos de laticínio. Neste trabalho, a enzima beta-galactosidase foi produzida pelo cultivo do microrganismo Kluyveromyces marxianus, em meio de cultura à base de soro de queijo em diferentes concentrações iniciais de lactose e extrato de levedura, de acordo com um planejamento fatorial. As fermentações foram conduzidas em incubador rotativo a 150rpm, a 30°C e pH inicial 5,5. A concentração celular inicial foi de 10(7) células/mL. Para a extração da enzima beta-galactosidase, foi realizada autólise das células utilizando como solvente o clorofórmio em tampão fosfato. No meio de cultura enriquecido com (NH4)2SO4, KH2PO4 e MgSO4, nas concentrações iniciais de lactose e de extrato de levedura iguais a 50g/L e 12g/L, respectivamente, obteve-se uma atividade de 28,0UGl/mL e uma concentração celular máxima de 5,3g/L

Improvement of recovered activity and stability of the Aspergillus oryzae β-galactosidase immobilized on duolite A568 by combination of immobilization methods

The immobilization and stabilization of Aspergillus oryzae β-galactosidase on DuoliteA568 was achieved using a combination of physical adsorption, incubation step in buffer at pH 9.0 and cross-linking with glutaraldehyde and in this sequence promoted a 44% increase in enzymatic activity as compared with the biocatalyst obtained after a two-step immobilization process (adsorption and cross-linking). The stability of the biocatalyst obtained by three-step immobilization process (adsorption, incubation in buffer at pH 9.0 and cross-linking) was higher than that obtained by two-steps (adsorption and cross-linking) and for free enzyme in relation to pH, storage and reusability. The immobilized biocatalyst was characterized with respect to thermal stability in the range 55-65 °C. The kinetics of thermal deactivation was well described by the first-order model, which resulted in the immobilized biocatalyst activation energy of thermal deactivation of 71.03 kcal/mol and 5.48 h half-life at 55.0 °C

Solid-phase amination of Geotrichum candidum lipase: ionic immobilization, stabilization and fish oil hydrolysis for the production of Omega-3 polyunsaturated fatty acids

In this paper, solid-phase chemical amination was applied to enrich the surface of Geotrichum candidum lipase (GCL) with amino groups. The aminated enzyme was slightly thermostabilized and showed a different activity profile at different pH in relation to the non-aminated enzyme. Furthermore, the chemical modification allowed the enzyme to be rapid and easily immobilized on carboxymethyl and sulfopropyl agarose-based supports. The cationically exchanged derivatives presented higher thermostability and higher stability at alkaline pH than the soluble aminated enzyme. In addition, the carboxymethyl derivative was 5.4-, 8.7- and 9.1- and the sulfopropyl derivative was 6.6-, 11.7- and 10.7-fold more stable than the free aminated enzyme in methanol, propanol and cyclohexane, respectively. The ionic derivatives were applied for fish oil hydrolysis in organic aqueous medium at 37 °C. After 72 h of reaction, Omega-3 production corresponded to 354 and 482 μM using the carboxymethyl and sulfopropyl derivatives, respectively. These derivatives resulted, respectively, in 2.4- and 3.2-fold increased fish oil hydrolysis when compared to the soluble aminated lipase. After the reaction, carboxymethyl derivative presented 6.65 U per gram of support and sulfopropyl derivative showed 7.85 U per gram of support, making them attractive for industrial application.The authors wish to thank CAPES (Brazil) for financial support through the PDSE Program (BEX 14174/13-8) and the “Instituto de Investigación en Ciencia de la Alimentación” (CIAL) for supporting this project.Peer Reviewe

Seguimento de 9 anos da bioprótese valvular cardíaca de pericárdio bovino IMC-Biomédica: estudo multicêntrico Nine year follow-up of the bovine pericardial prosthetic valve IMC-Biomedica: a multicenter study

De dezembro de 1977 a novembro de 1986, foi usado o bioenxerto valvular cardíaco de pericárdio bovino IMC-Biomédica na posição mitral, em 798 pacientes, com idade média de 42 anos. Os 722 pacientes sobreviventes foram observados por um período de até 9 anos, representando 27036 meses, ou 2253 anos. O estudo indicou um índice de sobrevida de 66% para os adultos e 69% para os jovens, sendo de 94% e 80% o índice de sobrevida para os adultos e jovens, respectivamente, com pós-operatório de 5 anos. A freqüência das complicações diante da amostra analisada foi: 0,4% de rotura do tecido; 0,4% de vazamento paravalvular; 2,7% de acidente vascular cerebral; 3,2% de endocardite infecciosa; 4,4% de calcificação. A curva atuarial de calcificação entre os anos de 1978 e 1982 (Grupo I) mostrou 94% dos adultos e 12% dos jovens livres dessa complicação. Por outro lado, de 1982 a 1986 (Grupo II), esse índice subiu para 99,0% entre os adultos e 92,0% para os jovens. Deste modo, concluímos que a nossa opção pela bioprótese de pericárdio bovino foi apropriada, visto que 96% dos pacientes estiveram livres de complicações fatais relacionadas à bioprótese, o que significa que, em 9 anos, o potencial da bioprótese foi apenas de 4%.A mitral pericardial bioprosthetic valve IMC-Biomedica was implanted in a consecutive series of 798 patients with mean age of 52 years, from December 1977 to November 1978. The 722 patients who survived operation were observed during a period of 9 years (mean 27036 months or 2253 years). Actuarial studies indicated an expected survived rate at 9 years of 66% for adult patients and 68% for younger patients. The probability of complications were the following: rupture 0.4; perivalvar leak 0.4%; thromboembolysm 2.7%; endocarditis 3.2%; calcification 4.4%. The actuarial freedom from calcification between 1977 to 1982 (Group I) was 94.0% to adults and 12.0% to younger patients. On the other hand, between 1982 to 1986 (Group II) the actuarial analysis of calcification showed that 99.0% adults and 92.0% younger patients were free from this complication. Hence we believe that our option for the pericardial bioprosthetic valve was appropriate because 96.0% patients were free of complications deaths with the valve; this means that in 9 years the bioprosthetic lethal potential was only 4.0%