Assessment of Levan Production from Sucrose by Zymomonas mobilis CCT 4494

bonds. It can be found in many plants and microbial products, and it has many applications in different industrial fields, such as foods and pharmaceuticals. The aim of this study was to analyze levan production from sucrose by Zymomonas mobilis CCT 4494. A 24-1 fractional design was carried out to evaluate the effects of pH, temperature, sucrose concentration and time. The statistical analysis (p<0.10) showed that the effect of the sucrose concentration was the most important influence on the levan concentration followed by the effect of the temperature. The best levan biosynthesis condition was at 25 ºC, with initial pH value of 4.5, 250 g L-1 of sucrose concentration during 72 h of fermentation. Furthermore, highest levan production was 7.6 g L-1, at 25 °C with sucrose concentration of 250 g L-1. DOI: http://dx.doi.org/10.17807/orbital.v11i6.122

Assessment of Levan Production from Sucrose by Zymomonas mobilis CCT 4494

bonds. It can be found in many plants and microbial products, and it has many applications in different industrial fields, such as foods and pharmaceuticals. The aim of this study was to analyze levan production from sucrose by Zymomonas mobilis CCT 4494. A 24-1 fractional design was carried out to evaluate the effects of pH, temperature, sucrose concentration and time. The statistical analysis (p<0.10) showed that the effect of the sucrose concentration was the most important influence on the levan concentration followed by the effect of the temperature. The best levan biosynthesis condition was at 25 ºC, with initial pH value of 4.5, 250 g L-1 of sucrose concentration during 72 h of fermentation. Furthermore, highest levan production was 7.6 g L-1, at 25 °C with sucrose concentration of 250 g L-1. DOI: http://dx.doi.org/10.17807/orbital.v11i6.122

Sulfonated (1→6)-β-D-Glucan (Lasiodiplodan): Preparation, Characterization and Bioactive Properties

U radu su proizvedeni sulfonirani derivati β-D-glukana iz gljive Lasiodiplodia theobromae MMPI, nazvani lasiodiplodan (LAS-S), s različitim stupnjevima supstitucije (1,61; 1,42; 1,02 i 0,15), te su okarakterizirani pomoću FTIR spektroskopije i skenirajuće elektronske mikroskopije (SEM). Ispitani su toplinska svojstva, topljivost, te antimikrobni, antioksidacijski i citotoksički učinak derivata. Uspješnost sulfonacije provjerena je FTIR analizom, pri čemu su dobivene specifične vrpce na 1250 cm-1 (S=O, jaki signal za asimetričnu vibraciju rastezanja dvostruke veze) i 810 cm-1 (C-O-S, signal za simetričnu vibraciju povezan s prisustvom C-O-SO3 skupine) u sulfoniranim uzorcima. SEM analizom je potvrđeno da sulfonacija pospješuje morfološke promjene na površini biopolimera, uz pojavu heterogenih fibrilarnih struktura na površini nakon kemijske modifikacije. Sulfonirani je lasiodiplodan imao veliku toplinsku stabilnost, a zbog oksidacije pri gotovo 460 °C opažen je gubitak mase. Sulfonacijom je povećana topljivost lasiodiplodana i njegova antimikrobna aktivnost, osobito spram kvasca Candida albicans i bakterije Salmonella enterica Typhimurium. Prirodni je lasiodiplodan bolje uklanjao ione OH˙, dok je sulfonirani bolje uklanjao ione željeza (FRAP potencijal). Ni prirodni ni sulfonirani lasiodiplodan nisu imali citotoksični učinak na divlje tipove i mutante kvasca Saccharomyces cerevisiae. Uzorci s većim stupnjem supstitucije (1,42 i 1,61) imali su slabije svojstvo indukcije oksidacijskog stresa.Sulfonated derivatives of lasiodiplodan (LAS-S) with different degrees of substitution (1.61, 1.42, 1.02 and 0.15) were obtained and characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal and solubility analyses. Antimicrobial, antioxidant and cytotoxic potential were also assessed. The sulfonation was confirmed by FTIR analysis with specific bands at 1250 cm–1 (S=O, strong asymmetrical stretching vibration) and at 810 cm–1 (C-O-S, symmetrical vibration associated with the C-O-SO3 group) in the sulfonated samples. SEM demonstrated that sulfonation promoted morphological changes on the surface of the biopolymer with heterogeneous fibrillary structures appearing along the surface following chemical modification. LAS-S showed high thermal stability, with mass loss due to oxidation at temperatures close to 460 °C. Sulfonation increased the solubility of LAS, and in addition, increased the antimicrobial activity, especially against Candida albicans (fungicidal) and Salmonella enterica Typhimurium (bacteriostatic). Native lasiodiplodan (LAS-N) showed higher OH˙ removal capacity, while LAS-S had higher ferric ion reducing antioxidant power (FRAP) potential. LAS-N and LAS-S did not demonstrate lethal cytotoxicity against wild and mutant strains of Saccharomyces cerevisiae. Samples with higher degree of substitution (1.42 and 1.61) showed lower potential to induce oxidative stress

Perfil microbiano, físico-químico e análise das boas práticas de fabricação (BPF) de queijos minas frescal e ricota

Alguns queijos frescos como o Minas frescal e a ricota, apresentam elevada atividade de água e diversidade nutricional, fatores que propiciam a proliferação e o desenvolvimento de microbiota oportunista, prejudicando a qualidade e a integridade destes produtos. Diversos microrganismos são propostos como bioindicadores de contaminação da matéria-prima e/ou do produto pronto para o consumo. Para evitar quaisquer fontes de contaminação é imprescindível a adoção de Boas Práticas de Fabricação (BPF), as quais podem ser avaliadas por meio da aplicação do formulário check-list. Nesse contexto, este estudo objetivou avaliar as condições higiênico-sanitárias e adequações quanto às BPF, em uma indústria de laticínios de pequeno porte, produtora de queijos Minas frescal e ricota, localizada em São José do Rio Preto – SP, por meio do monitoramento microbiológico, físico-químico, e aplicação de check-list. Foram realizadas análises, conforme o fluxograma de fabricação, nas seguintes etapas: água, leite pasteurizado, coalho, massa, soro, superfície palmar dos manipuladores e tanque de coagulação, e queijos Minas frescal e ricota logo após o processamento (t0) e com cinco dias de vida de prateleira (t5). Tais etapas foram monitoradas quanto à qualidade microbiológica, por meio da determinação do Número Mais Provável (NMP) de coliformes totais e termotolerantes; contagem de Staphylococcus coagulase positiva e bactérias aeróbias mesófilas; pesquisa de Escherichia coli, Salmonella spp. e Listeria monocytogenes. A contagem de bactérias aeróbias mesófilas foi efetuada apenas nas amostras de água. As análises de determinação do NMP de coliformes totais, termotolerantes foram realizadas para todas as amostras. A contagem de Staphylococcus aureus, pesquisa de Escherichia coli e de Salmonella spp., foram efetuadas para todas as amostras citadas...Some fresh cheeses as Minas frescal and ricota present high water activity and nutritional diversity, factors that permit the proliferation and the development of opportunist microrganisms, damaging the quality and integrity of these products. Several microrganisms are proposed as bioindicators of raw material and/or product ready for consumption contamination. To avoid any contamination source it`s indispensable to adopt Good Manufacturing Practices (GMP), which may be evaluated by application of checklist form. According to the presented, this study had the objective of evaluate the hygienic sanitary conditions and adequacies, in relation to the GMP, at a small dairy industry; which produces ricota and Minas frescal cheeses, located in São José do Rio Preto - SP by the physical-chemical and microbiological monitoring and check-list application. The analyses were done according to the following production stages: water, pasteurized milk, curd, mass, sour, manipulator hands, coagulation tank, ricota and Minas frescal cheese right after the processing (t0) and with five days of shelf-life (t5). Such stages were monitored in relation to the microbiological quality by the determination of the Most Probable Number (MPN) of total and thermotolerant coliforms; mesophilic aerobic bacteria and Staphylococcus aureus counting; research of Escherichia coli, Salmonella spp. and Listeria monocytogenes. The counting of mesophilic aerobic bacteria was done only in the water samples. The analyses of the determination of the MPN of total and thermotolerant coliforms were done for all samples. The counting of Staphylococcus aureus, Escherichia coli and Salmonella spp. research were done for all samples except water. The analysis of Listeria monocytogenes was done only for Minas frescal and ricotta cheeses. For the water analysis it was verified that 3 samples (25%) presented... (Complete abstract click electronic access below)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Avaliação de suportes para a imobilização de Zymomonas mobilis CCT 4494 visando à produção de etanol e levana

Zymomonas mobilis is considered to have high biotechnological potential for ethanol and levan production, because it produces little biomass and shows good tolerance to ethanol concentrations. However, this efficiency can be decreased if the free cells are exposed to unfavorable conditions during conventional fermentations. Cell immobilization is an alternative to solve this problem and offers numerous advantages such as higher cell concentrations, greater stability and improved production. Thus the aim of this work was to select a suitable support for the immobilization of Zymomonas mobilis in order to increase the production of ethanol and levan from sucrose as the carbon source. The optimum values for ethanol and levan production were determined using response surface methodology (RSM). The first experiment was a 2(5-2) design with the following independent variables: sucrose concentration, pH, incubation time, temperature and agitation of the culture medium. Based on the best conditions observed in the 2(5-2) experiment, reuse of the support was evaluated during 12 days of fermentation. Ethanol production was determined by microdiffusion and the levan production on fructose units after acid hydrolysis. The biomass was determined by optical density at 570 nm and microbial growth on the support was verified by scanning electron microscopy. In the 2(5-2) experiment the loofa sponge was the best support for immobilization with the highest values for immobilized biomass (2.95 g/L); levan production (24.9 g/L) and ethanol production (50.95 g/L). In the immobilization support reuse experiments in batch fermentations, all the supports evaluated could be reused for 12 cycles, with the exception of chitosan beads. Sugarcane bagasse was shown to be the best substrate for microbial adhesion (3.23 g/L) and for levan (32.13 g/L) and ethanol production (36.50 g/L). Thus the loofa sponge and sugarcane bagasse represented the most promising support ...A bactéria Zymomonas mobilis é considerada um microrganismo com alto potencial biotecnológico para a produção de etanol e levana, por apresentar baixa produção de biomassa e alta tolerância a elevadas concentrações de etanol. Apesar disso, sua eficiência pode ser prejudicada, devido a exposição das células livres a condições desfavoráveis durante os processos fermentativos convencionais. A utilização de células imobilizadas é uma alternativa para solucionar tais problemas, pois oferece inúmeras vantagens como maior concentração celular, maior estabilidade e conseqüentemente maior produção. Diante disso, o objetivo deste trabalho, foi selecionar um suporte adequado para a imobilização de Zymomonas mobilis visando aumentar a produção de etanol e levana empregando sacarose como fonte de carbono. Os suportes avaliados foram: alginato, quitosana, bucha vegetal e bagaço de cana. Os melhores parâmetros para a produção de etanol e levana, foram determinados utilizando a metodologia de superfície de resposta (MSR). O primeiro experimento realizado foi 2(5-2) com as variáveis independentes: concentração de sacarose; pH; tempo de incubação; temperatura e agitação do meio de cultura. Com base nas melhores condições observadas no experimento 2(5-2) foi avaliada a capacidade de reutilização dos suportes em fermentações subseqüentes durante 12 dias. A produção de etanol foi determinada pelo método de microdifusão e a levana foi determinada indiretamente em unidades de frutose após hidrólise ácida. A biomassa foi determinada por densidade ótica a 570 nm e a fixação do microrganismo no suporte foi confirmada por microscopia eletrônica de varredura. No experimento 2(5-2), verificou-se que o melhor suporte de imobilização foi a bucha vegetal, a qual apresentou os maiores valores de biomassa imobilizada (2,95 g/L); produção de levana (24,9 g/L) e etanol (50,95 g/L). Para os experimentos com ...Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Avaliação das boas práticas de fabricação em linha de processamento de queijos Minas frescal e ricota

In order to assure the maintenance of foods integrity and quality, for avoiding chemical, physical or biological contamination, it is essential to follow the Good Manufacturing Practices (GMP). Among the techniques used for evaluating GMP there is the observational analysis carried out by means of a check-list form application. The present study evaluated the suitability of GMP in a dairy industry producer of Minas fresh and ricotta cheeses, located in São José do Rio Preto, SP, by applying a check-list form. A significant improvement in conformity was evidenced, increasing from 43% to 78%. Neither the blocks related to the handlers nor the existing documentation in the company showed any improvements, as poor conditions unchanged. All of the other evaluated blocks showed significant improvement after applying the GMPrelated corrective measures. Based on these findings, the observance of corrective measures by the dairy industry on dairy products, physical environment, GMP, and handlers training was crucial for assuring the improvements and to increase the product quality and consumers safety.Para a manutenção da integridade e qualidade dos alimentos e evitar contaminações de origem química, física ou biológica, é imprescindível a adoção de Boas Práticas de Fabricação (BPF). Dentre as técnicas utilizadas para a avaliação das BPF, há a análise observacional por meio da aplicação do formulário checklist. Nesse contexto, este estudo avaliou as adequações quanto às BPF em uma indústria de laticínios de pequeno porte produtora de queijos Minas frescal e ricota, localizada em São José do Rio Preto - SP, por meio da aplicação do formulário check-list. Pela avaliação realizada no laticínio, verificou-se importante melhora nos critérios de conformidade, com aumento de 43% para 78%. Os blocos relacionados aos manipuladores e à documentação existente na empresa não apresentaram melhorias, pela evidência de más condições nessas questões. Todos os demais blocos avaliados apresentaram importante melhora após a adoção de ações corretivas relativas às BPF. Diante destas observações, a adoção de ações corretivas pelo laticínio com relação ao ambiente físico, BPF e treinamentos de manipuladores são essenciais para garantir as melhorias observadas, com aumento da qualidade dos produtos e segurança dos consumidores. Palavras-chave. produtos lácteos, segurança alimentar, controle de qualidade, lista de chegagem

Ethanol and Levan production by sequential bath using Zymomonas mobilis immobilized on alginate and chitosan beads

Current study evaluates ethanol and levan production using Zymomonas mobilis immobilized on alginate and chitosan beads and assesses the capacity of the beads for reuse in sequential fermentations. Two experiments were carried out: In the first experiment 2(5-2) design evaluated the following independent variables: sucrose concentration; pH; incubation time; temperature and agitation. In the second experiment, based on the best conditions observed in 2(5-2), the capacity of the immobilization support reuse in subsequent fermentations was evaluated for 12 days. In experiments using fractionated factorial experimental design 2(5-2) the best results by immobilized biomass (2.6 g L-1) and immobilization efficiency was shown by alginate and chitosan beads showed only 0.22 g L-1. Chitosan support provided the best rates to levan production (8.90 g L-1). Alginate support showed the highest values by ethanol production (93.4 g L-1). In batch sequential fermentation, re-using immobilization support, alginate support was efficient by maintaining the cellular viability on immobilized support (0.94 g L-1), levan production (21.11 g L-1) and ethanol production (87.21 g L-1). Chitosan support was inadequate for sequential batches since the beads dissolved after the second cycle.