Clavulanic acid (CA), a potent beta-lactamase inhibitor, is produced by a filamentous bacterium. Here, the effect of DO and shear, expressed as impeller tip velocity, on CA production was examined. Cultivations were performed in a 4 L fermentor with speeds of 600, 800 and 1,000 rpm and a fixed air flow rate (0.5 vvm). Also, cultivation with automatic control of dissolved oxygen, at 50% air saturation, by varying stirrer speed and using a mixture of air and O(2) (10% v/v) in the inlet gas, and a cultivation with fixed stirrer speed of 800 rpm and air flow rate of 0.5 vvm, enriched with 10% v/v O(2), were performed. Significant variations in CA titer, CA production rate and O(2) uptake-rate were observed. It was also found that the DO level has no remarkable effect on CA production once a critical level is surpassed. The most significant improvement in CA production was related to high stirrer speeds.

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-Clavulanic acid (CA) is a potent inhibitor of β-lactamases, enzymes that are responsible for the hydrolysis of β-lactam antibiotics. It is a secondary metabolite produced by the filamentous aerobic bacterium Streptomyces clavuligerus in submerged cultivations. In the present work clavulanic acid production in batch, fed-batch and continuous bioreactors was studied with the objective of increasing productivity. The operating conditions: temperature, aeration and agitation, were the same in all cases, 28º C, 0.5 vvm and 800 rpm, h -1 in the fed-batch process and 3.5 mg L -1 h -1 in the batch process, suggesting that continuous culture of Streptomyces clavuligerus is a promising strategy for clavulanic acid production.

Chicken hamburgers and steaks coated with breadcrumbs were prepared using pale and normal broiler chicken meat. Analysis of color, cooking loss (CL), texture, meat shrinking (MS), TBA value, microbiological evaluation, and sensorial analysis were performed. Hamburger samples made with pale and normal broiler breast meat did not present differences (p > 0.05) for color, CL, MS, sensorial and microbiological parameters during the storage period evaluated. Regarding texture, some difference (p ≤ 0.05) was noted between the hamburgers after 7, 60, and 120 days of storage. The hamburgers prepared with pale meat (1.92, 1.31, and 1.46, respectively) presented the lowest averages compared to those prepared with normal meat (2.34, 1.85, and 1.73, respectively). For the TBA analysis, samples prepared with pale meat presented the highest values in 90 and 180 days of storage (5.28, 7.78, 8.89, and 5.02) compared to normal meat (2.62, 7.05, 8.08, and 3.89). For the chicken steaks, no differences (p > 0.05) were noted between the products made with normal and pale meat for the TBA, sensorial analysis, and microbiological evaluation during the storage periods studied. Keywords: color; broiler breast; TBA; industrialized. ResumoForam elaborados hambúrgueres e filés empanados com peitos de frango pálidos e normais e foram realizadas as seguintes análises de qualidade: cor, Perda de Peso por Cozimento (PPC), cisalhamento, Encolhimento por Fritura (EF), TBA, avaliação microbiológica e sensorial para os hambúrgueres, e TBA, análise microbiológica e análise sensorial para os filés empanados. As amostras de hambúrgueres elaboradas não diferiram significativamente (p > 0,05) nos parâmetros de coloração, EF, PPC e análise microbiológica e sensorial. Para análise de força de cisalhamento, houve diferença significativa (p ≤ 0,05) entre os hambúrgueres no período de 7, 60 e 120 dias, sendo que os hambúrgueres elaborados com carne pálida (1,92; 1,31 e 1,46, respectivamente) apresentaram as menores médias quando comparados com os de carne normal (2,34; 1,85 e 1,73, respectivamente). Na análise de TBA, as amostras elaboradas com carne pálida também tiveram os maiores resultados com 90 a 180 dias de estocagem (5,28; 7,78; 8,89; 5,02) quando comparadas às de carne normal (2,62; 7,05; 8,08; 3,89). Para os filés empanados, não foram encontradas diferenças significativas (p > 0,05) entre a elaboração com carne de coloração normal e pálida para os parâmetros avaliados. Estes resultados demonstram que a carne pálida pode ser utilizada para a elaboração de produtos industrializados sem causar prejuízos em sua qualidade. Palavras-chave: cor; peito de frango; TBA; industrializados. IntroduçãoA avicultura de corte vem sofrendo constantes modificações ao longo dos últimos anos. Uma delas é a comercialização de cortes que é cada vez maior quando comparada à comercialização da carcaça inteira. Outra forma que cresce intensamente é a venda de produtos industrializados como hambúrgueres, empanados e diversos pratos já preparados e semiprontos para o...