Overproduction of clavulanic acid by extractive fermentation

Background: Clavulanic acid is an important beta-lactamase inhibitor produced as a secondary metabolite by the actinomycete Streptomyces clavuligerus. Clavulanic acid is chemically unstable; therefore, it is degraded during bacterial cultivation. In this work, the adsorbents clinoptilolite, activated carbon, calcined hydrotalcite, and Amberlite IRA 400 anionic exchange resin were studied in terms of their ability to adsorb clavulanic acid during extractive fermentation, in order to prevent product degradation and avoid product concentrations reaching inhibitory levels. Adsorption assays were used to investigate the effect of pH, and the decrease in the clavulanic acid concentration in the culture broth was measured for each adsorbent. Results: IRA 400 was found to be most effective, with 78% adsorption of clavulanic acid. The maximum production of clavulanic acid in Erlenmeyer flask cultures increased 86% in terms of mass of CA, and 248% in cumulative CA concentration, with the use of Amberlite IRA 400 as adsorbent in extractive fermentation, compared to control fermentation performed without product removal. Conclusions: The results indicated that extractive fermentation using a solid phase could be an important way of enhancing clavulanic acid titers. It was also possible to show that clavulanic acid acts as an inhibitor of its own synthesis

DESAFIOS RELACIONADOS À PRODUÇÃO E APLICAÇÃO DAS ENZIMAS CELULOLÍTICAS NA HIDRÓLISE DA BIOMASSA LIGNOCELULÓSICA

The second generation (2G) ethanol obtained from lignocellulosic biomass has been considered as a potential alternative source of energy for the transportation sector. However, the technologies to convert lignocellulose into fermentable sugars still face several challenges. One of the major challenges of this process is related to the cost of the cellulolytic enzymes. Thus, the development of bioprocesses for enzyme production and strategies to increase the final yield of the enzymatic hydrolysis reactions are required to ensure the economic feasibility of the biomass conversion process. In this review, it is discussed the progress related to fungal enzyme technology over the past few years with major emphasis on the biocatalysts needed for cellulose degradation as well as on cultivation strategies for the production of enzymes on-site. The potential of applying secretome analysis as a tool for the characterization of the enzymatic complexes and some limitations on the use of enzymatic cocktails in the saccharification step, such as the unproductive adsorption of enzymes onto lignin are also discussed in light of the recent literature

Influence of free amino acids on clavulanic acid production by Streptomyces clavuligerus in synthetic medium

The effect of nitrogen source on clavulanic acid production was investigated in shake flasks. Media containing asparagine plus one of several different amino acids or a combination of two amino acids was tested. The best result, ca. 180 mg/L clavulanic acid, CA, in 60 h, was obtained with the lysine-tyrosine pair In an aerated and agitated fermentor this medium led to CA concentrations of ca. 210 mg/L, a remarkable production for synthetic medium utilization. Amino acids analysis during cultivation indicated that, while asparagine was consumed rapidly, lysine and tyrosine were metabolized slowly, promoting CA production

Comparisons between continuous and batch processing to produce clavulanic acid by Streptomyces clavuligerus

The aim of the present work was to compare CA production in continuous culture with and without cell recycling and in batch process by Streptomyces clavuligerus. Continuous cultivations with high cell concentration using cell recycling were performed utilizing a hollow fiber ultrafiltration module to separate cells from the filtrate broth. The continuous cultures without cell recycling and the batch cultivations were performed conventionally. The highest productivity was attained in the continuous cultivation with cell recycling (22.2 mg.L-1.h-1). The highest CA concentration was obtained in the batch process (470 mg.L-1.h-1)

Evaluation of different media for the production of cephalosporins by Streptomyces clavuligerus ATCC 27064

The aim of this work was to compare the composition of a complex and soluble culture medium to eight other media described in the literature through the batch cultivation in a conventional bench-scale bioreactor for the production of cephamycin C by a wild strain of Streptomyces clavuligerus. The proposed medium resulted in an antibiotic production 1.5 to 7.5 times higher than the other culture media.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES