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Biofilms provide cells favorable growth conditions, which have been exploited in industrial biotechnological processes. However, industrial application of the biofilm has not yet been reported in Escherichia coli, one of the most important platform strains, though the biofilm has been extensively studied for pathogenic reasons. Here, we engineered E. coli by overexpressing the fimH gene, which successfully enhanced its biofilm formation under industrial aerobic cultivation conditions. Subsequently, a biofilm-based immobilized fermentation strategy was developed. L-threonine production was increased from 10.5 to 14.1 g/L during batch fermentations and further to 17.5 g/L during continuous (repeated-batch) fermentations with enhanced productivities. Molecular basis for the enhanced biofilm formation and L-threonine biosynthesis was also studied by transcriptome analysis. This study goes beyond the conventional research focusing on pathogenic aspects of E. coli biofilm and represents a successful application case of engineered E. coli biofilm to industrial processes.

The aim of this research was to verify the ability of 15 isolates of Epidermophyton floccosum to perforate hair in vitro and characterize them for pathogenicity factors such as growth at 37ºC and proteinase and phospholipase production. Fourteen isolates perforated hair and from these twelve produced perforating organs. All isolates grew at 37ºC and produced proteinase, but not phospholipase. These results suggest that E. floccosum may be a possible aethiological agent of tinea capitis. O propósito desta pesquisa foi verificar a capacidade de 15 isolados de Epidermophyton floccosum perfurarem cabelo in vitro e caracterizar quanto a fatores de patogenicidade como crescimento a 37ºC e produção de proteinase e fosfolipase. Dos isolados, 14 perfuraram o cabelo tendo 12 formado órgãos de perfuração. Todos os isolados cresceram a 37ºC e secretaram proteinase, mas não fosfolipase. Nossos resultados sugerem E. floccosum como possível agente etiológico de tinea capitis.