Recombinant Escherichia coli BL21-pET28a-egfp Cultivated with Nanomaterials in a Modified Microchannel for Biofilm Formation

Abstract

The application of whole cells as catalytic biofilms in microchannels has attracted increasing scientific interest. However, the excessive biomass formation and structure of biofilms in a reactor limits their use. A microchannel reactor with surface modification was used to colonize recombinant Escherichia coil BL21-pET28a-egfp rapidly and accelerated growth of biofilms in the microchannel. The segmented flow system of ‘air/culture medium containing nanomaterials’ was firstly used to modulate the biofilms formation of recombinant E. coil; the inhibitory effects of nanomaterials on biofilm formation were investigated. The results indicated that the segmental flow mode has a significant impact on the structure and development of biofilms. Using the channels modified by silane reagent, the culture time of biofilms (30 h) was reduced by 6 h compared to unmodified channels. With the addition of graphene sheets (10 mg/L) in Luria-Bertani (LB) medium, the graphene sheets possessed a minimum inhibition rate of 3.23% against recombinant E. coil. The biofilms cultivated by the LB medium with added graphene sheets were stably formed in 20 h; the formation time was 33.33% shorter than that by LB medium without graphene. The developed method provides an efficient and simple approach for rapid preparation of catalytic biofilms in microchannel reactors.

The Transcription Factor CsgD Contributes to Engineered Escherichia coli Resistance by Regulating Biofilm Formation and Stress Responses

“…Subsequently, 4% glutaraldehyde was added to a 12-well plate and placed in a refrigerator at 4 °C overnight. Then, the 4% glutaraldehyde was removed, and the biofilm adsorbed on the glass slide was stained with SYBR Green I dye for 30 min, which was used for fluorescence inversion microscopy (Eclipse TS100, Nikon, Tokyo Metropolis, Japan) and laser focusing scanning microscopy (LEXTOLS4000, Olympus, Tokyo, Japan) observation according to the method of Chen and Zhu et al [ 5 , 50 ]. In addition, ethanol was used to dehydrate the biofilm fixed with 4% glutaraldehyde and freeze-dried for scanning electron microscope (Regulus-8100, Hitachi, Tokyo, Japan) observation [ 51 ].…”