Microsegmented flow-assisted miniaturized culturing for isolation and characterization of heavy metal-tolerant bacteria

Abstract

Soils are complex ecosystem, and their function in the environment is mainly determined by the microbial communities. Metal-tolerant micro-organisms have an important function in the formation of soil and the development of microbial communities in all areas where heavy metals are released by natural erosion processes or by human activities. The investigation of dose-dependent growth and behaviour is an essential part of the search for heavy metal-tolerant microorganism communities and their characterization. In this study, next-generation sequencing was used for the analysis of soil sample and reduced communities and droplet-based microfluidics was used to assess the growth behaviour of unknown bacterial communities and single strains in response to different heavy metal ions. Highly resolved dose-response functions of the bacterial communities reflect the specific character in their concentration-dependent response to different culture media and heavy metals of copper, nickel and cobalt. Besides the characterization of community responses, they allowed to characterize newly isolated strains. Concentration-dependent growth patterns of the micro-organisms in the droplets could be observed. The investigation demonstrates the potential of droplet-based microfluidics for miniaturized eco-toxicological studies and their suitability for the discovery of novel strains with special tolerance features.

Microfluidically supported characterization of responses of Rhodococcus erythropolis strains isolated from different soils on Cu-, Ni-, and Co-stress

“…The isolates of R. erythropolis from our laboratory collection were used in experiments to determine the tolerance against Cu 2+ , Ni 2+ , and Co 2+ . R. erythropolis were isolated from various soil samples (see Table 1 ) with either the droplet-based selection procedure (SS procedure) or the MTP-based diversity exploitation procedure (MTP procedure), which was already described in our previous work [ 30 ] (see Fig. 1 ).…”

“…The obtained cultures were characterized by Sanger sequencing after re-cultivation and successful isolation. The procedure for sample preparation for Sanger sequencing and sequence data analysis was describe in our previous work [ 30 ]. We defined that for identification on species level, a percent match of at least 99% similarity and for identification on genus level, a percent match of at least 97% are required.…”

Microtoxicology by microfluidic instrumentation: a review

“…A similar platform was utilized for identifying heavy metal tolerant bacteria from soil samples susceptible to copper, nickel, and cobalt ions. 126 Besides investigating toxic effects on bacteria, the characterization of the concentration-dependent response of eukaryotic organisms to toxins is a central task of toxicology. Therefore, the effect of toxins on eukaryotic microorganisms and multicellular organisms has to be studied.…”

“…A similar platform was utilized for identifying heavy metal tolerant bacteria from soil samples susceptible to copper, nickel, and cobalt ions. 126…”

Induction of embryogenic development in haploid microspore stem cells in droplet-based microfluidics

“…Despite successful application of microfluidics for the separation and analysis of microorganisms from complex soil microbial communities 7,8 or some eukaryotes like chlorella 9 even cells of multicellular organisms 10 as well as several applications of chip-based microfluidic devices for plant cells, [11][12][13] droplet-based microfluidics has not yet been applied for microspore in vitro culture.…”