-
Scientific Reports Dec 2020Microbial induced calcite precipitation (MICP) based on ureolysis has a high potential for many applications, e.g. restoration of construction materials. The...
Microbial induced calcite precipitation (MICP) based on ureolysis has a high potential for many applications, e.g. restoration of construction materials. The gram-positive bacterium Sporosarcina pasteurii is the most commonly used microorganism for MICP due to its high ureolytic activity. However, Sporosarcina pasteurii is so far cultivated almost exclusively in complex media, which only results in moderate biomass concentrations at the best. Cultivation of Sporosarcina pasteurii must be strongly improved in order to make technological application of MICP economically feasible. The growth of Sporosarcina pasteurii DSM 33 was boosted by detecting auxotrophic deficiencies (L-methionine, L-cysteine, thiamine, nicotinic acid), nutritional requirements (phosphate, trace elements) and useful carbon sources (glucose, maltose, lactose, fructose, sucrose, acetate, L-proline, L-alanine). These were determined by microplate cultivations with online monitoring of biomass in a chemically defined medium and systematically omitting or substituting medium components. Persisting growth limitations were also detected, allowing further improvement of the chemically defined medium by the addition of glutamate group amino acids. Common complex media based on peptone and yeast extract were supplemented based on these findings. Optical density at the end of each cultivation of the improved peptone and yeast extract media roughly increased fivefold respectively. A maximum OD600 of 26.6 ± 0.7 (CDW: 17.1 ± 0.5 g/L) was reached with the improved yeast extract medium. Finally, culture performance and media improvement was analysed by measuring the oxygen transfer rate as well as the backscatter during shake flask cultivation.
Topics: Bacterial Physiological Phenomena; Carbon; Culture Media; Hydrogen-Ion Concentration; Microbiological Techniques; Nutritional Requirements; Sporosarcina
PubMed: 33384450
DOI: 10.1038/s41598-020-79904-9 -
Molecules (Basel, Switzerland) Jun 2020The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields...
The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields and facile synthesis of nanoparticles. The green synthesis provides the coating or capping of biomolecules on nanoparticles surface, which confer their biological activity. In this study, we report green synthesis of silver nanoparticles (AgNPs) by an environmental isolate; named as AgNPs1, which showed 100% 16S rRNA sequence similarity with UV/visible analysis (UV/Vis), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stable nature of nanoparticles was studied by thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS). Further, these nanoparticles were tested for biofilm inhibition against and . The AgNPs showed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.12 µg/mL and 6.25 µg/mL for , and 1.56 µg/mL and 3.12 µg/mL for , respectively.
Topics: Biofilms; Escherichia coli; Green Chemistry Technology; Metal Nanoparticles; Planococcaceae; Pseudomonas aeruginosa; Silver
PubMed: 32560208
DOI: 10.3390/molecules25122783