Yield cultivation of magnetotactic bacteria and magnetosomes: A review

Abstract

Magnetotactic bacteria (MTB) have started to be employed for the biosynthesis of magnetic nanoparticles, due to the rapidly increasing demand for nanoparticles in biomedical, biotechnology and environmental protection. MBT are the group of prokaryotes that have the ability to produce bio-magnetic minerals or bio-magnetic crystals of either magnetite (Fe O ) or greigite (Fe S ) in numerous shapes and size ranges, known as magnetosomes (MS). MS compel MTB to respond to the applied external magnetic field. However, it is extremely difficult to grow MTB and produce high yield of MS under artificial environmental conditions, thus creating a major hurdle to relocate MTB technology from laboratory scale to industrial or commercial level. Therefore, to best of our knowledge this review is the first attempt to highlight existing research developments about the laboratory scale and mass production of MS by MTB. Moreover, the optimum culture media and environmental conditions used for the cultivation of MTB were also considered. Finally, future research is encouraged for the improvement of MS yield which will result in the development of advanced nanotechnology/magnetotechnology.

Effects of Environmental Conditions on High-Yield Magnetosome Production by Magnetospirillum gryphiswaldense MSR-1

“…Unlike the chemical synthesis of other nanocrystals, magnetosomes are synthesized via unique features, including a perfect crystallographic appearance, a narrow and single magnetic domain in nanosize range with a permanent magnetization, and the formation of a biocompatible lipid bilayer around each mineral particle [2,[11][12][13] , which bring about an exceptional importance in biotechnological applications of magnetic nanoparticles such as nuclear magnetic resonance, cell separation assays as drug carriers, and destruction of tumor cells by hyperthermia [14][15][16][17][18] . Since 1991, several applications including carriers for enzymes [19] , nucleic acids [8,20] , and antibodies [19] as well as anticancer drugs [8,9,21] have been reported for bacterial magnetosomes.…”

“…However, because of the difficulty in growing magnetotactic bacteria and the low-yield production of magnetosomes, these applications have not been extended to commercial scale [10,13] . Various kinds of culture media such as the optimized flask medium (OFM), large-scale medium, magnetic spirillum growth medium, and optimized growth medium have been developed to fulfill the requirements of magnetotactic bacteria [11] . Adjustment of oxygen, temperature, and redox potential have been demonstrated to be remarkably effective in magnetosome production and magnetotactic bacterial yield in fed-batch flasks and bioreactors [11,12,22] .…”

Sorption of cationic malachite green dye on phytogenic magnetic nanoparticles functionalized by 3-marcaptopropanic acid

“…1 However, some specic requirements, such as the need for high pressure and temperature, the employment of toxic and hazardous capping and reducing agents to control the size, shape and composition of the metal oxide NPs, the typically long reaction times and the abrasive reaction environments are the major disadvantages in utilizing these synthesis routes. 1,2 Moreover, the disintegration/ aggregation of these metal oxides-based NPs into chain-like structures is one of the main and well-known limitations and can cause a reduction in their surface area to volume ratio and interfacial free energy, thus deteriorating the NPs reactivity. 18 Despite these issues, such aggregation can be controlled by employing diverse organic surfactants or via the employment of various capping ligands.…”

A Method for Producing Highly Pure Magnetosomes in Large Quantity for Medical Applications Using Magnetospirillum gryphiswaldense MSR-1 Magnetotactic Bacteria Amplified in Minimal Growth Media

“…Hence, these biological nanoparticles have been considered for various medical applications, especially for tumor nanoparticle-mediated hyperthermia treatments (Alphandéry et al, 2017;Le Fèvre et al, 2017). Compared with other species, MSR-1 is the species that can reach the largest magnetosome production yield (MPY), making it the best candidate for producing magnetosomes for medical applications, as reported elsewhere by comparing the MPY obtained from the different MTB species, i.e., MSR-1, AMB-1, MS-1, MV-1 (Ali et al, 2017). However, a few hurdles Abbreviations: CaCl 2 , Calcium chloride; D, diameter of magnetosomes in bacterium; IONP, iron oxide nanoparticles; FeCl 3 ·6H 2 O, Iron chloride hexa-hydrate; K 2 HPO 4 , Potassium phosphate dibasic; L-LA, L-Lactic acid; MC, Magnetosome chains; ME, mineral elixir; MgSO 4 ·7H 2 O, Magnesium sulfate hepta-hydrate; MR, magnetic response; MSR-1, Magnetospirillum Gryphiswaldense; MTB, magnetotactic bacteria; n, number of magnetosomes per bacterium; NH 3 , Ammonia; NH + 4 , Ammonium; NH 4 Cl, Ammonium chloride; OD 565 , optical density measured at 565 nm; TEM, transmission electron microscopy; YE, yeast extract; dO 2, dissolved oxygen concentration.…”