Improved methods for mass production of magnetosomes and applications: a review

Abstract

Magnetotactic bacteria have the unique ability to synthesize magnetosomes (nano-sized magnetite or greigite crystals arranged in chain-like structures) in a variety of shapes and sizes. The chain alignment of magnetosomes enables magnetotactic bacteria to sense and orient themselves along geomagnetic fields. There is steadily increasing demand for magnetosomes in the areas of biotechnology, biomedicine, and environmental protection. Practical difficulties in cultivating magnetotactic bacteria and achieving consistent, high-yield magnetosome production under artificial environmental conditions have presented an obstacle to successful development of magnetosome applications in commercial areas. Here, we review information on magnetosome biosynthesis and strategies for enhancement of bacterial cell growth and magnetosome formation, and implications for improvement of magnetosome yield on a laboratory scale and mass-production (commercial or industrial) scale.

Magnetotactic Bacteria and Magnetosomes: Basic Properties and Applications

“…The process of obtaining a pure MTB culture is very complicated [99] and industrial cultivation of even the most studied species-e.g., Magnetospirillum magnetotacticum-requires the use of large-volume fermenters, reaching 30 [100] and even 50 L [101] (Figure 4). In addition, constant precise control of the dissolved iron content in the nutrient medium and its pH [102], and maintaining oxygen concentration in the gas phase <5% are required [76].…”

“…Isolating magnetosomes from MTB starts with exposure to air, followed by ultrasonic cell lysis or using of a laboratory extrusion cell disintegrator (French press) [140][141][142], stirring in a shaker, magnetic separation of magnetosomes, or separation by centrifugation with removing cellular debris and multiple rinsing with buffered solutions and deionized water [100,131,143]. An automated MTB cultivation mode with variable oxygen content can be used to control the particle size and, correspondingly, the magnetic characteristics of magnetite in order to adapt them for the desired application [144].…”

Advances in Magnetic Nanoparticles Engineering for Biomedical Applications—A Review

“…This disadvantage circumvents microfluidic synthesis, an approach that by minimizing the synthesis equipment to a small chip size, achieves higher and more rapid control of reaction parameters such as mixing ratio, temperature and heat transfer, resulting in increased MNP size and shape uniformity with a narrower size distribution compared to batch synthesis [25,43]. Another unique approach is employed by nature in the biosynthesis, using magnetotactic bacteria (MTB), with outstanding uniformity of size and shape [52][53][54].…”

Why Does Not Nanotechnology Go Green? Bioprocess Simulation and Economics for Bacterial-Origin Magnetite Nanoparticles

“…Multiple studies have been dedicated to increasing BMNs throughput in bioreactors (3–70 L) MTB cultures ( Silva et al, 2013 ; Basit et al, 2020 ; Berny et al, 2020 ). The main challenges concerning the cultivation of MTB in large volumes are the microaerophilic metabolism of this group, relatively slow growth rates, and specific nutritional requirements, in addition to BMNs yields in the order of mg/L ( Ali et al, 2017 ; Basit et al, 2020 ).…”

“…Multiple studies have been dedicated to increasing BMNs throughput in bioreactors (3–70 L) MTB cultures ( Silva et al, 2013 ; Basit et al, 2020 ; Berny et al, 2020 ). The main challenges concerning the cultivation of MTB in large volumes are the microaerophilic metabolism of this group, relatively slow growth rates, and specific nutritional requirements, in addition to BMNs yields in the order of mg/L ( Ali et al, 2017 ; Basit et al, 2020 ). Strategies like optimizing oxygen supply and balanced nutrient injection, have been attempted to address such hurdles and led to improved production yields ( Liu et al, 2010 ; Zhang et al, 2011 ; Fernández-Castané et al, 2018 ).…”