Study On Construction Of Compartment Microenvironments By Magnetic Responsive Pickering Emulsions For Anaerobic Culture Of Microorganism

Anaerobic bacteria play a unique role in ecological cycles,agriculture,food,and medicine.However,traditional anaerobic culture of bacteria in vitro requires specific equipment under strict conditions.The small molecule oil phase and hydrophobicized Fe₃O₄nanoparticles(C6-Fe₃O₄ NPs)are used to construct W/O type temporary Pickering emulsion anaerobic compartment microenvironments for whole process of anaerobic culture of microorganism.The highly efficient anaerobic culture performance of Pickering emulsion is demonstrated,and the mechanism of anaerobic microorganism growth at the interface of magnetically responsive Pickering emulsion is revealed.In the part of construction of compartment microenvironments by Pickering emulsions,we successfully prepare C6-Fe₃O₄ NPs via the method of alkylsilane modification,with a three-phase contact angle of 110^o.The C6-Fe₃O₄ NPs can stabilize the water-in-paraffin oil Pickering emulsion,and the size distribution of the emulsion is 60-480?m,the average diameter is 257?m.When the concentration of C6-Fe₃O₄ NPs is 1.0 wt.%and the oil-water volume ratio is 5:4,the Pickering emulsion stabilized by C6-Fe₃O₄ NPs has the best effect.In addition,the compartment microenvironments of Pickering emulsion have excellent p H stability,anaerobic performance and good reproducibility.The emulsion is expected to be widely used in the fields of biomedicine,daily chemicals and biological material cultivation.Based on the biocompatible temporary Pickering emulsion anaerobic compartment microenvironments constructed by C6-Fe₃O₄ NPs and paraffin oil,the encapsulation and whole process of anaerobic culture microorganisms are realized.Compared with conventional culture of Lactobacillus in shaking flask,the magnetically responsive Pickering emulsion of compartment microenvironments have significantly higher growth rate whether in a small-scale system(20 m L)or in a scale-up system(1 L),and still has higher cultivation ability compare with surfactant emulsion.The high growth efficiency is attributed to the fact that the Pickering emulsion of compartment microenvironments suspended in the system avoid the macroscopic precipitation of Lactobacillus,and the positively charged C6-Fe₃O₄ NPs anchored at the interface of the Pickering emulsion stick with negatively charged bacteria by the charge interaction avoid the precipitation of bacteria in the dropets.Therefore,the 3D growth of bacteria is realized(both in the dropets and in the vessel).This way increases the diffusion of bacteria and the transportation of nutrients,and reduces the inhibitory effect of the product.After the cultivation is completed,non-invasive demulsification can be achieved through magnetic response behavior,bacteria are separated,and C6-Fe₃O₄ NPs and oil phase can be reused.The C6-Fe₃O₄ NPs can be reuse 10 cycles and keep the above 81%of recovery rate,the relative bacterial concentration ratio of Lactobacillus is 78%.This study not only opens up new possibilities for the research on the growth of various microorganisms on the nano/nano scale,but also provides an efficient,convenient and low-cost platform for the exploration of microorganism world.