Microbial Activation of Bacillus subtilis-Immobilized Microgel Particles for Enhanced Oil Recovery

Abstract

Microbially enhanced oil recovery involves the use of microorganisms to extract oil remaining in reservoirs. Here, we report fabrication of microgel particles with immobilized Bacillus subtilis for application to microbially enhanced oil recovery. Using B. subtilis isolated from oil-contaminated soils in Myanmar, we evaluated the ability of this microbe to reduce the interfacial tension at the oil-water interface via production of biosurfactant molecules, eventually yielding excellent emulsification across a broad range of the medium pH and ionic strength. To safely deliver B. subtilis into a permeable porous medium, in this study, these bacteria were physically immobilized in a hydrogel mesh of microgel particles. In a core flooding experiment, in which the microgel particles were injected into a column packed with silica beads, we found that these particles significantly increased oil recovery in a concentration-dependent manner. This result shows that a mesh of microgel particles encapsulating biosurfactant-producing microorganisms holds promise for recovery of oil from porous media.

Protective composite silica/polyelectrolyte shell with enhanced tolerance to harsh acid and alkali conditions

“…[38,[39][40][41] Reaction (1) occurs in water, but it is catalysed by hydroxyl ions and is completed only in sufficiently alkaline solutions. [40] Hence, with base catalysis, more and more silica hydrolysizes into Si-OH, Si(OH) 2 , Si(OH) 3 and Si(OH) 4 . Such hydroated silica will quickly react with hydroxyl ions, as exemplified in reaction (2) and (3), which may promote the connection and merge between individual silica NPs and result a swelling to some degree.…”

“…[40] Hence, with base catalysis, more and more silica hydrolysizes into Si-OH, Si(OH) 2 , Si(OH) 3 and Si(OH) 4 . Such hydroated silica will quickly react with hydroxyl ions, as exemplified in reaction (2) and (3), which may promote the connection and merge between individual silica NPs and result a swelling to some degree. [39,41] The deprotonation of hydroated silica and the consequent formation of dissolvable Si-Oand Na 2 H 2 SiO 4 facilitates the detachment of silica into the solution.…”

“…[1,2] For oil/gas recovery applications, improving the stability of surfactants under high salinity or high temperature environments is of great importance to achieving high-yield oil/gas but still presenting as a huge challenge. [3] For biological and biomedical applications, chemical stability of pharmaceutical molecules, as well as live bacterial cells for therapeutic purposes such as probiotics, is a matter of great concern as it affects the safety, efficacy and therapeutic effects of the drug products. [4][5][6] Delivering the active ingredients via protective carriers and releasing them at desired locations can significantly reduce the side effects on normal tissues and increase their therapeutic effects.…”

The influence of an applied magnetic field on the self-assembly of magnetic nanogels

“…The large variety of properties that micro-and nanogels may exhibit proves them to have a great potential for many technological and biomedical applications [13,[16][17][18][19]. They serve to create responsive coatings [20,21], chemical sensors and biosensing probes [22][23][24][25], as well as in tissue engineering [26], manipulation and template-based synthesis of solid nanoparticles [27,28] or water management and oil or pollutant recovery Email address: ivan.novikau@univie.ac.at (Ivan S. Novikau * ) [29][30][31]. Nanogels have a particular relevance for drug delivery systems, as their structural changes can control the confinement and release of cargos whereas their reduced size allows them to cross biological barriers that are insurmountable obstacles for larger particles [26,[32][33][34][35][36][37].…”

Studying synthesis confinement effects on the internal structure of nanogels in computer simulations

“…Nowadays, it is possible to create colloidal gel particles responsive to a large variety of stimuli, including temperature, pH of the solvent or external fields [4][5][6][7][8][9][10][11][12][13][14][15][16]. Prospective applications are as diverse as targeted drug delivery, oil spill recovery or sensing and smart coating technologies [10,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Even the term 'microgel' is still applied often to gel particles of any size up to roughly 100 µm, a conventional distinction between nanogelsreferred to particles with sizes from 1 to 100 nm-and microgels-naming only particles from 0.1 to 100 µm-is becoming widespread [33].…”