Lupton, N., Connell, L.D., Heryanto, D., Sander, R., Camilleri, M., Down, D.I., Pan, Z., 2020. Enhancing biogenic methane generation in coalbed methane reservoirs - Core flooding experiments on coals at in-situ conditions. International Journal of Coal Geology 219, 103377.

http://www.sciencedirect.com/science/article/pii/S0166516219307943 Stimulation of microbial methanogenesis on intact coal under in-situ conditions is demonstrated in a series of 18 anaerobic core flooding experiments. The experiments used core samples from producing coalbed methane fields in the Surat Basin and Bowen Basin, with formation water containing methanogenic microbial consortia sourced from within the matching basin. The formation water was amended with nutrients containing phosphorus and nitrogen before being used in core flooding experiments of between 6 and 20 weeks duration. Since the core floods used degassed coal core at reservoir pressure, gas generated during the core flood could be adsorbed and retained by the coal. Therefore the quantity of methane generated was determined at the end of the experiment by decreasing the pore pressure and measurement of the volume of gas desorbed from the core sample. The amount of methane generated, averaged on a per week basis, varied considerably across the different core floods but was up to 7.75 μmol methane per gram o f coal per week, comparable to previous studies where biostimulation experiments were conducted on crushed coal particles. During the core floods, the nutrient concentration was measured periodically in inflow and outflow water samples and the rates of nutrient consumption determined. The concentration of methane dissolved in the water samples was also determined and used as an indicator during a core flood of the relative rate of methanogenesis. Plateaus in gas generation were observed in the majority of core floods despite constant nutrient supply, indicating nutrient availability is not the single limiting factor to sustained methanogenesis. Higher gas generating core floods displayed higher rates of utilisation of phosphorus, underlining its importance in stimulation of microbial activity, while nutrient utilisation and gas generation measured in the absence of continuous nutrient delivery suggests the possibility of injection and production from a single CBM well. Results demonstrate the ability to stimulate gas generation on intact coal under reservoir conditions, an important step in development of technology for increasing gas content in depleted or undersaturated CBM fields.

Ma, X., Meng, L., Zhang, H., Zhou, L., Yue, J., Zhu, H., Yao, R., 2020. Sophorolipid biosynthesis and production from diverse hydrophilic and hydrophobic carbon substrates. Applied Microbiology and Biotechnology 104, 77- 100.

https://doi.org/10.1007/s00253-019-10247-w Sophorolipids (SLs), mainly synthesized by yeasts, were a sort of biosurfactant with the highest fermentation level at present. In recent years, SLs have drawn extensive attention for their excellent physiochemical properties and physiological activities. Besides, issues such as economics, sustainability, and use of renewable resources also stimulate the shift from chemical surfactants towards green or microbial-derived biosurfactants. SLs' large -scale production and application were restricted by the relatively high production costs. Currently, waste streams from agriculture, food and oil refining industries, etc., have been exploited as low-cost renewable substrates for SL production. Advanced cultivation method, uncommonly used substrates, and new genetically modified SL-producing mutants were also designed and applied to improve the productivity or the special properties of SLs. In this review, a systematic and detailed description of primary and secondary metabolism pathways involved in SL biosynthesis was summarized firstly. Furthermore, based on the pathways of SL biosynthesis from different carbon substrates, we reviewed the current knowledge and advances in the exploration of cost-effective and infrequently used hydrophilic and hydrophobic substrates for large or specialized SL production.

Ma, Y., Zhang, Y., Zhang, R., Guan, F., Hou, B., Duan, J., 2020. Microbiologically influenced corrosion of marine steels within the interaction between steel and biofilms: a brief view. Applied Microbiology and Biotechnology 104, 515-525.

https://doi.org/10.1007/s00253-019-10184-8