Microbially induced carbonate precipitation via methanogenesis pathway by a microbial consortium enriched from activated anaerobic sludge

Abstract

Aims Various applications of microbially induced carbonate precipitation (MICP) has been proposed. However, most studies use cultured pure strains to obtain MICP, ignoring advantages of microbial consortia. The aims of this study were to: (i) test the feasibility of a microbial consortium to produce MICP; (ii) identify functional micro‐organisms and their relationship; (iii) explain the MICP mechanism; (iv) propose a way of applying the MICP technique to soil media. Methods and Results Anaerobic sludge was used as the source of the microbial consortium. A laboratory anaerobic sequencing batch reactor and beaker were used to perform precipitation experiment. The microbial consortium produced MICP with an efficiency of 96·6%. XRD and SEM analysis showed that the precipitation composed of different‐size calcite crystals. According to high‐throughput 16S rRNA gene sequencing, the functional micro‐organisms included acetogenic bacteria, acetate‐oxidizing bacteria and archaea Methanosaeta and Methanobacterium beijingense. The methanogenesis acetate degradation provides dissolved inorganic carbon and increases pH for MICP. A series of reactions catalysed by many enzymes and cofactors of methanogens and acetate‐oxidizers are involved in the acetate degradation. Conclusion This work demonstrates the feasibility of using the microbial consortium to achieve MICP from an experimental and theoretical perspective. Significance and Impact of the Study A method of applying the microbial‐consortium MICP to soil media is proposed. It has the advantages of low cost, low environmental impact, treatment uniformity and less limitations from natural soils. This method could be used to improve mechanical properties, plug pores and fix harmful elements of soil media, etc.

Biodegradation of flonicamid by Ensifer adhaerens CGMCC 6315 and enzymatic characterization of the nitrile hydratases involved

“…The half-life of FLO in the presence of E. adhaerens CGMCC 6315 was only 7.4 h, significantly shorter than that in FLO degradation by A. faecalis CGMCC 17553 (15 h), E. meliloti CGMCC 7333 (60 h), and Aminobacter sp. CGMCC 1.17253 (178.8 h) [ 15 , 17 , 18 ]. Therefore, E. adhaerens CGMCC 6315 may be more advantageous for microbial restoration of FLO-contaminated environments.…”

“…Phylogenetic analysis based on the amino acid sequences of NHase α -subunits indicated that CnhA clustered in a branch with the NHase of other FLO degrading bacteria, E. meliloti CGMCC 7333 and Aminobacter sp . CGMCC 1.17253 [ 17 , 33 ], with 82.33 and 74.42% protein sequence similarity respectively. Comparing E. adhaerens CGMCC 6315 PnhA and CnhA with the enzymes from E. meliloti CGMCC 7333, the protein similarities were 51.63% and 82.33%, respectively.…”

“…When the preincubation temperature exceeded 40 °C, Aminobacter sp. CGMCC 1.17253 NHase activity also decreased dramatically, like that of CnhA [ 17 ]. PnhF from M. flocculans CGMCC 1.6731 was preincubated for 2 h at 20–60 °C and the residual activity remained at about 60% [ 16 ].…”

“…This promotion of activity by Cu 2+ ions was not found for the NHases from other FLO-degrading bacteria ( A. faecalis CGMCC 17553, Aminobacter sp. CGMCC 1.17253, E. meliloti CGMCC 7333 and V. boronicumulans CGMCC 4969) [ 15 , 17 , 18 , 28 ]. We speculate that Cu 2+ ions may promote enzyme folding, thereby forming a larger amount of NHase with the correct conformation and hence increasing the enzyme activity [ 40 ].…”

Review of Strength Improvements of Biocemented Soils

“…Engineering responses to biotreated soil are reported to be affected by many factors : (1) environmental, which includes rainwater flushing (Mortensen et al 2011;Tang et al 2020), contamination (Cheng and Shahin 2017;Yu and Jiang 2020), temperature (Ferris et al 2004;Nemati et al 2005;Sun et al 2019b), acid rain (Gowthaman et al 2021), oxygen content (Li et al 2017a;Su and Yang 2021), salinity (Mortensen et al 2011;Tang et al 2020), wetting-drying cycles (Sharma and Satyam 2021), and freezethaw cycles (Sharma et al 2021a;Sun et al 2021b); (2) treatment and testing factors, which include chemical concentrations (Al Qabany et al 2012;Zhao et al 2014), flow rate and direction of chemical media (Martinez et al 2013), calcium resource (Choi et al 2016b;Wang et al 2021b), treatment strategy (Al Qabany et al 2012;Martinez et al 2013;Cheng and Shahin 2016), urease source (e.g., indigenous or exogenous microbes) (Dhami et al 2013b;Park et al 2014;Cheng et al 2017a;Bibi et al 2018;Gomez et al 2018b;Nayanthara et al 2019;Marin et al 2021), bacterial concentration (Bosak et al 2004;Soon et al 2014), pH (Wu et al 2019a;Zehner et al 2020), and curing time for the soaking method (Zhao et al 2014;Sharma and Satyam 2021); (3) characteristics of base materials, which include particle mineralogy…”