Development of the yeast and lactic acid bacteria co-culture agent for atmospheric ammonia removing: Genomic features and on-site applications.

Odorous gas (e.g. atmospheric ammonia) in low ventilation public places, such as public toilets and waste transfer stations, causes severe health problems. Many technologies are developed to purify the atmospheric ammonia, among which the microbial agents are supposed to be a green and economical approach. In this study, we developed a yeast, Pichia sp. J1, and a lactic acid bacterium (LAB), Lactobacillus paracasei B1, co-culture agent for atmospheric ammonia removing. The on-site application results indicated the yeast and LAB mixed fermented agent had a maximum ammonia removing efficiency of 98.78%, which is significantly higher than the pure cultures (78.93% for B1 and 75.00% for J1), indicating the co-culture agent is an excellent biological product for ammonia removal. The excellent performance of the agent is closely related to the synergy behaviors between the yeast and LAB. In the co-culture agents, some of the LAB cells adhered closely to the yeast, and the growth and lactic acid producing ability of LAB were significantly promoted by yeast. Genomic analysis indicated the complementary of nutrients, i.e. carbon and nitrogen resources, signal transduction, and adhesion proteins (regulates adhesion behavior) played roles in regulating the synergy effects. Our study offers a novel biological solution of odorous gas purification.

Synthesis of nano-silica and biogenic iron (oxyhydr)oxides composites mediated by iron oxidizing bacteria to remove antimonite and antimonate from aqueous solution: Performance and mechanisms.

Removal of antimony from wastewater is essential because of its potential harm to the environment and human health. Nano-silica and biogenic iron (oxyhydr)oxides composites (BS-Fe) were prepared by iron oxidizing bacteria (IOB) mediation and the batch adsorption experiments were applied to investigate antimonite (Sb(III)) and antimonate (Sb(V)) removal behaviors. By contrast, the synthetic BS-Fe calcined at 400 â„ƒ (BS-Fe-400) exhibited a large specific surface area (157.353 m2/g). The maximum adsorption capacities of BS-Fe-400 were 102.10 and 337.31 mg/g for Sb(III) and Sb(V), respectively, and experimental data fit well to the Langmuir isotherm and Temkin models, and followed the pseudo-second order kinetic model. Additionally, increasing pH promoted Sb(III) adsorption, while inhibited the adsorption of Sb(V), indicating that electrostatic attraction made a contribution to Sb(V) adsorption. Moreover, different co-existing ions showed different effects on adsorption. Characterization techniques of FTIR and XPS indicated that the main functional groups involved in the adsorption were -OH, C-O, CO, C-C, etc. and Sb(III) and Sb(V) may bind to iron (oxyhydr)oxides via the formation of inner-sphere complexes. The present work revealed that the synthetic BS-Fe-400 by nano-silica and biogenic iron (oxyhydr)oxides held great application potential in antimony removal from wastewater.

Removal of heavy metal(loid)s from aqueous solution by biogenic FeS-kaolin composite: Behaviors and mechanisms.

In this work, a green adsorbent, biogenic FeS-kaolin composite (KL-FeS) was synthesized by sulfate-reducing bacteria (SRB) mediation, and its potential for Cd(II), Pb(II), Cu(II), Zn(II), As(III) and Sb(III) removal was evaluated. Among prepared composites, the KL-FeS synthesized at a concentration of 2 g/L kaolin performed a better removal efficiency on heavy metal(loid)s and the adsorption results followed the pseudo-second-order and Redlich-Peterson models, indicating that the adsorption was a hybrid chemical reaction-adsorption process. Additionally, the maximum adsorption capacities of Cd(II), Pb(II), Cu(II), Zn(II), As(III) and Sb(III) on KL-FeS in monocomponent system were 71.71, 133.54, 51.90, 54.41, 38.71 and 96.38 mg/g, respectively (pH = 5.0 ± 0.1, T = 25 °C). In addition, the increase of pH and ionic strength promoted the adsorption capacities of KL-FeS for metal-(loid)s. Moreover, FTIR, XPS and XRD analyses supported that surface complexation, hydrogen bonding, ion exchange, electrostatic interaction and chemical precipitation were predominately mechanisms involved in the adsorption process. Furthermore, KL-FeS displayed higher affinity for Pb(II), Sb(III) and Cu(II) in the multi-component system. This work highlighted the potential of biogenic FeS-kaolin composite for simultaneous removal of multiple heavy metal(loid)s under aerobic conditions.

Comparative Genomics Provides Insights into the Genetic Diversity and Evolution of the DPANN Superphylum.

DPANN is known as highly diverse, globally widespread, and mostly ectosymbiotic archaeal superphylum. However, this group of archaea was overlooked for a long time, and there were limited in-depth studies reported. In this investigation, 41 metagenome-assembled genomes (MAGs) belonging to the DPANN superphylum were recovered (18 MAGs had average nucleotide identity [ANI] values of <95% and a percentage of conserved proteins [POCP] of >50%, while 14 MAGs showed a POCP of <50%), which were analyzed comparatively with 515 other published DPANN genomes. Mismatches to known 16S rRNA gene primers were identified among 16S rRNA genes of DPANN archaea. Numbers of gene families lost (mostly related to energy and amino acid metabolism) were over three times greater than those gained in the evolution of DPANN archaea. Lateral gene transfer (LGT; ∼45.5% was cross-domain) had facilitated niche adaption of the DPANN archaea, ensuring a delicate equilibrium of streamlined genomes with efficient niche-adaptive strategies. For instance, LGT-derived cytochrome bd ubiquinol oxidase and arginine deiminase in the genomes of "Candidatus Micrarchaeota" could help them better adapt to aerobic acidic mine drainage habitats. In addition, most DPANN archaea acquired enzymes for biosynthesis of extracellular polymeric substances (EPS) and transketolase/transaldolase for the pentose phosphate pathway from Bacteria. IMPORTANCE The domain Archaea is a key research model for gaining insights into the origin and evolution of life, as well as the relevant biogeochemical processes. The discovery of nanosized DPANN archaea has overthrown many aspects of microbiology. However, the DPANN superphylum still contains a vast genetic novelty and diversity that need to be explored. Comprehensively comparative genomic analysis on the DPANN superphylum was performed in this study, with an attempt to illuminate its metabolic potential, ecological distribution and evolutionary history. Many interphylum differences within the DPANN superphylum were found. For example, Altiarchaeota had the biggest genome among DPANN phyla, possessing many pathways missing in other phyla, such as formaldehyde assimilation and the Wood-Ljungdahl pathway. In addition, LGT acted as an important force to provide DPANN archaeal genetic flexibility that permitted the occupation of diverse niches. This study has advanced our understanding of the diversity and genome evolution of archaea.