Biology subjects

Sorokin, D. Y.

Publications and source records attributed to Sorokin, D. Y..

3 recordsLinked to original sources

bioRxiv2026

Dark CO2 Fixation via the Ethylmalonyl-CoA Pathway Establishes Metabolic Parity: A Stoichiometric Basis for Compounding Ecosystem Shifts

A central challenge in microbial ecology is understanding how competing guilds coexist and why community structures unexpectedly drift away from theoretical steady states. While polyphosphate accumulation provides energy and redox buffering in many heterotrophs, how competing lineages occupying the same ecological niche without polyphosphate synthesis manage equivalent intracellular redox imbalances remains unposed. Using an enhanced biological phosphorus removal macrocosm, we integrated quantitative stoichiometry with metaproteomics to resolve alternative metabolic strategies that underpin cellular homeostasis in heterotrophs. We show that glycogen-accumulating organisms (GAOs) achieve baseline metabolic parity with polyphosphate-accumulating organisms (PAOs) through a parallel redox-buffering mechanism: heterotrophic CO2/HCO3- re-assimilation via the ethylmalonyl-CoA pathway. This inorganic carbon fixation couples structural carbon conservation with tight redox control, mitigating intracellular electron overflow and eliminating the long-assumed GAO bioenergetic inferiority. The bioenergetic efficiency of GAOs is further fortified by fine-tuned metabolic wiring, featuring energy-efficient high affinity acetate activation, ferredoxin-centered biochemistry, and energy-neutral polyhydroxyalkanoates (PHA) mobilization. Strikingly, minor formate co-feeding disrupted this established PAO/GAO parity. Stoichiometric simulations revealed that this formate supplementation creates an asymmetric bioenergetic niche that grants per-cycle energy gains exclusively to GAOs. Decoupled from hydraulic throughput, solids retention time control retains cells carrying accumulated intracellular inventory, translating subtle per-cycle stoichiometric edges into a multi-generational ratchet and drives a rapid community shift from PAO/GAO co-dominance to GAO dominance. By exposing limitations of traditional single-substrate and single-cycle steady-state models, our findings reveal how inorganic resource management and generational metabolic compounding govern community assembly in biomass-retaining microbial ecosystems.

bioengineering↗

bioRxiv2026

Physiology, functional genomics and proteomics of Verruconatronum alginivorum gen. nov., sp. nov., a first haloalkaliphilic representative of the phylum Verrucomicrobiota from soda habitats

Despite the successful cultivation of many microbes from rich bacterial communities inhabiting alkaline soda lakes, members of the bacterial phylum Verrucomicrobiota have so far been detected only through metagenomics. Here, we used alginate as a selective substrate to enrich and isolate two strains of haloalkaliphilic Verrucomicrobiota. The isolates share identical 16S rRNA gene sequences representing a new genus lineage, and, together with other metagenome assembled genomes, a new family within Opitutales. Cells of strains AB-alg1T (from soda lakes) and AB-alg4 (from soda solonchak soils) are small and motile cocci forming submerged colonies in soft alginate agar. They are saccharolytic heterotrophs growing aerobically on polysaccharides (alginate, starch and inulin) and sugars (glucose, fructose, mannose, sucrose, melezitose, maltose and cellobiose). They also grow anaerobically by fermentation of alginate and D-mannose and by coupling incomplete denitrification to oxidation of alginate. Both isolates are obligately alkaliphilic and moderately salt-tolerant. The dominant membrane phospholipids include phosphatidylcholines and diphosphatidylglycerols (cardiolipins). The genome of AB-alg1T features polysaccharide lyases of the PL6, 7, 15, 17, 38, and 39 families for depolymerization of alginate. Based on distinct phenotype and phylogeny, we propose classification of strains AB-alg1T (JCM 35393T=UQM 41574T) and AB-alg4 as Verruconatronum alginivorum gen. nov., sp. nov. within a new family Verruconatronumaceae. ImportanceThe presented isolates are the first isolated representatives of an environmental family of Opitutales, part of the core microbiome of alkaline soda lakes. These bacteria feed on polysaccharides. We present the key enzymatic machinery for the polysaccharide breakdown. These enzymes are high-pH tolerant and have potential for industry applications, for example in washing powders and biomass waste recycling.

microbiology↗

bioRxiv2019

Differential polysaccharide utilization is the basis for a nanohaloarchaeon : haloarchaeon symbiosis.

Nanohaloarchaeota, a clade of diminutive archaea, with small genomes and limited metabolic capabilities, are ubiquitous in hypersaline habitats, which they share with the extremely halophilic and phylogenetically distant euryarchaea. Some of these nanohaloarchaeota and euryarchaea appear to interact with each other. In this study, we investigate the genetic and physiological nature of their relationship. We isolated the nanohaloarchaeon Candidatus Nanohalobium constans LC1Nh and the haloarchaeon Halomicrobium sp. LC1Hm from a solar saltern, reproducibly co-cultivated these species, sequenced their genomes, and characterized their metabolic/trophic interactions. The nanohaloarchaeon is a magnesium-dependent aerotolerant heterotrophic anaerobe of the DPANN superphylum; it lacks respiratory complexes and its energy production relies on fermentative metabolism of sugar derivatives, obtained by depolymerizing alpha-glucans or by acquiring the chitin monomer N-acetylglucosamine from the chitinolytic haloarchaeal host. Halomicrobium is a member of the class Halobacteria and a chitinotrophic aerobe. The nanohaloarchaeon lacks key biosynthetic pathways and is likely to be provided with amino acids, lipids, nucleotides and cofactors via physical contact with its host Halomicrobium. In turn, the ability of Ca. Nanohalobium to hydrolyse alpha-glucans boosts the hosts growth in the absence of a chitin substrate. These findings suggest that at least some members of the nanohaloarchaea, previously considered ecologically unimportant given their limited metabolic potential, in fact may play significant roles in the microbial carbon turnover, food chains, and ecosystem function. The behaviour of Halomicrobium, which accommodates the colonization by Ca. Nanohalobium, can be interpreted as a bet-hedging strategy, maximizing its long-term fitness in a habitat where the availability of carbon substrates can vary both spatially and temporarily.

microbiology↗