The recent discovery of completely nitrifying Nitrospira demands a re-examination of nitrifying environments to evaluate their contribution to nitrogen cycling. To approach this challenge, tools are needed to detect and quantify comammox Nitrospira. We present primers for the simultaneous quantification and diversity assessement of both comammox Nitrospira clades. The primers cover a wide range of comammox diversity, spanning all available high quality sequences. We applied these primers to 12 groundwater-fed rapid sand filters, and found comammox Nitrospira to be abundant in all filters. Clade B comammox comprise the majority (∼75%) of comammox abundance in all filters. Nitrosomonadaceae were present in all filters, although at low abundance (mean = 1.8%). Ordination suggests that temperature impacts the structure of nitrifying communities, and in particular that increasing temperature favours Nitrospira. The nitrogen content of the filter material, sulfate concentration and surface ammonium loading rates shape the structure of the comammox guild in the filters. This work provides an assay for simultaneous detection and diversity assessment of clades A and B comammox Nitrospira, expands our current knowledge of comammox Nitrospira diversity and demonstrates a key role for comammox Nitrospira in nitrification in groundwater-fed biofilters.

The heteropolymer lignin represents an untapped resource for production of renewable aromatic chemicals, if efficient depolymerisation methods can be developed. In this work, the metabolic pathways in Rhodococcus jostii RHA1 for degradation of aromatic lignin breakdown products are re-routed, in order to generate an aromatic dicarboxylic acid product that could be used for bioplastic synthesis. Protocatechuic acid is normally metabolised via ortho-cleavage to the -keto-adipate pathway. Insertion of recombinant genes for protocatechuate 4,5-dioxygenase or protocatechuate 2,3-dioxygenase into R. jostii RHA1, followed by ammonia cyclisation of the extradiol cleavage products, generates pyridine 2,4-dicarboxylic acid or pyridine 2,5-dicarboxylic acid bioproducts in yields of 80-125 mg/L when grown on minimal media containing 1% wheat straw lignocellulose.

One-pot multienzyme continuous cascade for the conversion of HMF to FDCA using HRP to activate GOaseM3-5 in situ.

No abstract

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Genetic modification of Rhodococcus jostii RHA1 was carried out in order to optimise the production of pyridine-2,4-dicarboxylic acid and pyridine-2,5-dicarboxylic acid bioproducts from lignin or lignocellulose breakdown, via insertion of either the Sphingobium SYK-6 ligAB genes or Paenibacillus praA gene respectively. Insertion of inducible plasmid pTipQC2 expression vector containing either ligAB or praA genes into a ΔpcaHG R. jostii RHA1 gene deletion strain gave 2–threefold higher titres of PDCA production from lignocellulose (200–287 mg/L), compared to plasmid expression in wild-type R. jostii RHA1. The ligAB genes were inserted in place of the chromosomal pcaHG genes encoding protocatechuate 3,4-dioxygenase, under the control of inducible Picl or PnitA promoters, or a constitutive Ptpc5 promoter, producing 2,4-PDCA products using either wheat straw lignocellulose or commercial soda lignin as carbon source. Insertion of Amycolatopsis sp. 75iv2 dyp2 gene on a pTipQC2 expression plasmid led to enhanced titres of 2,4-PDCA products, due to enhanced rate of lignin degradation. Growth in minimal media containing wheat straw lignocellulose led to the production of 2,4-PDCA in 330 mg/L titre in 40 h, with > tenfold enhanced productivity, compared with plasmid-based expression of ligAB genes in wild-type R. jostii RHA1. Production of 2,4-PDCA was also observed using several different polymeric lignins as carbon sources, and a titre of 240 mg/L was observed using a commercially available soda lignin as feedstock.

Nanoporous networks exhibit effective stabilisation properties for nanoscale zero-valent iron (nZVI) and nZVI, with its reductive potentials and wide availability, offers degradative remediation of environmental contaminants.

 Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.