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High-moisture extrusion (HME) is an appealing strategy for the production of textured vegetable proteins (TVP) with meat-like structures. However, the processing parameters and formulation have a limited influence on the quality characteristics of the final HME-TVP. Therefore, we improved the component design of the cooling die, which is critical to protein texturisation, to yield the desired extruded products. In the present study, a multihole nozzle set was specifically designed to regulate protein texturisation in the cooling die. The fibrous structure, texture, and in vitro digestibility of the nozzle-produced HME-TVP were investigated at different cooling temperatures. The results showed that the integration of a multihole nozzle in the cooling die greatly improved protein texturisation. In contrast to the parabolic fiber distribution of conventionally extruded proteins, the resulting HME-TVP featured a meat-like structure with parallel and straight fibers. Furthermore, nozzle-produced HME-TVP at 40 °C exhibited excellent freeze-thaw stability and rehydration capacity. Significant structural changes in HME-TVP had little impact on protein digestibility unless the cooling die temperature was below 40 °C. These findings provide a valuable technical path to improve the quality of plant-based meat analogue products. [Display omitted] • The multihole nozzle sheet considerably promoted protein texturisation. • Nozzle-formed protein extrudates exhibited a fiber-rich, meat-like structure. • The cooling nozzle set yielded extrudates with improved processing characteristics. [ABSTRACT FROM AUTHOR]

Paddy methane (CH 4 ) production is biologically dominated by methanogenic archaea that metabolize a variety of organic and/or inorganic carbon sources. Though formate is easily dissimilated into H 2 /CO 2 , formate-metabolizing methanogenic archaea are distinct from CO 2 -utilizing methanogen taxa. The identity of formate-metabolizing methanogenic archaea in paddy soil remains elusive. In this investigation, molecular approaches based on stable isotope probing (SIP) technique were conducted to identify the formate-metabolizing methanogenic archaea in paddy soil. CH 4 emission monitor, real-time quantitative PCR (qPCR) and Denaturing Gradient Gel Electrophoresis (DGGE) analyses consistently indicated that some methanogenic archaea metabolized 13 C-labeled formate in microcosm and accounted for a large portion of formate-metabolizing archaea in anoxic paddy soil. Phylogenetic identification further found that this guild was affiliated to Methanobacteriaceae . Taken together Methanobacteriaceae could be the dominant formate-metabolizing methanogenic archaea and play an important role in the CH 4 production in paddy soil. These findings would extend the extant knowledge on paddy methanogenic archaea and microbial-driven paddy CH 4 emission. [ABSTRACT FROM AUTHOR]

Organic C has many benefits for soil, but it is depleted by tillage and crop harvest, and especially so for biofuel crops. Accordingly, strategies such as partially retaining stover or planting a cover crop can help ameliorate the negative effect of C removal. We used a long-term field experiment to study the impacts of stover retention and planting a cover crop on soil organic matter (SOM), its extractable components, and the soil microbial community. SOM chemical composition characterization was determined by electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in sequential water, methanol (MeOH), and chloroform (CHCl 3) extracts. The characteristics of the soil bacterial community were measured by phospholipid fatty acid (PLFA), real-time quantitative PCR, and 16S rRNA gene sequence. The variations in total SOM content, total microbial biomass, and bacterial population were slight among treatments, but SOM chemical compounds, arbuscular mycorrhizal fungi (AMF) biomass, and bacterial structure changed significantly, and especially so in the coupled application of stover retention and cover crop. Specifically, stover retention enriched more lignin-like compounds in soil, whereas cover crop enriched more condensed hydrocarbons, and had more compounds with an aromaticity index (AI) > 0.5. The bacterial community was not altered by the cover crop, but the corn stover retention increased the relative abundances of Myxococcales (Deltaproteobacteria) and decreased that of Actinobacteria. Redundancy analysis (RDA) further revealed that the bacterial community in the stover treatments had a significant positive association with CHCl 3 -extracted chemical classes, i.e. unsaturated hydrocarbons and lipids, with the coupled application (stover and cover crop), and lignin and proteins with the corn stover only treatment. Taken together, our study shows how different C addition practices influence the molecular composition of SOM and the structure of soil microbial communities. • Soil carbon was characterized by ion cyclotron resonance mass spectrometry. • Corn stover and rye cover crop changed composition of extractable soil organic C. • Corn stover retention enhanced lignin-like compounds. • Cover crop enriched more condensed hydrocarbons. • Soil bacterial community composition corresponded to certain SOM compositions. [ABSTRACT FROM AUTHOR]

Nitrite-driven anaerobic oxidation of methane (nitrite-driven AOM), mediated by ' Candidatus Methylomirabilis oxyfera' (M. oxyfera)-related bacteria, is a newly-discovered CH 4 consumption process in coastal wetlands. Although Spartina alterniflora invasion significantly affects CH 4 emissions from coastal wetlands, its impact on the nitrite-driven AOM process and the underlying mechanisms remain unknown. Here, we examined nitrite-driven AOM activity and M. oxyfera -related bacterial community in four coastal wetlands along the southeastern coast of China, under invasive Spartina alterniflora and native plants, including Kandelia candel , Avicennia marina or Phragmites australis. Linear mixed-effects models indicated that the Spartina alterniflora invasion stimulated the overall nitrite-driven AOM activity by an average of 61.5% in coastal wetlands (p < 0.05), but had no impact on the M. oxyfera -related bacterial abundance (p > 0.05). The nitrite-driven AOM activity was 7.1 times higher under Spartina alterniflora than under native species in Yueqing Bay (p < 0.05), and was 34.7%, 8.9% and 15.1% higher under Spartina alterniflora than under native species in Hengsha Island, Jiulong River and Zhanjiang, respectively (p > 0.05). Spartina alterniflora invasion increased the bacterial abundance in Yueqing Bay and Jiulong River Estuary by 6.8 and 7.6 times, respectively, while decreased the abundance by 34.4% and 51.4%, respectively, in Hengsha Island and Zhanjiang (p > 0.05). The partial least squares path model indicated an indirect impact of Spartina alterniflora invasion on the nitrite-driven AOM activity through its effect on soil properties, primarily including dissolved organic carbon content and nitrate content. The Spartina alterniflora invasion did not greatly alter M. oxyfera -related bacterial community. Overall, we shed new light on the potential impact of Spartina alterniflora invasion on CH 4 cycling in coastal wetlands. [Display omitted] [ABSTRACT FROM AUTHOR]

Organic vegetable cultivation under plastic greenhouse conditions is expanding rapidly in the suburb of big cities in China due to the increasing demand for organic, out-of-season green vegetables and the sustainable development of agriculture. Phosphorus (P) is not only an important plant nutrient, but also a major contaminant in the water environment. However, information on the accumulation and distribution of P in organic vegetable soils under plastic greenhouse conditions is limited, relative to the open cultivation systems. Therefore, twenty-six plastic greenhouse vegetable soils (PGVS) were selected randomly from four representative organic vegetable cultivation sites located in the suburb of Nanjing, China. For comparison, 15 open vegetable soils (OVS) near the PGVS with similar soil and cultivation practices were selected. Soil pH, organic matter (OM) and the various P accumulation characteristics were investigated. We found that soil pH in PGVS were significantly decreased by 0.57–1.17 unit with obvious signs of acidification, compared with that in OVS. Soil OM was different for different sampling locations, but in general it was higher in PGVS than OVS. Soil total P (TP), inorganic P (P i ) and Olsen-P of PGVS were higher than those in the OVS. Olsen-P of all soil samples were far above the recommended optimum value of 20 mg kg −1 for field crops, and over 60% soil samples were considered excessive (>150 mg kg −1 ) in the PGVS and OVS. There were significant correlations between total P, available P and soil pH in those vegetable soils. Al-P/Fe-P ratio was also significantly correlated with vegetable soil pH (Y pH = 7.44–1.32 X Al-P/Fe-P , r = − 0.705, p < 0.01). Soil total P i was negatively correlated with soil pH in vegetable soils ( r = −0.328, p < 0.05), but the interactive effect of soil various P i and soil pH need to be further investigated through a series of controlled tests. Our results suggest that the rapid P accumulation and acidification make the current plastic greenhouse vegetable production in the study area unsustainable and better organic manure management practices need to be implemented to sustain crop yields while minimizing the impact of vegetable production on the environment. [ABSTRACT FROM AUTHOR]