Abstract Microbial fermentation can be responsible for flavor production and increasing the nutritional quality of fermented fish foods. The study aimed to isolate non-halophilic bacteria possessing proteolysis and lipolysis properties as starter cultures for low-salt content fermentation of coarse fish. The strains with high enzyme activities were screened and multiple growth characteristics were analyzed. The content of amino acid nitrogen and trichloroacetic acid (TCA)-soluble peptides in fermented fish was also investigated under different fermentation conditions. Nuclear magnetic resonance (NMR) metabolomics analysis was utilized to monitor the metabolite profile of fermented fish paste. The isolate was identified as Bacillus velezensis DZ11. The strain DZ11 exhibited obvious hydrolysis properties of lipids and proteins. During the fermentation of fish paste, a total of 40 differential metabolites were identified, of which multiple metabolites changed significantly, including nutrient-related substances and flavor precursors. Salt concentration and strain DZ11 had important effects on the differential metabolites. B. velezensis DZ11 under longer fermentation time promoted the formation of flavor precursors and potentially increased the nutritional substances of low-salt fermented fish.

Abstract Background Field bindweed (Convolvulus arvensis L.) is a hardy perennial weed currently threatening many agroecosystems and orchard ecosystems in China. It can be spread farther by seed with a long dormancy. Objective This study aimed to evaluate the seasonal changes in germinability, dormancy and viability of field bindweed seeds in the unique arid environment in northwest China. Methods Seeds were subject to burial at various depths in the field, outdoor and indoor storage, or dry- and wet-cold stratification (5 C) treatments for 12 months. Seed germinability was tested at monthly intervals. Results No seed at 0- or 1-cm burial depths germinated in situ. Seeds buried at 3-20 cm started to germinate after 4 months, with steady increase in germination in situ over the next 7-month burial period. Some ungerminated seeds under field conditions released dormancy and could germinate ex situ under optimal laboratory conditions. The rapid dormancy release occurred under outdoor storage conditions and 13%–30% seed germinated ex situ. However, seeds from the indoor storage maintained a high level of dormancy with germination less than 12%. The dry/cold stratification was more effective in breaking seed dormancy than the wet/cold treatment. Most of the seeds (> 87%) retained their viability during the 12-month period. Conclusions Low temperature could partially break seed dormancy of field bindweed. The optimal emergence depth was 3–5 cm and the best time to control this weed species was from April to October. In view of the high seed viability, late season weed control is necessary to stop seedset.

This study investigated the removal of 17a-ethynylestradiol (EE2) from water using activated carbon adsorption and powdered activated carbon/ultrafiltration (PAC/UF). EE2 was easily adsorbed by PAC. The adsorption of EE2 fitted the Freundlich model well. The influences of initial EE2 concentration, filtration rate, PAC dose, natural organic matter (NOM), and sodium dodecyl benzene sulfonate (SDBS) were investigated. The EE2 concentration and filtration rate had no significant effect on EE2 removal, whereas the addition of PAC had a significant effect on EE2 removal. The removal rate of EE2 increased dramatically from 7.01% to 80.03% as the PAC dose was increased from 0 to 10 mg/L. Both SDBS and NOM decreased the EE2 removal efficiency. The removal efficiency of EE2 in the PAC/UF process decreased from 86.77% to 42.64% as the SDBS concentration was increased from 0 to 50 mg/L. It was concluded that activated carbon adsorption and PAC/UF can be used for the effective removal of EE2 from water.

Land application of intensive swine farm wastewater has raised serious environmental concerns due to the accumulation and microbially mediated transformation of large amounts of swine wastewater organic C (SWOC). Therefore, the study of SWOC mineralization and dynamics of wastewater microorganisms is essential to understand the environmental impacts of swine wastewater application. We measured the C mineralization of incubated swine wastewaters with high (wastewater H) and low (wastewater L) organic C concentrations. The dynamics of bacteria metabolic profile and community structure were also investigated. The results showed that SWOC mineralization was properly fitted by the two-simultaneous reactions model. The initial potential rate of labile C mineralization of wastewater H was 46% higher than that of wastewater L, whereas the initial potential rates of recalcitrant C mineralization of wastewaters H and L were both around 23 mg L-1 d-1. The bacterial functional and structural diversities significantly decreased for both the wastewaters during SWOC mineralization, and were all negatively correlated to specific UV absorbance (SUVA254; P < 0.01). The bacteria in the raw wastewaters exhibited functional similarity, and both metabolic profile and community structure changed with the mineralization of SWOC, mainly under the influence of SUVA254 (P < 0.001). These results suggested that SWOC mineralization was characterized by rapid mineralization of labile C and subsequent slow decomposition of recalcitrant C pool, and the quality of SWOC varied between the wastewaters with different amounts of organic C. The decreased bio-availability of dissolved organic matter affected the dynamics of wastewater bacteria during SWOC mineralization.