Reference genomes of the two cultivated jute species.

Cultivated jute, which comprises the two species Corchorus capsularis and C. olitorius, is the second most important natural fibre source after cotton. Here we describe chromosome-level assemblies of the genomes of both cultivated species. The C. capsularis and C. olitorius assemblies are each comprised of seven pseudo-chromosomes, with the C. capsularis assembly consisting of 336 Mb with 25,874 genes and the C. olitorius assembly containing 361 Mb with 28 479 genes. Although the two Corchorus genomes exhibit collinearity, the genome of C. olitorius contains 25 Mb of additional sequences than that of C. capsularis with 13 putative inversions, which might give a hint to the difference of phenotypic variants between the two cultivated jute species. Analysis of gene expression in isolated fibre tissues reveals candidate genes involved in fibre development. Our analysis of the population structures of 242 cultivars from C. capsularis and 57 cultivars from C. olitorius by whole-genome resequencing resulted in post-domestication bottlenecks occurred ~2000 years ago in these species. We identified hundreds of putative significant marker-trait associations (MTAs) controlling fibre fineness, cellulose content and lignin content of fibre by integrating data from genome-wide association studies (GWAS) with data from analyses of selective sweeps due to natural and artificial selection in these two jute species. Among them, we further validated that CcCOBRA1 and CcC4H1 regulate fibre quality in transgenic plants via improving the biosynthesis of the secondary cell wall. Our results yielded important new resources for functional genomics research and genetic improvement in jute and allied fibre crops.

Closing CO2 Loop in Biogas Production: Recycling Ammonia As Fertilizer.

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions. The ammonia removal efficiency in vacuum membrane distillation is around 75% regardless of the ammonia concentration of the biogas slurry. The recovered ammonia is used for CO2 absorption to realize simultaneous biogas upgrading and fertilizer generation. CO2 absorption performance of the recovered ammonia (absorption capacity and rate) is compared with a conventional model absorbent. Theoretical results on biogas upgrading are also provided. After ammonia recovery, the treated biogas slurry has significantly reduced phytotoxicity, improving the applicability for agricultural irrigation. The novel concept demonstrated in this study shows great potential in closing the CO2 loop in biogas production by recycling ammonia as an absorbent for CO2 absorption associated with producing fertilizers.

Enhancing the Ammonia Selectivity by Using Nanofiber PVDF Composite Membranes Fabricated with Functionalized Carbon Nanotubes.

Conventional hydrophobic membrane-based membrane distillation (MD) has been applied for ammonia recovery from an anaerobic digestion (AD) effluent. However, the typical hydrophobic membranes do not have selectivity for ammonia and water vapor, which results in high energy consumption from the water evaporation. To enhance the selectivity during the ammonia recovery process, the functionalized carbon nanotubes (CNTs)/polyvinylidene fluoride (PVDF) nanofiber membranes were fabricated by electrospinning, and the effects of different CNTs and their contents on the performance of nanofiber membranes were investigated. The results indicate that CNTs can be successfully incorporated into nanofibers by electrospinning. The contact angles of the composite membrane are all higher than those of commercial membrane, and the highest value 138° can be obtained. Most importantly, under the condition of no pH adjustment, the ammonia nitrogen transfer coefficient reaches the maximum value of 3.41 × 10-6 m/s, which is about twice higher than that of commercial membranes. The ammonia separation factor of the carboxylated CNT (C-CNT) composite membrane is higher than that of the hydroxylated CNT(H-CNT) composite membrane. Compared with the application of the novel C-CNT composite membrane, the ammonia separation factor is 47% and 25% higher than that of commercial and neat PVDF membranes. This work gives a novel approach for enhancing ammonia and water selectivity during AD effluent treatment.

Simultaneous biogas upgrading, CO2 sequestration, and biogas slurry decrement using biomass ash.

A novel system for simultaneous biogas upgrading, CO2 sequestration, and biogas slurry decrement was established by adding biomass ash into biogas slurry to form a renewable CO2 mixture absorbent. After CO2 saturation, the CO2-rich mixture absorbent could be applied for plant growth. When the mass ratio of liquid to solid was 4:1, CO2 absorption capacity of this mixture absorbent reached up to 97.33 g-CO2/kg-biomass-ash, which was about 135% higher than that of the biomass ash-water mixture. The highest value of 129.94 g-CO2/kg-biomass-ash was obtained at a liquid-solid ratio of 99:1. When the TS concentration of anaerobic digestion feedstock was higher than 16 wt% and the water content of CO2-rich absorbent was about 50 wt%, more than 80% of biogas slurry can be adsorbed by the biomass ash. If the biomass ash with a CO2 absorption capacity of 100 g-CO2/kg was adopted and its transportation distance was less than 45 km, the biogas upgrading cost could be lower than the global average level (about RMB¥ 0.7/Nm3-biogas) when using the novel system proposed in this study.

A new approach for biogas slurry disposal by adopting CO2-rich biogas slurry as the flower fertilizer of Spathiphyllum: Feasibility, cost and environmental pollution potential.

A new approach for biogas slurry disposal was put forward in this study through converting biogas slurry to the organic fertilizer of Spathiphyllum. The biogas slurry was firstly concentrated by vacuum distillation to reduce its volume by 80% who is called 5CBS, and then CO2 saturated to reduce its pH to about 6.50 ± 0.20. With or without adding the exogenetic Ca, Mg and P nutrients, CO2-rich 5CBS (i.e., CR-5CBS) was adopted as the root or foliar fertilizer to cultivate Spathiphyllum. Additionally, the commercial Spathiphyllum fertilizer was also experimented as a control. Results showed that the cases adopting CR-5CBS as the root or foliar fertilizer can obtain the agronomic traits and ornamental values of Spathiphyllum better those irrigated by the commercial fertilizer. Exogenetic nutrients added into CR-5CBS can lead to a decreased dead leaf number of Spathiphyllum, an enhanced N assimilation performance, however only a slightly improved assimilation performance of Ca, Mg and P. In terms of the fertilizer economy, CR-5CBS without exogenetic nutrient addition may be a promising for replacing the commercial Spathiphyllum fertilizer in the future. Economic and environmental pollution potential (EPP) analyses indicated that treating biogas slurry as the organic flower fertilizer can achieve a high net profit with about $ 28.89/m3-biogas slurry and a negative EPP value (-3.9), showing its profitability and environmental friendliness.