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In the usage phase, diesel engines fuelled with diesel-biodiesel blends produced lower soot, HC and CO emissions. However, the environmental effects should include the greenhouse gas (GHG) emissions. GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change (LUC). Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions. The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type, the precipitation and the oil contents and the cultivation conditions of plants. Then, the suggestions for biodiesel development in China were given. Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land. Jatropha curcas (J. curcas), Pistacia chinensis Bunge (P. chinensis), Comus wilsoniana (C. wilsoniana) and Xanthoceras sorbifolium Bunge (X. sorbifolium) were considered as the most promising feedstocks for biodiesel production. It is suggested to plant X. sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China. The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater. The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants. Lastly, only natural gas-based or biomass-based methanol can be used for biodiesel production.

Background Root-knot nematodes (RKNs) are harmful plant-parasitic nematodes that cause serious damage to plant hosts. In the long-term practice of RKN management, bacterial nematicides have attracted increasing attention as an effective biocontrol means. Here we determined the active substances against Meloidogyne incognita from a nematicidal bacterium, developed a biocontrol agent (BCA) based on optimized culture processes. The effects of the BCA on RKN control and plant growth-promotion were evaluated in tomato pot trials. Results Pseudomonas simiae strain MB751 exhibiting significant nematicidal activity against M. incognita second-stage juveniles (J2) with approximately 80% mortality (with culture supernatant, 96% volume percentage) was isolated from a vineyard. A set of purification and identification experiments was performed to determine the main nematicidal component in MB751. A cyclic dipeptide Cyclo(L-Pro-L-Leu) was identified with a lethal concentration necessary to kill 50% of the population (LC50 ) of 65.3 μg mL-1 against M. incognita J2. Following optimization trials on culture medium/fermentation conditions, such as the single factor test, Plackett-Burman test, steepest ascent, and response surface methodology experiments, the MB751 fermentation broth was then prepared as a BCA via a cold-air drying process. The BCA and was evaluated in tomato pot experiments for effectiveness in suppressing M. incognita. Significant effects on M. incognita suppression and plant-growth promotion as well as induced systemic resistance to M. incognita of tomato, were observed. Conclusion The cyclic dipeptide-producing bacterium P. simiae MB751 exhibited high nematicidal activity and performance. Further development of this BCA should be pursued for the management of M. incognita in agriculture. © 2021 Society of Chemical Industry.