Turning food waste to microbial lipid towards a superb economic and environmental sustainability: An innovative integrated biological route.

With the drastic growth of the economic and population, the global energy requirement is on the rise, and massive human and material resources have been put into the development of alternative and renewable energy sources. Biodiesel has been recognized as a green and sustainable alternative energy, but the raw materials-associated source and cost makes it difficult to achieve large-scale commercial production. Microbial lipids (ML) produced by oleaginous microbes have attracted more and more topics as feedstocks for biodiesel production because of their unique advantages (fast growth cycle, small footprint and so on). However, there are still many problems and challenges ahead towards commercialization of ML-based biodiesel, especially the cost of feedstock for ML production. Food waste (FW) rich in organic matters and nutrients is an excellent and almost zero-cost feedstock for ML production. However, current biological routes of FW-based ML production have some defects, which make it impossible to achieve full industrialization at present. Therefore, this review intends to provide a critical and comprehensive analysis of current biological routes of FW-based ML production with the focus on the challenges and solutions forward. The biological routes towards future FW-based ML production must be able to concurrently achieve economic feasibility and environmental sustainability. On this condition, an innovative integrated biological route for FW-based ML production has thus been put forward, which is also elucidated on its economic and environmental sustainability. Moreover, the prospective advantages, limitations and challenges for future scale-up of FW-based ML production have also been outlined, together with the perspectives and directions forward.

The migration regularity and removal mechanism of antibiotic resistance genes during in situ enzymatic hydrolysis and anaerobic digestion of food waste.

This study developed a high efficiency compound enzyme (fungal mash) produced in situ from food waste (FW) used for improving hydrolysis and anaerobic digestion (AD) efficiency of FW. Results showed that the soluble COD and methane yield were respectively increased by 67.80% and 16.58% after 24 h in situ enzymatic hydrolysis of food waste by fungal mash. Furthermore, most of target ARGs in FW were also reduced by 45-94% after 24 h in situ enzymatic hydrolysis, while the total tested ARGs and intI1 were respectively further removed by 44-55% and 21-73% in subsequent AD process. In-depth analysis showed that fungal mash could effectively reduce potential hosts and control the horizontal transfer of ARGs during the in situ enzymatic hydrolysis and AD process. Ultimately, correlation analysis and redundancy analysis indicated that the evolution of bacterial communities and changes in intI1 where the common driving forces for the fate of ARGs.

Stability and nutrients removal performance of a Phanerochaete chrysosporium-based aerobic granular sludge process by step-feeding and multi A/O conditions.

A Phanerochaete chrysosporium-based aerobic granular sludge (PC-AGS) was developed by inoculating fungal mycelial pellets into a lab-scale aerobic granular sequencing batch reactor (AGSBR). A strategy using step-anaerobic feeding coupled with multi A/O conditions was adopted. The results showed that the removal efficiencies for total phosphorus (TP) and total inorganic nitrogen (TIN) were 94.56 ± 2.92% and 75.20 ± 7.74%, respectively, under relatively low aeration time. Compared with original AGS, the content of extracellular proteins for PC-AGS obviously increased from 18.61 to 41.44 mg/g MLSS by the end of phase I. Moreover, the mature granules had a larger size and better stability during the 100 days operation. Furthermore, the analysis of microbial diversity detected many key functional groups in PC-AGS granules that were beneficial to nutrients removal. This work demonstrated that the addition of fungal pellets not only enhanced the removal performance, but also improved the stability of the AGS system.

Carbon Fiber Reinforced Carbon-Al-Cu Composite for Friction Material.

A carbon/carbon-Al-Cu composite reinforced with carbon fiber 2.5D-polyacrylonitrile-based preforms was fabricated using the pressureless infiltration technique. The Al-Cu alloy liquids were successfully infiltrated into the C/C composites at high temperature and under vacuum. The mechanical and metallographic properties, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS) of the C/C-Al-Cu composites were analyzed. The results showed that the bending property of the C/C-Al-Cu composites was 189 MPa, whereas that of the pure carbon slide material was only 85 MPa. The compressive strength of C/C-Al-Cu was 213 MPa, whereas that of the pure carbon slide material was only 102 MPa. The resistivity of C/C-Al-Cu was only 1.94 µΩm, which was lower than that of the pure carbon slide material (29.5 µΩm). This finding can be attributed to the "network conduction" structure. Excellent wettability was observed between Al and the carbon matrix at high temperature due to the existence of Al4C3. The friction coefficients of the C/C, C/C-Al-Cu, and pure carbon slide composites were 0.152, 0.175, and 0.121, respectively. The wear rate of the C/C-Al-Cu composites reached a minimum value of 2.56 × 10-7 mm³/Nm. The C/C-Al-Cu composite can be appropriately used as railway current collectors for locomotives.

Synthesis and antibacterial activities of Yanglingmycin analogues.

The synthesis of Yanglingmycin and its enantiomer, along with eighteen Yanglingmycin analogues is reported. The structures were confirmed mainly by analyses of NMR spectral data. Antibacterial activity assays showed that Yanglingmycin and some of its analogues exhibited significant antibacterial activities against two important agricultural pathogenic bacteria, Ralstonia solanacearum and Pseudomonas syringae pv. actinidiae, with minimum inhibitory concentration (MIC) values ranging from 3.91 to 15.62 µg/mL. The antibacterial activities exhibited by Yanglingmycin and its analogues are promising, suggesting potential in the development of compounds for novel bactericides.

Synthesis and Antibacterial Activities of Yanglingmycin Analogues.

The synthesis of Yanglingmycin and its enantiomer, along with eighteen Yanglingmycin analogues is reported. The structures were confirmed mainly by analyses of NMR spectral data. Antibacterial activity assays showed that Yanglingmycin and some of its analogues exhibited significant antibacterial activities against two important agricultural pathogenic bacteria, Ralstonia solanacearum and Pseudomonas syringae pv. actinidiae, with MIC values ranging from 3.91 to 15.62 µg/mL. The antibacterial activities exhibited by Yanglingmycin and its analogues are promising, suggesting potential in the development of compounds for novel bactericides.

Synthesis and insecticidal activities of novel nitrogenous derivatives of celangulin-V.

In order to develop new biorational pesticides and clarify the potential structural factors needed for the biological activity of celangulin-V analogues, thirty novel nitrogenous derivatives were designed and synthesized. The single crystal structure of celangulin-V is reported for the first time and provides a more accurate structure than that previously reported. The structures of all the new derivatives were confirmed by either NMR or ESI-MSn analysis. Insecticidal activities of these compounds were tested against the third-instar larvae of Mythimna separata. One derivative (1-6) showed higher insecticidal activity than celangulin-V, with a KD50 of 231.2 microg.g(-1), while two compounds (2-13 and 2-14) exhibited lower insecticidal activities; the others revealed no activity at a concentration of 20 mg mL(-1). The results support the view that celangulin-V has the potential to be a lead structure of semi-synthetic green insecticides.