Bioresource Technology最新文献

Low humification and nitrogen loss pose substantial challenges to the resource utilization in kitchen waste composting. This study investigated the effects of brown-rot fungi (BRF), cellulolytic nitrogen fixing bacteria (CNFB), and their composite microbial inoculants (CMI) during composting. Results indicated that microbial inoculants extended the thermophilic phase and enhanced cellulose degradation. Compared with the control, the degree of polymerization (HA/FA) in BRF, CNFB, and CMI was 2.28, 1.85, and 2.68 times higher, respectively, while increasing total nitrogen by 11.15%, 15.50%, and 19.73%. BRF and CMI primarily enhanced the Maillard humification pathway, while CNFB promoted the polyphenol humification pathway. Additionally, BRF enhanced nitrification and reduced denitrification, whereas CNFB and CMI improved nitrification, nitrogen fixation, and ammonification while reducing denitrification. Overall, BRF primarily promoted humification, while CNFB excelled in nitrogen retention. The CMI achieved optimal humification and nitrogen retention, indicating a potential sustainable solution for kitchen waste composting.

A novel two-stage carbon sequestration strategy (3 % and 10 % CO₂) was developed and its feasibility was comprehensively demonstrated by multiple methods (pilot-scale cultivation, kinetics, economics and carbon fixation analysis). It was also a safe, efficient and low-cost harvesting strategy. At the end of the culture, astaxanthin production and content increased 2.3 and 2.2 times, respectively. Sedimentation rate (SR) was introduced for the first time to evaluate microalgae culture methods. The SR reached 82.2 % after 2 h of standing. Pilot-scale cultivation was achieved outdoors, with the optimal photobioreactor being a 40 L tubular photobioreactor (T-PBRs), which individually achieved 3.1 g/L and 2.3 % biomass and astaxanthin content. The maximum rate of carbon sequestration (227.9 mg/L/d) was observed in 40 L T-PBRs. The cost of producing 1 kg of astaxanthin-enriched Haematococcus pluvialis (H. pluvialis) was only 17.5 USD. This study brings new perspectives to carbon sequestration and the development of astaxanthin markets.

Recent research has discussed the positive impacts of metal-based nanoparticles (NPs) on bioprocesses producing either hydrogen (H₂) or methane (CH₄). The enhancement has been explained by mechanisms such as direct interspecies electron transfer (DIET), metal corrosion, and dissimilatory reduction. Such interactions could induce further benefits, such as controlling oxidation-reduction potential (ORP), mitigating toxicants, promoting enzymatic activity, and altering the microbiome, which have not yet been comprehensively discussed. Factors like metal type, oxidation state, and size of NPs are crucial for their reactivity and corresponding responses. This review discusses how different redox potentials of metals can regulate metabolic pathways and how NPs and their reactive ions can eliminate toxicants (e.g., sulfate) and enhance the activity of intra- and extracellular enzymes. The enrichment of responsive microorganisms in correlation with NPs is further discussed. A better understanding of the multifaceted role of metal-based NPs can guide potential new incorporation strategies to improve bioprocesses.

Syngas fermentation using acetogenic bacteria offers a promising route for sustainable chemical production. However, gas-liquid mass transfer limitations and efficient co-utilization of CO and H₂ pose significant challenges. This study investigated the kinetics of syngas conversion to acetate by Acetobacterium wieringae and Clostridium species in batch conditions under varying initial CO partial pressures (19 - 110 kPa) in batch cultures. A. wieringae strains, exhibited superior growth in all gas compositions, with a maximum growth rate of 0.104 h^-1. The distinct CO, H₂, and CO₂ consumption patterns revealed metabolic flexibility and adaptation to varying syngas compositions. Notably, A. wieringae strains and C. autoethanogenum achieved complete CO and H₂ conversion, with C. autoethanogenum also exhibiting net CO₂ uptake. These findings provide valuable insights into the distinct metabolic capabilities of these acetogens and contribute to the development of efficient and sustainable syngas fermentation processes.

This paper thoroughly examines how policy incentives impact the economic and environmental sustainability of anaerobic digestion (AD) systems. It uses techno-economic and life cycle analyses, along with real industry data, to explore the entire AD process-from feedstock acceptance to digestate disposal. It evaluates the effects of various U.S. policy crediting programs on the economic viability of different AD pathways for treating sewage sludge and food waste. Tipping fees are identified as the primary driver of profitability, while policy credits play a crucial role in enhancing economic feasibility, particularly for renewable natural gas production. However, future regulatory changes could reshape this economic landscape. All AD pathways are found to significantly reduce greenhouse gas emissions, though economic outcomes are highly sensitive to digestate disposal costs and feedstock tipping fees. Co-digestion with food waste is proposed as a strategy to reduce dependence on policy credits and improve long-term economic stability.