关键词： life cycle assessment   bioplastics   orchard waste   L-polylactic acid   poly(3-hydroxybutyrate)  

摘要： Life cycle assessment of a technology is the key to technological development in the context of sustainable development. Orchard waste has been identified as a potential source of bioplastics. The objective of this study was to conduct a life cycle assessment of two specific bioplastic materials, namely, L-polylactic acid (PLA) and poly(3-hydroxybutyrate) (PHB). Bioplastics, such as PLA acid and PHB, can be used as alternatives to conventional plastics due to their biodegradability and non-toxicity, both of which have the potential to replace conventional petroleum-based plastics. Polylactic acid was synthesized from orchard waste in a series of stages, including biomass processing, pretreatment for carbohydrate extraction, simultaneous saccharification and fermentation (SSF), and microwave polymerization. PHB, another biodegradable polymer, is produced by microorganisms through the fermentation of sugars obtained from the same biomass. Applied LCAs show that for PLA production, the stages having the greatest environmental impact are biomass processing, pretreatment, and the SSF process, and for PHB production, very energy-intensive stages significantly contributing to the environmental impacts are biomass processing and pretreatment stages. For both PLA and PHB, the initial stages of biomass processing and pretreatment are the most energy-intensive and significant contributors to CO2 emissions.

关键词： Microalgae   Transcriptomics   Genetic engineering   Algal biotechnology   Bio plastic   PHB  

摘要： The marine diatom Phaeodactylum tricornutum is an emerging host for metabolic engineering, but little is known about how introduced pathways are integrated into the existing metabolic framework of the host or influence transgene expression. In this study, we expressed the heterologous poly-3-hydroxybutyrate (PHB) pathway using episomal expression, which draws on the precursor acetyl coenzyme-A (AcCoA). By experimentally perturbing cultivation conditions, we gained insight into the regulation of the endogenous metabolism in transgenic lines under various environmental scenarios, as well as on alterations in AcCoA flux within the host cell. Biosynthesis of PHB led to distinct shifts in the metabolome of the host, and further analysis revealed a condition-dependent relationship between endogenous and transgenic metabolic pathways. Under N limitation, which induced a significant increase in neutral lipid content, both metabolic and transcriptomic data suggest that AcCoA was preferably shunted into the endogenous pathway for lipid biosynthesis over the transgenic PHB pathway. In contrast, supply of organic carbon in the form of glycerol supported both fatty acid and PHB biosynthesis, suggesting cross-talk between cytosolic and plastidial AcCoA precursors. This is the first study to investigate the transcriptomic and metabolomic response of diatom cell lines expressing a heterologous multi-gene pathway under different environmental conditions, providing useful insights for future engineering attempts for pathways based on the precursor AcCoA.

关键词： Biogenic   Bioimaging   Nanoparticles   PHAs   PHB  

摘要： Biogenic nanoparticles (NPs) have emerged as promising therapeutic formulations in effective drug delivery. Despite of various positive attributes, these NPs are often conjugated with various cytotoxic organic fluorophores for bioimaging, thereby reducing its effectiveness as a potential carrier. Herein, we aim to formulate biogenic fluorescent pigmented polyhydroxybutyrate (PHB) NPs from Rhodanobacter sp. strain KT31 (OK001852) for drug delivery. The bacterial strain produced 0.5 g L-1 of polyhydroxyalkanoates (PHAs) from 2.04 g L-1 of dry cell weight (DCW) under optimised conditions via submerged fermentation. Further, structural, thermal, and morphological charactersiation of the extracted PHAs was conducted using advance analytical technologies. IR spectra at 1719.25 cm(-1) confirmed presence of C = O functional group PHB. NMR and XRD analysis validated the chemical structure and crystallinity of PHB. TG-DTA revealed Tm (168 degrees C), Td (292 degrees C), and Xc (35%) of the PHB. FE-SEM imaging indicated rough surface of the PHB film and the biodegradability was confirmed from open windro composting. WST1 assay showed no significant cell death (> 50%) from 100 to 500 mu g/mL, endorsing non-cytotoxic nature of PHB. PHB NPs were uniform, smooth and spherical with size distribution and mean zeta potential 44.73 nm and 0.5 mV. IR and XRD peaks obtained at 1721.75 cm(-1) and 48.42 & Aring;denoted C = O and crystalline nature of PHB. Cell proliferation rate of PHB NPs was quite significant at 50 mu g/mL, establishing the non-cytotoxic nature of NPs. Further, in vitro efficacy of the PHB NPs needs to be evaluated prior to the biomedical applications.

摘要： Glucose sensing and metabolic adaptation to glucose availability in the tumor microenvironment are critical for cancer development. Here we show that HKDC1, a hexokinase highly expressed in cancer associated with poor prognosis, functions as a glucose sensor that alters its stability in response to environmental glucose. The glucose-sensing domain is located between amino acids 751-917, with Ser896 as a key residue that regulates HKDC1 stability by affecting Lys620 ubiquitination. This sensing mechanism enables cellular adaptation to glucose starvation by promoting mitochondrial fatty acid utilization. Furthermore, HKDC1 promotes tumor growth by sequestering prohibitin 2 (PHB2) to disable its suppressive effect on SP1, thus promoting the expression of pro-oncogenic molecules. Abrogation of HKDC1 by genetic knockout or by glucose depletion releases PHB2, leading to suppression of cancer cell proliferation and inhibition of tumor growth. Our study reveals a previously unrecognized role of HKDC1 in glucose sensing and metabolic adaptation, and identifies HKDC1 as a potential therapeutic target.

关键词： Halomonas   Gamma-Aminobutyric Acid   2-Pyrrolidone   PHB   Metabolic engineering  

摘要： Gamma-Aminobutyric acid (GABA) is a derivative of L-glutamate, also a precursor for the synthesis of 2-pyrrolidone, which is a monomer of nylon-4. This study achieved a one-step biosynthesis of GABA and 2-pyrrolidone by Halomonas bluephagenesis overexpressing key genes involved in GABA and 2-pyrrolidone synthesis and deleting GABA degradation genes combined with reducing the degradation of 2-pyrrolidone precursor. The resulting H. bluephagenesis strain WLp07 was employed in whole-cell catalysis, producing 357 g/L of GABA and 72 wt% of PHA. Furthermore, a self-flocculating H. bluephagenesis allowed rapid, convenient recycling of the cells, achieving 880 g/L of GABA over three cycles. Shake flask studies showed that engineered H. bluephagenesis harboring beta-alanine CoA transferase was able to synthesized 2-pyrrolidone from GABA. H. bluephagenesis as a chassis of next generation industrial biotechnology (NGIB), demonstrated its diverse ability to produce GABA and 2-pyrrolidone in addition to intracellular PHA.

关键词： 零价铁   厌氧氨氧化   生活污水   脱氮   除磷  

摘要： 为实现生活污水高效同步脱氮除磷，构建了零价铁耦合厌氧氨氧化系统，探究了零价铁对厌氧氨氧化短期脱氮除磷效能、颗粒污泥特性和关键酶活性的影响，并对系统高效同步脱氮除磷机理进行了分析。结果表明，当零价铁投加量为1 g，温度为35 ℃，反应12 h后，氨氮、总氮和总磷浓度分别为0.82 mg/L、5.36 mg/L和0.66 mg/L，总氮和总磷去除率分别比对照组高出14.8%和70.3%。此时颗粒污泥表面覆盖了少量的零价铁及其氧化物和沉淀物，颜色变黑，质地变硬，结构强度增大，铁元素占比达到35.4%。颗粒污泥中松散结合型EPS减少，紧密结合型EPS增加，有利于提高颗粒污泥的沉降性能和抵御外界不利因素的影响。颗粒污泥表面的羟基和羰基等含氧官能团增加，促进了厌氧氨氧化系统中的新陈代谢活动。厌氧氨氧化系统中硝酸还原酶、亚硝酸还原酶和联氨合成酶活性增加，从而提高了系统的脱氮效能。该研究可为生活污水中氮磷的高效低碳同步去除提供理论基础。

关键词： 污水处理水质预测   事件触发   模糊神经网络   马尔科夫决策   性能势函数  

摘要： 针对污水处理过程非平稳性、多工况性导致的水质难以高效、精准预测的问题， 提出了一种事件触发的模糊神经网络(Event-triggered fuzzy neural network， ETFNN)总磷预测模型设计方法，以事件的形式感知污水处理总磷状态演化过程的非平稳性和多工况性，进而实现对总磷状态高效、精准的跟踪和预测。首先，利用总磷历史数据对模糊神经网络(Fuzzy Neural Network， FNN)进行训练，根据能够反映多工况切换的训练误差变化趋势来定义事件；其次，设计事件触发的模型参数更新策略，当不同事件发生时，模型会触发变步长的参数更新行为，即实现对污水处理运行非平稳性、多工况性的感知和识别；同时，本文通过构造等效马尔科夫决策过程的性能势函数证明了ETFNN模型学习过程的收敛性；最后，将ETFNN作为软测量模型，用于实际污水处理过程出水总磷建模与预测，并进行了综合分析。实验结果表明，所提出的ETFNN软测量模型不仅能提高总磷预测精度，还能以事件的形式识别并跳过无效数据，进而降低预测模型的计算复杂度。

关键词： 污水处理   减污降碳   成本   协同指数   相关性分析  

摘要： 随着城镇化的不断推进，中国污水处理设施建设发展迅速，但缺乏针对污水处理厂减污降碳协同性研究。为量化污水处理厂减污降碳协同效应，构建了污水处理厂减污降碳协同绩效评价体系，运用耦合协调模型计算污染物削减、碳减排和成本控制系统的协同指数，并评价了中国南方640座污水处理厂的减污降碳协同效果，最后通过Spearman相关系数对减污降碳协同指数的影响因素进行进一步研究。结果表明：①A2/O工艺污水处理厂在污染物削减方面表现最佳，单位污水污染物削减量较高；A2/O工艺和SBR类工艺的污水处理厂单位污水碳排放强度较低，展现出良好的碳减排效果；≥5万t·d–1规模的污水处理厂单位污水治理成本最低，表现出较强的成本控制能力。②接近80%污水处理厂实现了较好的减污降碳协同效果，达到了高度协调水平，尤其是A2/O工艺的污水处理厂；污水处理厂规模越大，减污降碳协同效果越好。③减污降碳协同指数与污染物指标呈正相关关系，而与碳排放强度和成本指标呈负相关关系；单位污水污染物综合削减量是正相关最强的指标，而单位污水治理成本是负相关最强的指标。研究显示，污水处理厂在污染物达标排放的基础上，亟需在碳排放和成本控制方面制定节能绿色转型路径与措施。

关键词： 农村   生活污水处理站   绿色设计  

摘要： 随着经济水平的持续提高,农村居民的生活方式也日益多元化,这导致农村生活用水需求急剧上升、污水产量随之增加.若缺乏针对性的处理措施,污水将随意排放,进而对农村生态环境造成破坏.因此,为确保农村地区的环境质量,必须秉承绿色环保理念,规划建设专门的农村生活污水处理站,以确保农村生活污水能够以环保的方式得到处理,避免对农村生态造成负面影响.基于此,本文将结合实际案例,深入分析农村生活污水处理站设计中的关键要素.