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摘要： Genome-scale, constraint-based models (GEM) and their derivatives are commonly used to model and gain insights into microbial metabolism. Often, however, their accuracy and predictive power are limited and enable only approximate designs. To improve their usefulness for strain and bioprocess design, we studied here their capacity to accurately predict metabolic changes in response to operational conditions in a bioreactor, as well as intracellular, active reactions. We used flux balance analysis (FBA) and dynamic FBA (dFBA) to predict growth dynamics of the model organism Saccharomyces cerevisiae under different industrially relevant conditions. We compared simulations with the latest developed GEM for this organism (Yeast8) and its enzyme-constrained version (ecYeast8) herein described with experimental data and found that ecYeast8 outperforms Yeast8 in all the simulations. EcYeast8 was able to predict well-known traits of yeast metabolism including the onset of the Crabtree effect, the order of substrate consumption during mixed carbon cultivation and production of a target metabolite. We showed how the combination of ecGEM and dFBA links reactor operation and genetic modifications to flux predictions, enabling the prediction of yields and productivities of different strains and (dynamic) production processes. Additionally, we present flux sampling as a tool to analyse flux predictions of ecGEM, of major importance for strain design applications. We showed that constraining protein availability substantially improves accuracy of the description of the metabolic state of the cell under dynamic conditions. This therefore enables more realistic and faithful designs of industrially relevant cell-based processes and, thus, the usefulness of such models.

关键词： Lactobionic acid   Acid whey   Lactose oxidation   Pseudomonas taetrolens  

摘要： Acid whey causes a major disposal problem for the dairy industry due to its low pH and high salt concentration. Lactobionic acid (LBA) production by whey fermentation is an inexpensive process. The goal of this work was to employ acid whey for LBA production. Acid whey was fermented in a bioreactor, adding Pseudomonas taetrolens LMG 2336 at 30 degrees C and 6.5 pH, with 1.5-Lpm oxygen aeration and 350-rpm agitation. Three fermentation tests were carried out with a different amount of inoculum (10%, 30% and 10% three times within 24 h). Results indicated that repeatedly adding P. taetrolens inoculum to the acid whey substrate allows a complete lactose conversion into LBA, while the lactose oxidation process was insufficient in the sample where the inoculum was only added at the beginning of the fermentation process (only 29.7% LBA production with 10% inoculum). The physiological heterogeneity of P. taetrolens was determined by multiparametric flow cytometry, and results showed that there was a phenotypic adaptation of the microorganism due to the changes observed in its heterogeneity and physiological state. The results achieved will help to recycle acid whey for value-added product production such as LBA production.

关键词： Immersion frequency   Phenylethanoids   Polyphenolic acid   Salvia viridis   Shoot culture   Temporary immersion system  

摘要： Salvia viridis is a rich source of pharmacologically-important polyphenolic compounds with anti-inflammatory, antioxidant and anticancer activities. The aim of the present study was to optimise the large-scale cultivation of sage shoots in the Plantform bioreactor. It evaluated the effect of culture duration (two or three weeks), the use of a semi-continuous system and the immersion frequency in a liquid medium (every 80 or 170 min) on the growth and accumulation of secondary metabolites. The content of bioactive phenolic acids and phenylethanoids in the obtained material was determined using HPLC. The most efficient growth parameters, expressed as fresh (26.99 g) and dry weight (3.51 g) as well as proliferation ratio (18.6), were observed for shoots grown in a fed-batch system, immersed every 80 min;this approach yielded a 33-fold biomass increase within four weeks. However, the most efficient production of bioactive compounds was achieved for shoots grown for three weeks in a batch system, immersed every 80 min: total phenolic acid, total phenylethanoid and total phenol contents of 18.3, 11.4 and 29.7 mg/g DW. In these conditions, within three weeks, total phenolic acid level was almost 10 times higher than that found in the aerial parts of four-month-old soil-grown plants with a similar phenylethanoid level. Hence, the described S. viridis shoot culture cultivated in the Plantform bioreactor may be an alternative efficient source of plant material rich in valuable compounds. Key message Optimization of culture conditions (culture duration, the use of fed-batch mode, frequency of the medium application) for growth and productivity of bioactive compounds in Salvia viridis shoots cultivated in the Plantform bioreactor.

摘要： Bacterial outer membrane (OM) is a self-protective and permeable barrier, while having many non-negligible negative effects in industrial biotechnology. Our previous studies revealed enhanced properties of Halomonas bluephagenesis based on positive cellular properties by OM defects. This study further expands the OM defect on membrane compactness by completely deleting two secondary acyltransferases for lipid A modification in H. bluephagenesis, LpxL and LpxM, and found more significant advantages than that of the previous lpxL mutant. Deletions on LpxL and LpxM accelerated poly(3-hydroxybutyrate) (PHB) production by H. bluephagenesis WZY229, leading to a 37% increase in PHB accumulation and 84-folds reduced endotoxin production. Enhanced membrane permeability accelerates the diffusion of gamma-butyrolactone, allowing H. bluephagenesis WZY254 derived from H. bluephagenesis WZY229 to produce 82wt% poly(3-hydroxybutyrate-co-23mol%4-hydroxybutyrate) (P(3HB-co-23mol%4HB)) in shake flasks, showing increases of 102% and 307% in P(3HB-co-4HB) production and 4HB accumulation, respectively. The 4HB molar fraction in copolymer can be elevated to 32 mol% in the presence of more gamma-butyrolactone. In a 7-l bioreactor fed-batch fermentation, H. bluephagenesis WZY254 supported a 84 g l(-1) dry cell mass with 81wt% P(3HB-co-26mol%4HB), increasing 136% in 4HB molar fraction. This study further demonstrated that OM defects generate a hyperproduction strain for high 4HB containing copolymers.

关键词： 17 beta-Estradiol removal   Denitrification   Manganese-oxidation   Immobilized bioreactor   Microbial community structure  

摘要： The coexistence of nitrate and endocrine substances (EDCs) in groundwater is of global concern. Herein, an efficient and stable polypyrrole@corn cob (PPy@Corn cob) bioreactor immobilized with Zoogloea sp. was designed for the simultaneous removal of 17 beta-estradiol (E2), nitrate and Mn(II). After 225 days of continuous operation, the optimal operating parameters and enhanced removal mechanism were explored, also the longterm toxicity and microbial communities response mechanisms under E2 stress were comprehensively evaluated. The results showed that the removal efficiencies of E2, nitrate, and Mn(II) were 84.21, 82.96, and 47.91%, respectively, at the optimal operating conditions with hydraulic retention time (HRT) of 8 h, pH of 6.5 and Mn(II) concentration of 20 mg L-1. Further increased of initial E2 (2 and 3 mg L-1) resulted in the inhibiting effect of denitrification and manganese oxidation, but excellent E2 removal efficiencies maintained, which were associated with the formation and continuous accumulation of biomanganese oxides (BMO). Characterization analysis of biological precipitation demonstrated that adsorption and redox conversion on the BMO surface played key roles in the removal of E2. In addition, different levels of E2 exposure are decisive factors in community evolution, and bioaugmented bacterial communities with Zoogloea as the core group can dynamically adapt to E2 stress. This study offers the possibility to better utilize microbial metabolism and to advance opportunities that depend on microbial physiology and material characterization applications.

摘要： Anaerobic membrane bioreactor (AnMBR) technology is increasingly researched for wastewater treatment in a circular economy scenario to recover nutrients, water, and biogas. AnMBR couples the advantages of anaerobic digestion, such as low sludge production, no aeration requirement and biogas production, with the benefits of membrane technology, that is, complete solids removal and a high removal degree of pathogenic organisms. Nevertheless, membrane fouling remains the major operational challenge, limiting the economic feasibility and applicability of AnMBRs. Membrane fouling is responsible for lower flux, higher transmembrane pressure, the need for intensive biogas sparging or increased crossflow velocities for membrane scouring, and increased frequency of membrane cleaning and membrane replacement; consequently, increasing energy and operational costs. Researchers extensively studied the causes and mitigation of membrane fouling in both aerobic and anaerobic membrane bioreactors. Membrane fouling mitigation strategies have focused on optimisation of membrane operational variables, such as: gas sparging, crossflow velocity, filtration-relaxation cycle, permeate flux and frequency and intensity of chemical cleaning. Although optimisation of operational variables might be suitable when the sludge has good or moderate filterability, it may not be adequate or sufficient when fouling is caused by a sludge with poor filterability. The application of flux enhancers for fouling control has been extensively investigated. Flux enhancers are adsorbents, coagulants and flocculants that decrease fouling by changing the sludge characteristics, thereby improving sludge filterability. Particularly, cationic polymers have been successfully applied as flux enhancers in short-term tests on large-scale aerobic membrane bioreactors (MBRs), whereas in AnMBRs research is scarce, and so far, only done at lab-scale. Results from MBRs cannot be directly translated to AnMBRs because the exten

关键词： 生物反应器   生物医药   全生命周期  

摘要： 随着全球生物医药产业的高速发展,生物反应器在生物医药的全生命周期中起到了越来越重要的作用。本文论述了生物医药中生物反应器的工作体积、材质和原理,为促进生物反应器的研究与开发提供一定的参考。

关键词： 微藻   固碳技术   生物固碳   碳减排   负排放技术   光生物反应器  

摘要： 我国承诺,2030年实现碳达峰,2060年达到碳中和,为实现这个目标,负排放技术是实现目标不可或缺的技术。微藻生物固碳技术是负排放技术之一。文章从微藻藻种、生产设备和微藻固碳技术的研究和应用情况等方面进行了分析,旨为行业内外的相关从业人员提供参考。

关键词： 垃圾填埋场   渗滤液回灌   生物反应器   产甲烷  

摘要： 填埋是垃圾处理处置最常见的手段。随着生物反应器型填埋场的广泛应用,渗滤液回灌作为其中一项关键技术发挥着重要作用。渗滤液回灌在加速填埋场稳定化、加速填埋场沉降和提高产甲烷气量等方面具有关键作用。本文主要回顾了渗滤液回灌技术在垃圾填埋场中增大甲烷产量的研究历程,阐述了渗滤液回灌至垃圾填埋场可促进产甲烷的机理及影响因素。渗滤液回灌技术提高了甲烷产量,若是将甲烷气体加以收集利用,可减少化石燃料的燃烧,实现废物的资源再利用,从而得到较好的社会效益。

关键词： 膜炭生物反应器   表面活性剂废水   厌氧生化   好氧生化  

摘要： 开发了一种膜炭生物反应器,并研究其降解表面活性剂废水的效果,与膜生物反应器相比,该系统耐表面活性剂冲击能力强,在表面活性剂负荷不超过 0.126 kg/(m^(3)·d)时,进水 COD 为 1 600~4 500 mg/L,LAS 为 200~1 300mg/L 时,MCBR 出水 COD 稳定在 100 mg/L 以下,LAS 小于 1 mg/L,去除率接近 100%。氨氮平均去除率 85% 以上,总氮去除率在 9.47%~47.74%,系统同时存硝化与反硝化作用。粉末活性炭强化了物理吸附-厌氧生化降解过程,实现了表面活性剂停留时间和水力停留时间分离,有利于难生化物质的降解。该系统的突出优点为在处理高浓度表面活性剂废水过程中无泡沫产生,避免污泥流失,表面活性剂一步去除率超过 99%。