利用废弃物原料生产燃料乙醇的研究进展

乙醇是一种十分重要的工业用途的化工原料。目前国内外学者纷纷采用不同的方法和手段对乙醇发酵进行研究,目前,利用废弃物为原料生产乙醇是热点。本文阐述了利用各种废弃原料生产乙醇的必要性,并分别论述了利用纤维质废弃物、淀粉质废弃物、糖质废弃物等生产乙醇的研究进展,着重论述了利用纤维质废弃物的生产情况,提出了需进一步研究和解决的问题。     

An Indicator to Evaluate the Thermodynamic Maturity of Industrial Process Units in Industrial Ecology

The article suggests a measure to evaluate the thermodynamic maturity of industrial systems at the level of single process units. The measure can be quantified with reasonable confidence on the basis of entropy production as defined by irreversible thermodynamics theory. It quantifies, for one process unit, the distance between its actual state of operation and its state with minimum entropy production or optimum exergy efficiency, when the two states are constrained with a fixed production capacity of the process unit. We suggest that the minimum entropy production state is a mature state, or that processes that operate at this state are mature. We propose to call the measure "the thermodynamic maturity indicator" (π), and we define it as the ratio between the minimum entropy production and the actual entropy production. We calculated π on the basis of literature data for some examples of industrial process units in the chemical and process industry (i.e., heat exchanger, chemical reactor, distillation column, and paper drying machine). The proposed thermodynamic measure should be of interest for industrial ecology because it emerges from the entropy production rate, a dynamic function that can be optimized and used to understand the thermodynamic limit to improving the exergy efficiency of industrial processes. Although not a tool for replacing one process with another or comparing one technology to another, π may be used to assess actual operation states of single process units in industrial ecology.     

Microbial keratinases: industrial enzymes with waste management potential

Proteases are ubiquitous enzymes that occur in various biological systems ranging from microorganisms to higher organisms. Microbial proteases are largely utilized in various established industrial processes. Despite their numerous industrial applications, they are not efficient in hydrolysis of recalcitrant, protein-rich keratinous wastes which result in environmental pollution and health hazards. This paved the way for the search of keratinolytic microorganisms having the ability to hydrolyze “hard to degrade” keratinous wastes. This new class of proteases is known as “keratinases”. Due to their specificity, keratinases have an advantage over normal proteases and have replaced them in many industrial applications, such as nematicidal agents, nitrogenous fertilizer production from keratinous waste, animal feed and biofuel production. Keratinases have also replaced the normal proteases in the leather industry and detergent additive application due to their better performance. They have also been proved efficient in prion protein degradation. Above all, one of the major hurdles of enzyme industrial applications (cost effective production) can be achieved by using keratinous waste biomass, such as chicken feathers and hairs as fermentation substrate. Use of these low cost waste materials serves dual purposes: to reduce the fermentation cost for enzyme production as well as reducing the environmental waste load. The advent of keratinases has given new direction for waste management with industrial applications giving rise to green technology for sustainable development.     

Waste to bioproduct conversion with undefined mixed cultures: the carboxylate platform

Our societies generate increasing volumes of organic wastes. Considering that we also need alternatives to oil, an opportunity exists to extract liquid fuels or even industrial solvents from these abundant wastes. Anaerobic undefined mixed cultures can handle the complexity and variability of organic wastes, which produces carboxylates that can be efficiently converted to useful bioproducts. However, to date, barriers, such as inefficient liquid product separation and persistence of methanogens, have prevented the production of bioproducts other than methane. Here, we discuss combinations of biological and chemical pathways that comprise the 'carboxylate platform', which is used to convert waste to bioproducts. To develop the carboxylate platform into an important system within biorefineries, we must understand the kinetic and thermodynamic possibilities of anaerobic pathways, understand the ecological principles underlying pathway alternatives, and develop superior separation technologies.     

Global Phosphorus Flows in the Industrial Economy From a Production Perspective

Human activity has quadrupled the mobilization of phosphorus (P), a nonrenewable resource that is not fully recycled biologically or industrially. P is accumulated in both water and solid waste due to fertilizer application and industrial, agricultural, and animal P consumption. This paper characterizes the industrial flows, which, although smaller than the agricultural and animal flows, are an important phosphorus source contributing to the pollution of surface waters. We present the quantification of the network of flows as constrained by mass balances of the global annual metabolism of phosphorus, based on global consumption for 2004, all of which eventually ends up as waste and in the soil and water systems. We find that on a yearly basis, 18.9 million metric tons (MMT) of P is produced, of which close to 75% goes to fertilizer and the rest to industrial and others uses. Phosphoric acid is the precursor for many of the intermediate and end uses of phosphate compounds described in this study and accounts for almost 80% of all P consumed. Eventually, all of the P goes to waste: 18.5 MMT ends up in the soil as solid waste, and 1.32 MMT is emissions to air and water. Besides quantifying P flows through our economy, we also consider some possible measures that could be taken to increase the degree of recovery and optimization of this resource and others that are closely related, such as the recovery of sulfur from gypsum and wastewater (sludge), and fluorine from wet phosphoric acid production.     

Analyzing the Environmental Benefits of Industrial Symbiosis

Studies of industrial symbiosis (IS) focus on the physical flows of materials and energy in local industrial systems. In an ideal IS, waste material and energy are shared or exchanged among the actors of the system, thereby reducing the consumption of virgin material and energy inputs, and likewise the generation of waste and emissions. In this study, the environmental impacts of an industrial ecosystem centered around a pulp and paper mill and operating as an IS are analyzed using life cycle assessment (LCA). The system is compared with two hypothetical reference systems in which the actors would operate in isolation. Moreover, the system is analyzed further in order to identify possibilities for additional links between the actors. The results show that of the total life cycle impacts of the system, upstream processes made the greatest overall contribution to the results. Comparison with stand‐alone production shows that in the case studied, the industrial symbiosis results in modest improvements, 5% to 20% in most impact categories, in the overall environmental impacts of the system. Most of the benefits occur upstream through heat and electricity production for the local town. All in all it is recommended that when the environmental impacts of industrial symbiosis are assessed, the impacts occurring upstream should also be studied, not only the impacts within the ecosystem.     

Engineering siderophore production in Pseudomonas to improve asbestos weathering

Iron plays a key role in microbial metabolism and bacteria have developed multiple siderophore-driven mechanisms due to its poor bioavailability for organisms in the environment. Iron-bearing minerals generally serve as a nutrient source to sustain bacterial growth after bioweathering. Siderophores are high-affinity ferric iron chelators, of which the biosynthesis is tightly regulated by the presence of iron. Pyoverdine-producing Pseudomonas have shown their ability to extract iron and magnesium from asbestos waste as nutrients. However, such bioweathering is rapidly limited due to repression of the pyoverdine pathway and the low bacterial requirement for iron. We developed a metabolically engineered strain of Pseudomonas aeruginosa for which pyoverdine production was no longer repressed by iron as a proof of concept. We compared siderophore-promoted dissolution of flocking asbestos waste by this optimized strain to that by the wild-type strain. Interestingly, pyoverdine production by the optimized strain was seven times higher in the presence of asbestos waste and the dissolution of magnesium and iron from the chrysotile fibres contained in flocking asbestos waste was significantly enhanced. This innovative mineral weathering process contributes to remove toxic iron from the asbestos fibres and may contribute to the development of an eco-friendly method to manage asbestos waste.     

Exploring the emergence of waste recovery and exchange in industrial clusters

Self-organized industrial symbiosis (IS) starts with one actor's decision to invest in a waste recovery plant and the other actors' decision to buy the recovered flow. Technical and institutional conditions of the cluster influence actors' decisions. This paper explores the emergence of IS collaborations in industrial clusters under different techno-economic conditions in the long term. We propose a mixed-integer linear programming model that incorporates costs and constraints associated with waste recovery and exchange to study actors' investment decisions and investigate shaped symbiotic exchanges under rising energy prices and limited electricity supply. The approach is implemented in Iran's Persian Gulf Mining and Metals Special Economic Zone as a case study. The results revealed that changes in internal or external condition simultaneously influence the industrial and waste recovery plants. For instance, increasing energy prices without raising product prices significantly decreased the production level of industrial plants and, consequently, heat recovery potential. Furthermore, the waste heat recovery plants' contribution to improving the cluster's economic and environmental performance was not the same. Electricity recovery from a power plant's waste heat can result in 55 PJ grid electricity intake reduction and 720 M€ cluster cash flow increase. Recovered cooling or electricity from the steelmaking plant waste heat was consumed internally rather than shaping IS. These model outcomes show its capability to study IS within the socio-technical structure of the cluster, not a standalone phenomenon. Implemented conceptualization offers a novel system-level approach, which could be adjusted to assess other industrial development strategies.     

Thermodynamic prediction of hydrogen production from mixed-acid fermentations

The MixAlco? process biologically converts biomass to carboxylate salts that may be chemically converted to a wide variety of chemicals and fuels. The process utilizes lignocellulosic biomass as feedstock (e.g., municipal solid waste, sewage sludge, and agricultural residues), creating an economic basis for sustainable biofuels. This study provides a thermodynamic analysis of hydrogen yield from mixed-acid fermentations from two feedstocks: paper and bagasse. During batch fermentations, hydrogen production, acid production, and sugar digestion were analyzed to determine the energy selectivity of each system. To predict hydrogen production during continuous operation, this energy selectivity was then applied to countercurrent fermentations of the same systems. The analysis successfully predicted hydrogen production from the paper fermentation to within 11% and the bagasse fermentation to within 21% of the actual production. The analysis was able to faithfully represent hydrogen production and represents a step forward in understanding and predicting hydrogen production from mixed-acid fermentations.     

Microbial valorization of underutilized and nonconventional waste streams

The growing burden of waste disposal coupled with natural resource scarcity has renewed interest in the remediation, valorization, and/or repurposing of waste. Traditional approaches such as composting, anaerobic digestion, use in fertilizers or animal feed, or incineration for energy production extract very little value out of these waste streams. In contrast, waste valorization into fuels and other biochemicals via microbial fermentation is an area of growing interest. In this review, we discuss microbial valorization of nonconventional, aqueous waste streams such as food processing effluents, wastewater streams, and other industrial wastes. We categorize these waste streams as carbohydrate-rich food wastes, lipid-rich wastes, and other industrial wastes. Recent advances in microbial valorization of these nonconventional waste streams are highlighted, along with a discussion of the specific challenges and opportunities associated with impurities, nitrogen content, toxicity, and low productivity.     

Rio Tinto as a niche for acidophilus enzymes of industrial relevance

Lignocellulosic residues are amongst the most abundant waste products on Earth. Therefore, there is an increasing interest in the utilization of these residues for bioethanol production and for biorefineries to produce compounds of industrial interest. Enzymes that breakdown cellulose and hemicellulose into oligomers and monosaccharides are required in these processes and cellulolytic enzymes with optimum activity at a low pH area are desirable for industrial processes. Here, we explore the fungal biodiversity of Rıo Tinto, the largest acidic ecosystem on Earth, as far as the secretion of cellulolytic enzymes is concerned. Using colorimetric and industrial substrates, we show that a high proportion of the fungi present in this extremophilic environment secrete a wide range of enzymes that are able to hydrolyze cellulose and hemicellulose at acidic pH (4.5–5). Shotgun proteomic analysis of the secretomes of some of these fungi has identified different cellulases and hemicellulolytic enzymes as well as a number of auxiliary enzymes. Supplementation of pre-industrial cocktails from Myceliophtora with Rio Tinto secretomes increased the amount of monosaccharides released from corn stover or sugar cane straw. We conclude that the Rio Tinto fungi display a good variety of hydrolytic enzymes with high industrial potential.     

Developing microbial biofilm as a robust biocatalyst and its challenges

Biocatalysts, such as bacteria, yeast, fungi and the enzymes they produce, have been used for many industrial applications since they function as effective and environmentally friendly tools. Whole cells have also been used in many sophisticated bioprocesses since a number of sequential reactions can be catalyzed within the cells. However, the use of whole cells in suspension in batch, fed-batch and continuous processes has some limitations. For instance, the cultures are non-reusable, they are sometimes sensitive to the toxicity of substrates or products, there can be issues with short-term stability, and each of these issues can impede biocatalyst regeneration, perturbing the downstream process and causing complexity in running large scale continuous culture. Recently, biofilms have emerged as a new generation of biocatalysts to solve these limitations in the production of many bio-based materials, including chemicals, antibiotics, enzymes, bioethanol, biohydrogen, and electricity production via microbial fuel cells. The establishment of industrial processes using biofilms has the potential for high benefit in terms of low-cost cell immobilization without the necessity of added polymers or chemicals. Many small-scale biofilm reactors have been developed for the production of value-added products, and it may be challenging to establish it on an industrial scale.     

Alkaliphiles — from an industrial point of view

Abstract: Organisms with pH optima for growth in excess of pH 9 are defined as alkaliphiles (or sometimes alkalophiles). Alkaliphiles contain prokaryotes, eukaryotes, and archaea. It is clear that many different taxa are represented among the alkaliphiles, and some of them are proposed as new taxa. Alkaliphiles can b isolated from normal environments such as garden soil, although counts of the alkaliphiles are higher in alkaline environments. Alkaliphiles have made a great impact in industrial applications. Biological detergents contain alkaline enzymes, such as alkaline cellulases and/or alkaline proteases that have been produced from alkaliphiles. The current proportion of total world enzyme production destined for the laundry detergents market exceeds 30%. Another important application is the industrial production of cyclodextrin with alkaline cyclomaltodextrin glucanotransferase. This enzyme reduced the production cost and paved the way for its use in large quantities in foodstuffs, chemicals and pharmaceuticals. Besides these applications, there are other possible applications in food and waste treatment industries.     

Homogeneous,heterogeneous and enzymatic catalysis for transesterification of high free fatty acid oil (waste cooking oil) to biodiesel: A review

In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel.     

A Material Flow‐based Approach to Enhance Resource Efficiency in Production and Recycling Networks

Resource and energy efficiency are key strategies for production and recycling networks. They can contribute to more sustainable industrial production and can help cope with challenges such as competition, rising resource and energy prices, greenhouse gas emissions reduction, and scarce and expensive landfill space. In pursuit of these objectives, further enhancements of single processes are often technologically sophisticated and expensive due to past achievements that have brought the processes closer to technical optima. Nevertheless, the potential for network‐wide advancements may exist. Methods are required to identify and assess the potential for promising resource and energy efficiency measures from technical, economic, and ecological perspectives. This article presents an approach for a material flow‐based techno‐economic as well as ecological analysis and assessment of resource efficiency measures in production and recycling networks. Based on thermodynamic process models of different production and recycling processes, a material and energy flow model of interlinked production and recycling processes on the level of chemical compounds is developed. The model can be used to improve network‐wide resource efficiency by analyzing and assessing measures in scenario and sensitivity analyses. A necessary condition for overcoming technical and economic barriers for implementing such measures can be fulfilled by identifying strategies that appear technologically feasible and economically and ecologically favorable. An exemplary application to a production and recycling network of the German steel and zinc industry is presented. From a methodological point of view, the approach shows one way of introducing thermodynamics and further technological aspects into industrial planning and assessment.     

Microbial diversity in support of anaerobic biomass valorization

Microbial diversity provides an immense reservoir of functions and supports key steps in maintaining ecosystem balance through matter decomposition processes and nutrient recycling. The use of microorganisms for biomolecule production is now common, but often involves single-strain cultures. In this review, we highlight the significance of using ecosystem-derived microbial diversity for biotechnological researches. In the context of organic matter mineralization, diversity of microorganisms is essential and enhances the degradation processes. We focus on anaerobic production of biomolecules of interest from discarded biomass, which is an important issue in the context of organic waste valorization and processing. Organic waste represents an important and renewable raw material but remains underused. It is commonly accepted that anaerobic mineralization of organic waste allows the production of diverse interesting molecules within several fields of application. We provide evidence that complex and diversified microbial communities isolated from ecosystems, i.e. microbial consortia, offer considerable advantages in degrading complex organic waste, to yield biomolecules of interest. We defend our opinion that this approach is more efficient and offers enhanced potential compared to the approaches that use single strain cultures.     

产业园区温室气体排放清单

温室气体排放所导致的全球气候变化是国际社会长期关注的热点问题,它严重限制了人类社会的发展并威胁着人类的生存。产业园区通常集中了一个区域主要的生产要素与生产能力,也代表着特定产业在该区域的发展水平,理应作为发展低碳经济的基础单元和减少温室气体排放的重要控制点,也可以成为解决区域资源、环境问题的突破口。明确了产业园区温室气体排放的系统边界和内部结构,梳理了产业园区全生命周期温室气体排放行为,综合考虑产业园区能源消耗、工业生产、物质材料消耗、仪器设备投入、废弃物处理处置、景观绿化等过程,建立产业园区温室气体排放核算方法,并对案例园区进行了清单分析。结果表明:案例园区整个生命周期的温室气体排放量为1872177 t CO2-eq,其中运行管理阶段占全生命周期排放的比例最高,为95.35%。建设阶段的温室气体排放总量中建筑材料消耗引起的排放占到96.95%,主要集中在建筑工程、内部装修工程和外部装饰工程3个环节。运行管理阶段电力消耗、热力消耗和污水处理过程的排放量占到总量的98.69%。根据核算及分析结果提出了案例园区在建设和运行管理阶段实现温室气体减排的建议。     

Thermodynamic rarity of electrical and electronic waste: Assessment and policy implications for critical materials

The strategic relevance of extracting raw materials from waste from electrical and electronic equipment (WEEE) in the EU is increasing due to value chain risks caused by geopolitical instability, accessibility of specific minerals, and decreasing reserves due to growing extraction rates. This article examines the quantities of so-called critical raw materials (CRMs) originating within WEEE streams from a depletion perspective. Presently, current recycling targets are based solely on mass collection and recycling rates. We examine the potential limitations of this approach using an exergy-based indicator named thermodynamic rarity. This indicator represents the exergy costs needed for producing materials from the bare rock to market. The case of Italy is used to explore the application of the indicator at the macro (national) and micro (company) level for the product categories “small electronics” and “screens and monitors.” Our estimations show significant differences between the mass and rarity of materials within Italian WEEE streams. While iron accounts for more than 70% of the weight of the product categories analyzed, it accounts for less than 15% of the rarity. Similarly, several CRMs with a small mass have a higher rarity value, for example, tungsten with less than 0.1% of the mass and over 6% of the rarity. The policy context is reflected upon, where it is argued that thermodynamic rarity can provide novel insights to support end-of-life WEEE decision-making processes, for example, target development and recycling standards setting to help prioritize material monitoring and recovery options.     

能源重化工工业园环境系统动力学仿真与调控

以锦界工业园环境系统为对象,在系统结构分析基础上,构建其系统动力学模型,并确定生产性投资比例、科技投资比例、环保投资比例、污水处理投资率、废气处理投资率、固废处理投资率为调控参数进行仿真。结果表明,当生产性投资比例由0.14提高到0.16,科技投资比例由0.02提高到0.04,环保投资比例由0.04提高到0.08,污水处理投资率由0.4下调为0.36,废气处理投资率由0.2提高到0.34,固废处理投资率由0.4下调为0.3时,园区年均工业总产值增长率达到21%,环境相对污染度年均降幅为8.1%,人口年增长率为4.7%,系统达到相对最优状态。因此,锦界工业园在环境管理中应采取以下措施:一是合理的调整生产、科技和环保的投资比例,适当降低生产性投资比例,增加科技投资和环保投资比例;二是合理的调整污水、废气和固废处理的投资比例,加强三废处理的基础设施建设,为构建完整的三废回收和处理系统奠定基础。