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Worldwide pulp and paper industry is recognized as a serious threat due to the discharge of various toxic contents present in its effluent to the surrounding environment. To combat this challenge, the role of oleaginous yeast to utilize the pulp and paper industry effluent for the integrated toxic contents removal and sustainable biodiesel production were undertaken. Oleaginous yeast Rhodosporidium kratochvilovae HIMPA1 was used as a model organism for its unique ability to utilize pulp and paper industry effluent as a culture medium and accumulate high quantity of triacylglycerol or neutral lipids as large size lipid droplets of 4.56 ± 0.24 μm within its cellular compartment. The maximum cell dry weight (13.87 g/L) with total lipid yield of 8.56 g/L was obtained after 144 h of cultivation. Data showed significant reduction in effluent toxic components i.e. color, 89%; lignin, 94.27%; phenol, 99.60%; biochemical oxygen demand, 77.36%; total dissolved solids, 84.59%; and chemical oxygen demand, 94.22%. Fatty acid methyl esters profile revealed high quantity of long chain monounsaturated fatty acids (45.43%) and polyunsaturated fatty acids (15.91%) that improves biodiesel quality under low temperature condition in terms of low cold filter plugging point along with good oxidative stability and cetane number as per American Society for Testing and Materials D6751-02 and European Committee for Standardization - EN14214 guidelines. [ABSTRACT FROM AUTHOR]

For remote areas, small-scale local biodiesel production is particularly attractive if producers and consumers are the same. Such supply chains are labeled as bidirectional. However, little is known on how raw material supply, transportation, logistics, production and operations uncertainties impact the operational performance of such Bidirectional Biodiesel Supply Chains. This paper contributes by exploring these uncertainties in a multiple case study, directed at mobile processing of rubber seeds, in a remote area. Scientifically, the paper contributes by identifying several novel sources of uncertainty: a short-term perspective, lack of knowledge and the previously unrecognized influence of the local government. Additionally, based on these findings, an extended theoretical framework is proposed which links sources of uncertainty to operational performance. The study provides also insights for stakeholders aiming to increase local biofuel production and provides a stepping-stone to investigate adequate measures to manage the identified uncertainties. [ABSTRACT FROM AUTHOR]

Abstract The present paper aims to investigate the environmental and economic impacts of co-processing petroleum fractions with bio-based feedstocks for direct refinery integration versus the conventional drop-in integration of biofuels with compatible transportation fuels. Three different pathways of market diesel (commercial diesel fuel from a typical fuel station in Greece) production with 10% v/v biocontent (biomass feed) were explored by variant biomass utilization with fossil counter parts (diesel fuel). The first case study depicts the current market diesel production process via blending petroleum fractions with FAME (Fatty Acids Methyl Esters) biodiesel. The second case study involves the production of market diesel from blending petroleum fractions with hydrotreated residual lipids (Waste Cooking Oil, WCO), while the third case study explores the alternative approach of co-processing petroleum fractions with WCO. In all cases, the market diesel production chain was based on the hydrotreating process simulated using Aspen Plus. The results have shown that the most beneficial case, by environmental and economic viewpoint, for market diesel production with 10% v/v biocontent in the Greek market is co-processing of petroleum fractions with WCO. This approach accounts for a reduced production cost (751 €/m3) and environmentally friendly profile (243 kgCO 2 -eq/m3) compared with the other two case studies. Additionally co-processing of residual biomass with petroleum fractions utilizes existing infrastructure towards the production of sustainable fuels, rendering this pathway more attractive form a CAPEX point of view. Graphical abstract Image 1 Highlights • Three production technologies of 10% bio-content diesel are evaluated. • Hybrid diesel reduces GHG emissions by ∼24% compared to current market diesel. • Renewable fuels are economically attractive for waste oil prices below 725 €/m3. • Co-processing reduces the production cost of current market diesel by 6%. [ABSTRACT FROM AUTHOR]

Abstract Due to the European favorable policy, the process to convert Used Cooking Oil (UCO) into biodiesel has resulted in a rapid increase over the last years. However, the manufacture of biodiesel can be hazardous if suitable precautions are not taken, as it involves the storage, handling and use of several hazardous substances. Although the rise in the number of biodiesel process plants and new operators has resulted in a number of incidents resulting in loss of life and property, publications concern the risks regarding the production of UCO based biodiesel are limited. By taking into account the high rise of the biodiesel industry and UCO collection it is essential to develop an operational risk management tool. The scope of this paper is: (i) the clarification of the importance of safety during the production (life cycle) of UCO based biodiesel; (ii) the identification of probable hazards incorporated to the overall production process of UCO based biodiesel; and (iii) the assessment of these hazards by stakeholders. In this way, there will be available data which allow to check the performance and to avoid mishap recurrence, by identifying the converse incidents which are more likely to occur. Highlights • Hazards in the UCO-to-biodiesel industry were categorized and assessed. • The highest identified hazards were related to the storage and use of methanol in the biodiesel plant. • The major type of accidents at biodiesel facilities recognized to be fires and explosions. [ABSTRACT FROM AUTHOR]

Abstract The objective of this study is to identify, through motivating, inhibiting and facilitating factors, responses to institutional pressures on the relationship between biodiesel plants and family farming cooperatives via the Social Fuel Seal (SFS) in the South region of Brazil. This region is characterized by well-endowed family farming cooperatives. This paper adopts as theoretical lens the institutional theory. It is based on case studies involving qualitative research drawing results from four biodiesel plants with SFS certification and eight family farming cooperatives. The results indicate that the institutional biodiesel framework influenced the SFS-based relationships. This coercion mechanism led the plants to comply with the promotion of family farming via cooperatives. The plants seek legal legitimacy and opt to accept institutional pressures, primarily due to the guaranteed sale of all biodiesel produced via government sponsored auctions. Cooperatives are attracted by the receipt of the social bonus, seen as a prime motivating factor, which can be interpreted as an informal coercive pressure. Considering the context in which the plants and cooperatives are inserted, the SFS promoted changes in the sale of raw materials. It was also found that cooperatives facilitating factors are inversely related with plants inhibiting factors. Highlights • The government acts as an inducer and regulator of the biodiesel supply chain. • SFS based institutional interventions curb market dynamics. • In environments controlled by coercive pressures, companies adapt through specific incentives. [ABSTRACT FROM AUTHOR]

Abstract Moringa oleifera (M. oleifera) is a fast-growing, drought tolerant tree which has recently been identified as one of the prospective sources of biodiesel and one of the plants which can play a prominent role in the fight against desertification. In order to accelerate the commercialization of M. oleifera -based biodiesel, this paper develops a two-stage optimization model for the design of an efficient M. oleifera biomass to biodiesel supply chain. In the first stage, a common weight data envelopment analysis (CWDEA) model is utilized to rank locations threatened by desertification and land degradation. The locations with high vulnerability are introduced as candidate locations into the second stage in which a mixed-integer linear programming model is proposed to systematically design and optimize the entire supply chain and determine the optimal strategic and tactical supply chain decisions. To illustrate the application of the developed model, a case study in semi-arid lands of Iran is conducted. The results indicate that M. oleifera biodiesel production is not competitive with petroleum-based fuels but there is considerable room for cost reduction through improvement in M. oleifera productivity and oil conversion rate. Moreover, the areas at risk of desertification can be reclaimed by an increase of only 5% in the total supply chain cost. Highlights • A supply chain model is developed for biodiesel production from Moringa oleifera. • The proposed model is able to combat desertification with a small increase in the total cost. • The total supply chain cost is dominated by the cost of biorefineries and extraction plants. • The supply chain moves from a centralized to a distributed structure over the planning horizon. [ABSTRACT FROM AUTHOR]

This paper compares the water footprint profiles of four feedstocks used for biodiesel production: palm, soya, rapeseed and waste cooking oil (WCO). The profiles include: (a) a water scarcity footprint related to freshwater consumption impacts and (b) a water quality degradation footprint related to freshwater degradation impacts. The water scarcity footprint was assessed using two impact assessment methods: one based on water stress indices (WSIs) and the other on the available water remaining (AWARE) indicator. The water degradation footprint was assessed considering the environmental mechanisms covered by the impact categories of eutrophication, aquatic acidification, human toxicity and freshwater ecotoxicity. The water scarcity profiles ranged from 0.002 to 2.11 world m 3 eq kg −1 oil (WSI method) and from 0.008 to 133.57 world m 3 eq kg −1 oil (AWARE method). Both methods showed that the cultivation stage assumes the primary role in the water scarcity footprint results and identified the same systems with higher water scarcity footprints. However, for the oil systems with closer results, the rank order given by each method is different due to the characterization factors of each method. Nevertheless, the results obtained with the AWARE method give more comprehensive water scarcity footprint results than those obtained when applying WSIs because AWARE considers the aquatic ecosystem water demand. The water degradation footprint of virgin oils is mainly caused by fertilizers and pesticides used in cultivation. WCO systems present lower impacts for all impact categories with the exception of human toxicity-cancer. The choice of locations with lower water scarcity to produce oil crops can be a determinant in the calculation of lower impacts. Moreover, optimizing fertilization schemes or choosing climatic conditions that require less fertilizers, pesticides and water consumption can reduce the impacts of the water footprint profile of vegetable oils. [ABSTRACT FROM AUTHOR]

The growing concern over the dependency on fossil fuel has prompted the cost of energy supply to the high extent. Widespread application of fossil fuel in transportation and electricity generation has steadily declined the fossil fuel supply along with the provoked environmental pollution. Strict environmental concern, depletion and price hike of fossil fuel has driven scientific study for the search of alternative fuels. To address the difficulties of fossil fuel, alternative fuels could be a fruitful substitute for global emission reduction. Where biodiesel makes itself as one of the best available resources due to its vast applicability in diesel engine. Among other biodiesels, palm biodiesel has proved itself as a most dominating biofuel due to its highest contribution worldwide (35%), minimum price (660 USD/ton), maximum oil content (5000 kg oil/ha), and production yield (4.2 MT/ha). The worldwide palm oil market progressively growing and it is expected to reach a market value of US$92.84 billion in 2021. The aim of this paper is to address different aspects of palm biodiesel for the potential solution of future renewable fuel. This paper describes a detailed review on palm biodiesel as a notable alternative in respect to the economy, environment, and efficiency. A thorough production process, properties, advantages, disadvantages, and the global economy of palm biodiesel are discussed. This article also deals with the sustainability, social, and environmental impact of leading palm oil producers like Malaysia, Indonesia, and Thailand. In this article, diesel engine combustion using palm biodiesel and its effect on engine efficiency and environmental pollution (due to engine emissions) are also reviewed. The scope of the present study relies on the brief description of the development and challenges of palm biodiesel feedstock for the continuation in the coming future. Image 1 • Biodiesel as an alternative fuel and its global impacts. • Worldwide economic and social aspects of palm oil biodiesel. • Effects of different operating parameters on palm biodiesel production process. • Current trends of Palm biodiesel: Malaysian, Indonesian and Thailand perspective. • Different metallic/non-metallic additives on engine combustion, performance and emissions. [ABSTRACT FROM AUTHOR]

The booming of biodiesel production has led to the increase in biodiesel by-product or crude glycerol, which has been proven to be a potential raw material or feedstock to be adopted in green technologies for conversion into valuable products. Its versatility and sustainable nature make it a good candidate to replace petroleum based products. Efforts have been carried out to utilize crude glycerol into biohydrogen via glycerol fermentation. Biotransformation of crude glycerol is promising because the capital investment and operation is cheaper, and it can help in reducing waste thus making the process itself a clean process. This paper reviews on the latest development of biohydrogen production from biodiesel by-product with the main focus on glycerol fermentation. It also sheds light on the challenges, effects of operating parameters on biohydrogen yield, the microorganisms and their pathways, and the possible technologies that can be derived from this bioconversion of biodiesel waste. [ABSTRACT FROM AUTHOR]

The aim of the paper is to analyse biodiesel market acceptance in Spain. In particular, we study the intention to use biodiesel by Spanish diesel car drivers and the factors explaining this intention. To achieve this goal, we developed a model of the intention to use biodiesel based on the Theory of Planned Behaviour but extended in two ways. The first one consists of the inclusion of two new predictors of the intention to use (environmental self-identity and biodiesel knowledge) and the second, the extension of the model to take into account the two barriers in the adoption of biodiesel in the market (potential price premium and limited availability in the petrol stations). This model has been specified as an ordered probit and estimated using data from a survey conducted in Spain. Results indicated that apart from the attitudes towards biodiesel use, the most important factors explaining the intention to use biodiesel are the biodiesel knowledge and the environmental self-identity, in other words, the new predictors in the Theory of Planned Behaviour model. In addition, the effects of all the factors (attitudes, subjective norms, perceived behavioural control, biodiesel knowledge, environmental self-identity and socio-demographic characteristics) on the intention to use were different, depending on the price and the availability of the biodiesel in the market. Thus, we can conclude that to analyse the intention to use biodiesel, different price and availability scenarios should be taken into account. Empirical results indicated that to increase biodiesel use, the best option is to increase biodiesel knowledge and environmental self-identity. [ABSTRACT FROM AUTHOR]

This paper examines the potential of utilising dissolved air flotation sludge obtained from a local meat processing plant in New Zealand as a viable biodiesel feedstock. In this study the dissolved air flotation sludge was characterised and the physicochemical properties of the lipid extract were assessed. The fatty acids present in the lipid extract were explored as a precursor to the estimation of the fuel properties of the biodiesel produced. This study has demonstrated the insufficiency of the traditional alkaline catalysed transesterification biodiesel pathway when meat processing dissolved air flotation sludge is utilised as a biodiesel feedstock. Therefore an alternative integrated hydrolysis and esterification production process has been proposed. The fluid behaviour (Newtonian or non-Newtonian) of the lipid extract was investigated to facilitate an improved understanding of the nature and physical state of the extract. Using a thermodynamic model and experimental data from the literature, the fuel properties, viscosity, density, oxidative stability, heating value and cetane number, of the produced biodiesel as a function of the fatty acid methyl ester profile were estimated. These properties satisfy the existing biodiesel fuel property standards. A preliminary economic assessment of the biodiesel production process using the dissolved air flotation sludge as the feedstock was also conducted. The initial favourable financial results provided a compelling basis for further investigations into the techno-economic feasibility of the production process. The poor cold flow properties of the produced biodiesel were however identified as significant considerations that may limit the utilisation of the dissolved air flotation sludge as a biodiesel feedstock in a temperate climate region like New Zealand. Possible solutions to this problem were initially discussed. In addition, health and safety concerns with the utilisation of this feedstock were identified. Approaches to limit the harmful effects of possible pathogenic content and unpleasant smell of this feedstock were also explored. [ABSTRACT FROM AUTHOR]

In this paper, we develop a decisional framework and a mathematical model for the sustainable design of biodiesel supply chain networks (BSCND). We consider a broad group of sustainable aims, i.e. standard economic goals (revenue and logistics costs of BSCND), environmental issues based on a biodiesel production life cycle assessment (LCA), and the social incidental aspects (e.g. crime control, political stability, and community attitude, among others). The framework begins with a simulation of the biodiesel production system, feeding later, with suitable input parameters and suitable solutions, and a macro-location model designed to establish the regional positioning of biofuel conversion plants. Optimal regions are used as initial feasible solution space for the proposed micro-location model. In this part of the framework, we introduce an adaptation of Extended Goal Programming to rank the best municipalities (definitive locations) emphasizing the social aspects under consideration. The framework application is set up in the following Colombian context: first generation biodiesel production from palm oil feedstock. Our computational results indicate that the Colombian city of Rionegro (in the Santader region) is the most sustainable location for a new biodiesel plant. [ABSTRACT FROM AUTHOR]

Sustainability of vegetable oil-based biodiesel has been a controversial issue since its invention as an alternative to conventional diesel. In this study, the Inclusive Impact Index (Triple I) is applied to evaluate the trade-off between advantages and disadvantages of the biodiesel system. Triple I is a single quantitative index for sustainability assessment, which is based on ecological footprint (EF), biocapacity (BC), ecological risk (ER), human risk (HR), cost (C) and benefit (B) under the life cycle (LC) approach. Due to the lack of appropriate guidelines for calculation, the application of Triple I is varied and limited. With respect to contribution to sustainability assessment of renewable energy for transportation, this study aims to propose a methodical estimation of Triple I by integrating its current principles within the Life Cycle Sustainability Assessment (LCSA) framework. The entire study is presented in two parts: Part I identifies and describes the methodological framework of the Triple I - LCSA integration, whilst Part II involves assumed exemplifications on the application of the Triple I framework attached with the case study of an inedible vegetable oil-based biodiesel system in Ha Long Bay, Vietnam. In the first part, an integration framework of the Triple I and LCSA was developed. Accordingly, human health impacts (DALY person −1 ) and ecosystem quality impacts (PDF m −2 year −1 ) from IMPACT 2002+ and Lethal/Effective Concentration (LC/EC) (under ecotoxicity assessment) are adopted as HR and ER in Triple I, respectively. Life cycle-based EF and life cycle costing are used for EF and C and B, respectively. Under the newly developed framework, ecosystem impacts and human health impacts are firstly converted to a monetary value, then to global hectares in line with cost and benefit values. Following the success developed in the Triple I framework, this work introduces to the sustainable assessment community, especially the transportation sector, a convenient and easy-to-apply quantitative index. Furthermore, this paper also summarizes several state-of-art life cycle assessment techniques and provides brief information about biodiesel life cycle inventories and some potential impacts of the system. [ABSTRACT FROM AUTHOR]

The paper describes the reactions and separations conditions for the transesterification of rapeseed oil by butanol under potassium hydroxide as a catalyst. The product is a mixture of butyl esters of higher fatty acids, which can be used as fuel (biodiesel) for combustion engines. The effect of the chosen reaction conditions (independent variables: the reaction temperature and time, the amount of catalyst, the molar ratio of butanol to oil and the method of oil addition to butanol) on the butanolysis process was studied. The measured data was analysed by multi-linear regression and the statistical models describe the dependency of glycerides (dependent variables) on the independent variables. The transesterification was stopped by neutralization of the catalyst with both a strong and weak acid been added to whole reaction mixture. The advantage of strong acid is a very fast separation and a zero content of potassium and free glycerol, nevertheless a high acid number (1.7–4.5 mg kg −1 ). In the case of weak acid (gas carbon dioxide), the acid number is less than 0.5 mg kg −1 , but the separation takes longer. Moreover, the separation was sped up by the addition of a small amount of water to the reaction mixture after the reaction and removal of butanol. This way also decreased the content of potassium (10 times) and free glycerol (4 times) in the ester phase compare to the separation without water. Moreover, the relationship between the flashpoint and the content of butanol in butyl ester was described, which enables the determination only the butanol content and the calculation of the flashpoint or vice-versa. [ABSTRACT FROM AUTHOR]

The emerging industry of biodiesel obtained from ethanol and vegetable oil, presents a number of difficulties in the purification step of the obtained esters. Current processes use large amounts of water to remove the by-product of the transesterification reaction. This paper presents an alternative to the washing process of biodiesel, which involves the use of ultrafiltration membranes resistant to solvents and alkalis. For that, two lab-made hydrophobic polymeric membranes were prepared from poly(vinylidene fluoride) and poly(sulfone) as main materials. The synthesized membranes were used to reduce glycerol content of biodiesel solutions obtained from semi-refined soybean oil and ethanol, catalyzed by sodium hydroxide. The poly(vinylidene fluoride) membrane reached a glycerol rejection up to 67% (at 30 °C and 5 bar) from a biodiesel sample with 0.5 wt % of water added. Under the same operation conditions, the poly(sulfone) membrane showed a lower separation performance, with glycerol rejection of 48%. Moreover, stability tests demonstrated that poly(vinylidene fluoride) membrane was more stable to solvents, alkalis and temperature, compared to the poly(sulfone) membrane. A remarkable flux recovery after more than 45 cycles of biodiesel permeation (≈105 hs) was verified in poly(vinylidene fluoride) membrane, indicative of the high stability and low fouling of the membrane. [ABSTRACT FROM AUTHOR]

Combustion of fossil fuels in the transport sector represents the second largest source of greenhouse gas emissions. For this reason, governments are fostering diversification of energy sources by creating a set of governmental environmental policies and initiatives. In this context, biofuels are expected to represent a substantial part of source diversification, but it is necessary to assess the sustainability of their market to explore its effect on economical, technological, social, political and environmental dimensions. This research presents a dynamic simulation modelling of the Colombian biodiesel market and analyzes the policy support instruments for creating and managing it. A system dynamics based model is proposed to enable decision-makers to understand the influences between the different variables that describe the system and the impact of the biodiesel government policy in Colombia. The primary focus of this paper is to establish the characteristics of each sustainability dimension for the case of study and apply the system dynamics methodology with different types of validation. Finally, the Colombian market status and a sensitivity analysis are developed. The results show that in order to support the development of this sector, it is necessary to diversify the raw materials for the production of biodiesel in the medium term, which means raw materials without competence for the primary rainforest or competition with food productive lands. [ABSTRACT FROM AUTHOR]

Globally, the demand for energy is increasing, and the transportation sector is a major consumer of energy. There has been a momentum and a mandate to promote the use of biofuels. Although biofuel usage has been analysed extensively from the technological viewpoint, very few researchers have studied biofuel implementation and the supply chain. Biodiesel is being considered as an alternative fuel for railway transportation, which poses some challenges given the structural constraints of the industry. As has been argued, for the successful implementation and adoption of biodiesel in the railway sector, a tailor-made country-specific supply chain should be designed. The paper discusses how geographically diverse demand and common technological usage points complicate the decision to make or buy in the context of railway transportation. Furthermore, the biodiesel and diesel supply chains are compared, risks of a biodiesel supply chain are identified, and implementable strategies are suggested. Indian Railways is a bulk consumer of fuel, and as a public sector focal firm, it should take the lead in sustainable transportation solutions in view of energy security requirements. This study is unique because it deals with a biodiesel supply chain in a public sector transport organization in an emerging economy. [ABSTRACT FROM AUTHOR]

This paper evaluates the environmental and economic performance of a biodiesel plant by using the data envelopment analysis framework considering two outputs (biodiesel and glycerin as a by-product of the biodiesel) and five inputs (waste cooking oil, methanol (MeOH), potassium hydroxide (KOH), power consumption used for operating the biodiesel plant, and truck diesel fuel used for the collection of waste cooking oil). From the results estimated using the time series database on monthly biodiesel production during August 2010 to March 2013, we found that there were many technologically inefficient production activities during the study period. We also demonstrate that a reduction of input costs for the study period of about 5% is possible and life-cycle CO 2 emissions associated with biodiesel productions can be further reduced, while the “first best” production activity in both cases of including and excluding external costs for life-cycle CO 2 emissions associated with biodiesel productions occurred in February 2013 and the minimum unit production cost was attained in this month. [ABSTRACT FROM AUTHOR]

The paper analyzes biodiesel chains of rapeseed ( Brassica napus ) and carinata ( Brassica carinata ) cultivated in Central and Southern Italy, assessing the impact on Global Warming Potential by means of the Life Cycle Assessment methodology. The production chains differed in use of the oilcake, as animal feed for rapeseed and as biofumigant for B. carinata . The allocation of emissions across co-products was first calculated on the basis of their energy content according to the criterion proposed by European Commission for biofuel production. The resulting impacts were then compared to those obtained through the substitution approach (system expansion method), which considers emissions that are saved by replacing the equivalent conventional product with co-product bio-based materials i.e. soybean meals, nematicidal fumigants, fertilizers and glycerol. The results showed that this method is sensitive to pointing out the importance of the valorization of co-products to the sustainability of bioenergy supply chain. Among the different options taken into consideration, in the case of the B. carinata biodiesel chain, the substitution of conventional fumigants and fertilizers with biofumigants and amendments is able to determine a global net saving of 134 g CO 2 eq per MJ of biodiesel, reversing the sustainability assessment obtained through the energy allocation method. Overall, the results suggest that, when planning future biorefineries, environmental assessment should take the substitution approach into account in order for valorization of co-products and diversification of processes to be rewarded. [ABSTRACT FROM AUTHOR]

Decarbonisation of transport has become central to European Union policy. Biofuels are expected to represent a substantial part of the overall strategy towards diversifying Europe's energy supplies and curbing greenhouse gas emissions in a cost-effective way. This research deals with the dynamic simulation modeling of a biodiesel market as a part of transportation fuel market and analyses of various policy support instruments on increasing the proportion of biofuel in total transport fuel demand. The study is carried out for Latvia's road transport sector. After it had experienced generous financial support from the government allowing the industry to develop, support was abruptly stopped creating stagnation in both biodiesel supply and demand. This threatened the national transport policy goals. The goal of this research is to find the most effective policy strategies for achieving the national transport policy goals by applying system dynamics modeling to the current market conditions of transport fuels.. Specifically, the primary focus of this paper is an attempt to gain insight into the long-term dynamic behavior of the biodiesel market in Latvia. The principal policy tools and mechanisms implemented can be summarized as: i) state subsidies at different levels and stages (i.e. the biodiesel production sector, the agricultural sector, and the end consumer sectors), ii) increasing the excise taxes on fossil fuels, iii) increasing the share of the biodiesel in the transportation fuel blend. The results obtained from model simulations confirm that promoting biofuel acceptance among end-users is the primary key issue. [ABSTRACT FROM AUTHOR]

Nowadays, the use of edible oils with elevate purity in the biodiesel production represents around 70% of the chain of feedstocks applied in the process by the main producing countries at world level. This occurs due, mainly, to reaction limitations of the traditional alkaline route employed industrially. Bypassing drawbacks of the chemical process, enzymatic technique is an effective alternative for the biodiesel synthesis. In this sense, this paper reports results to semi-continuous production of biodiesel on pilot scale, from waste cooking oil, via hydroesterification mediated by different commercial lipases in liquid formulation: Eversa® Transform and its novel thermostable successor Eversa® Transform 2.0. Data for yields, residual acidity, productivities, biocatalysts performance, kinetics and economic analysis are presented in this comprehensive research. Using the best reaction conditions found (40 °C, 0.7 wt% of Eversa® Transform 2.0, 4.0 wt% of water, methanol to oil molar ratio of 6.3:1 and 8 h at a two-step reaction system), 96.2% of FAME yield was achieved. A pseudo-first order model presented a good fit of the experimental data, where a k App of 0.373∙h−1 was obtained for the process with the best performance. Moreover, for this process, an economic analysis indicated the feasibility of the system through a positive net return and operating cost of US$ 0.50 kg−1 of biofuel. This information served as foundation to conclude that enzymatic hydroesterification catalyzed by liquid lipases has the necessary tools to be implemented on industrial biodiesel production. Image 1 [ABSTRACT FROM AUTHOR]

Consequent to the escalations in global energy consumption, the biomass-to-fuel processes are increasingly becoming important areas to the energy industry and policy makers. In this perspective, the valorization of oils and fats via transesterification/esterification reaction is an attractive method for producing biodiesel with qualities suitable for the diesel engines. Owing to its numerous advantages, the global consumption of biodiesel had increased from 0.25 billion gallons in 2006 to ∼2.0 billion gallons in 2018, and the trend has also been projected to be linear in the future years. Although several catalytic systems have been evaluated for its production, the recent interest indicated a shift to industrial wastes as another approach for escalating the process eco-scientific efficiencies. The review therefore comprehensively explored the role of utilizing red mud, tailings, slags, other geothermal wastes, carbide slag (CS) and fly-ash-derived zeolites as catalytic systems for biodiesel production. The influence of waste compositions, modifications and reaction/calcination conditions in achieving optimum activity were discussed. The paper further documented progress in terms of process mechanism, active sites identification and strategies adopted for promoting catalyst stability, recovery and reuse. Key perspective areas for further research studies were carefully identified and discussed. Image 1 • Biodiesel consumption has increased tremendously over the years (2006–2018). • Oxides, heteropoly acids and zeolites were the catalysts prioritized before. • Wastes such as red mud, slags, tailings, fly ash-zeolites are good replacements. • Detail discussion on the role of these industrial wastes provided herein. • Further research areas were provided for eco-scientific process design. [ABSTRACT FROM AUTHOR]

Over reliance on fossil fuels to meet the ever increasing energy demands has adversely affected the economy and environment of Pakistan. The transportation sector is the major consumer of these imported petroleum products. Among these petroleum products, high speed diesel and gasoline are the most consumed. Bio-fuels, produced from indigenous biomass, can surmount the twofold problem of deteriorating environment and sustainable supply of energy resource. As an agricultural country, Pakistan prodigiously produces biomass (e.g. animal dung, molasses and bagasse) which can replace natural gas, gasoline and electricity conventionally produced from fossil fuels. However, an alternative to high speed diesel has not been identified yet. This review paper is focused on developing a strategy for identifying potential biodiesel feed-stocks suitable for Pakistan and their contribution towards "the solution" of sustainable energy and environment. The selection parameters for feedstock, land, irrigation, oil yield, composition and maturation duration are discussed in detail. Based on agro-climatic conditions of the Pakistan, castor and jatropha cultivated on water scarce lands are lucrative feed stocks for bio-diesel. Moreover, by-products of both these feed stocks like seed cake and glycerine are explored for production of gaseous fuel such as bio-gas or hydrogen, electricity generation and animal meal production which can render biodiesel economically viable. An integrated approach for biodiesel production associated with by-products utilization has been proposed. Image 10634 • Latest trends of fossil and renewable energy mix in Pakistan has been discussed. • Availability of land in accordance with agro-climatic conditions is evaluated. • Crop and oil yields are significantly affected by soil fertility and rain per year. • Co-cultivation with castor for short term and jatropha for longer term is suggested. • A strategy integrating biodiesel production and by-products utilization is proposed. [ABSTRACT FROM AUTHOR]