Research and economic perspectives on an integrated biorefinery approach for the simultaneous production of polyhydroxyalkanoates and biohydrogen.

Alarming environmental impacts have been resulted across the globe due to the recovery and consumption of fossil fuels. The elevated global carbon footprint has paved the way to an alternative to combat the prevalent pollution. On the other hand, the fossil-based plastics produced from the byproducts of petroleum remain intact in the environment leading to pollution. Fossil abated bioproducts are in high demand due to the increase in pollution. This call to utilize feedstock for simultaneous production of biologically useful products through carbon capture utilisation where the leftover carbon-rich substrate is converted into usable chemicals like bioplastics, methanol, urea and various other industrially essential components. The present review extensively focuses on the research and economic perspectives of an integrated biorefinery and addresses technical breaches, bottlenecks, and efficient strategies for the simultaneous production of biohydrogen and polyhydroxyalkanoates.

Modelling welfare estimates in discrete choice experiments for seaweed-based renewable energy.

We explore what researchers can gain or lose by using three widely used models for the analysis of discrete choice experiment data-the random parameter logit (RPL) with correlated parameters, the RPL with uncorrelated parameters and the hybrid choice model. Specifically, we analyze three data sets focused on measuring preferences to support a renewable energy programme to grow seaweed for biogas production. In spite of the fact that all three models can converge to very similar median WTP values, they cannot be used indistinguishably. Each model is based on different assumptions, which should be tested before their use. The fact that standard sample sizes usually applied in environmental valuation are generally unable to capture the outcome differences between the models cannot be used as a justification for their indistinct application.

Biofuel production from Macroalgae: present scenario and future scope.

The current fossil fuel reserves are not sufficient to meet the increasing demand and very soon will become exhausted. Pollution, global warming, and inflated oil prices have led the quest for renewable energy sources. Macroalgae (green, brown, and red marine seaweed) is gaining popularity as a viable and promising renewable source for biofuels production. Numerous researches have been conducted to access the potential of macroalgae for generating diverse bioproducts such as biofuels. The existence of components such as carbohydrates and lipids, and the lack or deficiency of lignin, create macroalgae an enviable feedstock for biofuels generation. This review briefly covers the potential macroalgal species promoting the production of biofuels and their cultivation methods. It also illustrates the biofuel generation pathway and its efficiency along with the recent techniques to accelerate the product yield. In addition, the current analysis focuses on a cost-effective sustainable generation of biofuel along with commercialization and scaleup.

Techno-economic assessment of bioethanol production from lignocellulose by consortium-based consolidated bioprocessing at industrial scale.

Lignocellulose-based biofuels are of major importance to mitigate the impact of international traffic and transport on climate change while sustaining agricultural land for food supply. Highly integrated systems like consolidated bioprocessing (CBP), where enzyme production, enzymatic hydrolysis and fermentation of the released sugars are carried out in one reactor, offer the highest potential to save costs and to make lignocellulose-based biofuels economically competitive. The work described here showed that CBP based on a microbial consortium operated at full-scale (2000 t/d) saves up to 27.5 % of the total ethanol production costs compared to conventional ethanol production from lignocellulose in individual process steps. The cost savings are mainly achieved through lower CAPEX due to less apparatus requirements because of the integrated process, as well as through lower OPEX since no glucose is needed for enzyme production. A comparison with literature estimations of cost savings of CBP based on genetically modified microorganisms results in approximately the same range. As a result of a detailed sensitivity analysis, scale and yield were identified as the main cost-pushers from a process point of view, whereas the price level of the plant location has the highest impact on the investment conditions. In the EU, CBP yields enough margin for profitable production and the possibility to decentralize biomass valorization, whereas in the world's largest ethanol market, the U.S, profitable production of lignocellulosic ethanol can only be achieved by CBP combined with other cost saving techniques, such as utilization of cost-free waste feedstocks, since ethanol has undergone a considerable price slump.

Microbial production of advanced biofuels.

Concerns over climate change have necessitated a rethinking of our transportation infrastructure. One possible alternative to carbon-polluting fossil fuels is biofuels produced by engineered microorganisms that use a renewable carbon source. Two biofuels, ethanol and biodiesel, have made inroads in displacing petroleum-based fuels, but their uptake has been limited by the amounts that can be used in conventional engines and by their cost. Advanced biofuels that mimic petroleum-based fuels are not limited by the amounts that can be used in existing transportation infrastructure but have had limited uptake due to costs. In this Review, we discuss engineering metabolic pathways to produce advanced biofuels, challenges with substrate and product toxicity with regard to host microorganisms and methods to engineer tolerance, and the use of functional genomics and machine learning approaches to produce advanced biofuels and prospects for reducing their costs.

Jatropha curcas, a Novel Crop for Developing the Marginal Lands.

Jatropha curcas L. has more attention from researchers and policymakers as an inexpensive source for produce biofuel to reduce environmental pollution by fossil fuel in the next decades without competing for lands and freshwater currently used for food production. Jatropha is a perennial deciduous, succulent oilseed shrub, belonging to family Euphorbiaceae. It is native to Central and South America. It is a multipurpose shrub, each part of the plant can be used for various purposes, Jatropha produces flowers throughout the year and enables multiple harvests, while, in arid and semi-arid regions it is harvesting twice time per year.Jatropha is a drought-tolerant plant that could be growing under malnutrition conditions, and in different climatic conditions; therefore, it is proper plant for developing marginal lands and rural areas.Due to the growing demand for biofuel, jatropha cultivation has received more attention to providing seeds. While, there are various aspects of using jatropha include use as a traditional medicine for treating skin ailments, as a hedge for protecting other crops, to reduce soil degradation, combating desertification, and deforestation, also, jatropha cultivation protects the environment through using wastewater in irrigation and reduce sequester carbon dioxide.Conventional propagation of Jatropha propagated by seeds or stem cutting which is a more satisfactory technique to produce high-yielding seedlings, while, tissue culture method used in propagation but on small scale.Jatropha curcas L. contains mixtures of numerous active substances in all parts of the plant, which are used as biopesticides, larvicides, fungicide, and nematicide; also extracts are used as pesticides for whiteflies and termites.Jatropha crude oil is used for industrial purposes like manufacturing candles, soaps, varnishes, and as a lubricant; also press seedcake is used to produce biogas and organic fertilizers. Jatropha propagated by seeds or stem cutting which is more applicable techniques to produce high-yielding seedlings, also, tissue culture method used in propagation but on small scale for scientific work.

Economics of Biofuel Production: A Case of Sorghum and Pearl Millet in India.

Reduction of fossil fuels at an alarming rate has attracted increasing attention to blending biofuels worldwide. India's energy demand is expected to grow at an annual rate of 4-5 times over the next couple of decades. With self-sufficiency levels in crude oil becoming a distant dream, there is growing interest to look out for alternative fuels and the biofuels are an important option for policy makers in India. In this context, this paper reviews the experiences in India in the last two decades with respect to biofuel cultivation and its impact on land use, environment, and the livelihoods of rural communities. The objective of this paper is to assess the economics of biofuel production using Sorghum and Pearl millet feedstocks in India using a Life Cycle Analysis (LCA) approach. Baseline study was conducted during the year 2013 in the Madhya Pradesh state of India covering five districts and 333 sample farmers to understand the farmers perception about the various issues related to the production of biofuels using Indian staple food crops Sorghum and Pearl millet. Empirical data from the multi-locational trials conducted during the years 2014-2015 and 2015-2016 in farmers' fields was used to conduct the LCA analysis. Sorghum and Pearl millet feedstocks which are rain-fed crops are considered for bioethanol production with different pretreatment methods. Net Energy Ratio (NER), Net Energy Balance (NEB), Net Carbon Balance (NCB), and % Carbon reduction were some of the key parameters used for analysis and the results are evaluated based on the environmental impacts through the Life Cycle Assessment at 5% blending. Findings reveal that, dilute alkali pretreatment process is most energy intensive due to consumption of alkali consumption. Whereas dilute acid pretreatment has higher conversion efficiency than the other pretreatment processes which is due to higher glucan and xylan conversion efficiencies.The study concludes that Sorghum feedstock is more energy intensive than Pearl millet feedstock due to higher water requirement and yield. Biofuels, either conventional or advanced, should not been couraged without a comprehensive outlook on the overall impact that will ultimately have on the society, environment, or on the countries' energy security. Efforts should be made toward encouragement of research and development in the field as well as in formulating a comprehensive and effective biofuel policy for India.

Biofuels and Sustainability.

Energy security and climate change have cascading effects on the world's burgeoning population in terms of food security, environment, and sustainability. Due to depletion of fossil fuels and undesirable changes of climatic conditions, increase in air and water pollution, mankind started exploring alternate and sustainable means of meeting growing energy needs. One of the options is to use renewable sources of fuel-biofuel. In this chapter the authors have reviewed and presented sustainability impact on production of biofuels. Authors further reviewed state-of-the-art gene editing technologies toward improvement of biofuel crops. The authors recommend a phased transition from first-generation biofuel, and an acceleration toward use of technology to drive adoption of second-generation biofuels. Key aspects of technology and application of resource management models will enable these crops to bridge the global energy demand before we can completely transition to a more sustainable biofuel economy.

Rice vinasse treatment by immobilized Synechococcus pevalekii and its effect on Dunaliella salina cultivation.

The development of new strategies in microalgal studies represents an outstanding opportunity to mitigate environmental problems coupled with biomass production at a reduced cost. Here we present a combined bioprocess for the treatment of rice vinasse using immobilized cyanobacteria Synechococcus pevalekii in alginate beads followed by the use of the treated vinasse as a culture medium for Dunaliella salina biomass production. Cyanobacterial-alginate beads showed a chlorophyll a production of 0.68 × 10-3 mg bead-1 and a total carotenoid production of 0.64 × 10-3 mg bead-1. The first step showed a decrease in nitrate (91%), total solids (29%), and ions. Addition of treated vinasse into D. salina cultivation resulted in a significant increase in cell replication of about 175% (optimized cultivation). The use of natural seawater drastically reduced the medium cost to US$4.75 per m3 and the addition of treated vinasse has the potential to reduce it even more (up to 69%). This study not only provides an insight on the use of cyanobacteria for rice vinasse treatment but also demonstrates a promising lower-cost medium for marine microalgal biomass production with biotechnological purposes.

Techno-economic analysis of ethanol production from lignocellulosic biomass-a comparison of fermentation, thermo catalytic, and chemocatalytic technologies.

Bioethanol produced from 2nd generation biomass comprising of agricultural residues and forest wastes is a viable alternate fuel. Besides fermentation and biomass gasification to syngas and its further conversion to ethanol, a direct chemocatalytic conversion of lignocellulosic biomass into ethanol is being investigated as a viable route which avoids the emission of greenhouse gases. In this work, a detailed configuration of chemocatalytic route is simulated and optimized for minimizing the cost of ethanol production. The economic feasibility of ethanol production through the chemocatalytic pathway is analyzed. The techno-economic analysis is conducted in terms of ethanol selectivity and ethanol production cost. The obtained results show that biomass feedstock and catalyst have major contributions to the production cost. The proposed route is found to be giving a lower ethanol selling price as compared to the well-researched routes of biomass fermentation to ethanol and biomass gasification followed by syngas conversion to ethanol.

Bioeconomy: Biomass and biomass-based energy supply and demand.

This paper addresses the challenges of the transition from a fossil fuel-dependent to a bio-based economy and implications related to the production of food, feed, bioenergy and other bio-based materials. The objective is to provide a comprehensive review of global biomass and biomass-based energy supplies and demand, with particular attention to the EU. Furthermore, factors related to setting priorities in the use of non-food biomass are discussed, as food security will remain the top priority. Finally, the changes in the bioenergy balance indicators in the Member States of the EU and new plant breeding technologies are analyzed. Overall, this study describes the complexity of the bio-based value chains in making decisions on how best to use biomass. The article presents a comprehensive review on global biomass and biomass based energy supplies and demand, discusses the European chemical industry perspective, analyzes the changes in the biomass based energy balance indicators in the Member States of the EU, and considers the challenges of the new plant breeding technologies.

The role of microalgae in the bioeconomy.

The bioeconomy is a new and essential paradigm for reducing our dependence on natural resources and responding to the environmental threats that the Earth is currently facing. In this regard, microalgae offer almost unlimited possibilities for developing a modern bioeconomy given their metabolic flexibility and high biomass output rates, even when produced under harsh conditions, such as when treating wastewaters or using flue gases. In this article, the microalgal contribution to important economic activities such as the production of food and feed, cosmetics and health-related compounds is reviewed. Moreover, potential contributions of microalgae to emerging sectors are discussed, as in the production of biomaterials, agriculture-related products, biofuels and provision of services such as wastewater treatment and the clean-up of industrial gases. The different microalgal production technologies have also been analyzed to identify the main bottlenecks affecting microalgal use in different applications. Finally, the major challenges facing microalgal biotechnology in enlarging its contribution to the bioeconomy are evaluated, and future trends discussed.

Valorization of byproducts from tropical fruits: Extraction methodologies, applications, environmental, and economic assessment: A review (Part 1: General overview of the byproducts, traditional biorefinery practices, and possible applications).

Tropical fruits represent one of the most important crops in the world. The continuously growing global market for the main tropical fruits is currently estimated at 84 million tons, of which approximately half is lost or wasted throughout the whole processing chain. Developing novel processes for the conversion of these byproducts into value-added products could provide a viable way to manage this waste problem, aiming at the same time to create a sustainable economic growth within a bio-economy perspective. Given the ever-increasing concern about sustainability, complete valorization through a bio-refinery approach, that is, zero waste concept, as well as the use of green techniques is therefore of utmost importance. This paper aims to report the status on the valorization of tropical fruit byproducts within a bio-refinery frame, via the application of traditional methodologies, and with specific attention to the extraction of phenolics and carotenoids as bioactive compounds. The different types of byproducts, and their content of bioactives is reviewed, with a special emphasis on the lesser-known tropical fruits. Moreover, the bioactivity of the different types of extracts and their possible application as a resource for different sectors (food, pharmaceutical, and environmental sciences) is discussed. Consequently, this review presents the concepts of tropical fruit biorefineries, and the potential applications of the isolated fractions.

Low-cost biofuel-powered autoclaving machine for use in rural health care centres.

Surgical site infections (SSIs) in developing countries have been linked to inadequate availability of sterilising equipment. Existing autoclaves are mostly unaffordable by rural healthcare practitioners, and when they managed to procure them, the electricity supply to power the autoclaves is epileptic. The solar-powered autoclave alternatives are too bulky with a very high initial cost. Hence, low-cost biofuel-powered autoclave becomes an attractive option, and this study sought to present the design, development and clinical evaluation of the device performance. With the global drive for the adoption of green energy, biofuel will not only reduce greenhouse gas emission but also provide revenue for local producers and reduce biomass associated health complications. The theoretical energy requirement for the sterilisation process was calculated. The standard pressure and temperature needed for sterilisation were tested to be 121 °C and 15 psi. The device was also clinically tested with Staphylococcus aureus bacteria obtained from the Department of Medical Microbiology and Parasitology, University of Ilorin Teaching Hospital using Brain heart Infusion Broth, MacConkey and Blood agar as cultured media. No bacteria growth was observed when the samples containing the bacteria colony were autoclaved by the designed autoclave and incubated at 37 °C for 2 d. Hence, the device met the mechanical and biological validation standards for effective sterilisation.

Accumulation of high-value bioproducts in planta can improve the economics of advanced biofuels.

Coproduction of high-value bioproducts at biorefineries is a key factor in making biofuels more cost-competitive. One strategy for generating coproducts is to directly engineer bioenergy crops to accumulate bioproducts in planta that can be fractionated and recovered at biorefineries. Here, we develop quantitative insights into the relationship between bioproduct market value and target accumulation rates by investigating a set of industrially relevant compounds already extracted from plant sources with a wide range of market prices and applications, including <$10/kg (limonene, latex, and polyhydroxybutyrate [PHB]), $10 to $100/kg (cannabidiol), and >$100/kg (artemisinin). These compounds are used to identify a range of mass fraction thresholds required to achieve net economic benefits for biorefineries and the additional amounts needed to reach a target $2.50/gal biofuel selling price, using cellulosic ethanol production as a test case. Bioproduct market prices and recovery costs determine the accumulation threshold; we find that moderate- to high-value compounds (i.e., cannabidiol and artemisinin) offer net economic benefits at accumulation rates of just 0.01% dry weight (dwt) to 0.02 dwt%. Lower-value compounds, including limonene, latex, and PHB, require at least an order-of-magnitude greater accumulation to overcome additional extraction and recovery costs (0.3 to 1.2 dwt%). We also find that a diversified approach is critical. For example, global artemisinin demand could be met with fewer than 10 biorefineries, while global demand for latex is equivalent to nearly 180 facilities. Our results provide a roadmap for future plant metabolic engineering efforts aimed at increasing the value derived from bioenergy crops.

Co-production of DHA and squalene by thraustochytrid from forest biomass.

Omega-3 fatty acids, and specifically docosahexaenoic acid (DHA), are important and essential nutrients for human health. Thraustochytrids are recognised as commercial strains for nutraceuticals production, they are group of marine oleaginous microorganisms capable of co-synthesis of DHA and other valuable carotenoids in their cellular compartment. The present study sought to optimize DHA and squalene production by the thraustochytrid Schizochytrium limacinum SR21. The highest biomass yield (0.46 g/gsubstrate) and lipid productivity (0.239 g/gsubstrate) were observed with 60 g/L of glucose, following cultivation in a bioreactor, with the DHA content to be 67.76% w/wtotal lipids. To reduce costs, cheaper feedstocks and simultaneous production of various value-added products for pharmaceutical or energy use should be attempted. To this end, we replaced pure glucose with organosolv-pretreated spruce hydrolysate and assessed the simultaneous production of DHA and squalene from S. limacinum SR21. After the 72 h of cultivation period in bioreactor, the maximum DHA content was observed to 66.72% w/wtotal lipids that was corresponded to 10.15 g/L of DHA concentration. While the highest DHA productivity was 3.38 ± 0.27 g/L/d and squalene reached a total of 933.72 ± 6.53 mg/L (16.34 ± 1.81 mg/gCDW). In summary, we show that the co-production of DHA and squalene makes S. limacinum SR21 appropriate strain for commercial-scale production of nutraceuticals.

The hydrogen gas bio-based economy and the production of renewable building block chemicals, food and energy.

The carrying capacity of the planet is being exceeded, and there is an urgent need to bring forward revolutionary approaches, particularly in terms of energy supply, carbon emissions and nitrogen inputs into the biosphere. Hydrogen gas, generated by means of renewable energy through water electrolysis, can be a platform molecule to drive the future bioeconomy and electrification in the 21st century. The potential to use hydrogen gas in microbial metabolic processes is highly versatile, and this opens a broad range of opportunities for novel biotechnological developments and applications. A first approach concerns the central role of hydrogen gas in the production of bio-based building block chemicals using the methane route, thus, bypassing the inherent low economic value of methane towards higher-value products. Second, hydrogen gas can serve as a key carbon-neutral source to produce third-generation proteins, i.e. microbial protein for food applications, whilst simultaneously enabling carbon capture and nutrient recovery, directly at their point of emission. Combining both approaches to deal with the intermittent nature of renewable energy sources maximises the ability for efficient use of renewable resources.

Lignocellulosic biomass: Hurdles and challenges in its valorization.

Lignocellulosic biomass (LCB) is globally available and sustainable feedstock containing sugar-rich platform that can be converted to biofuels and specialty products through appropriate processing. This review focuses on the efforts required for the development of sustainable and economically viable lignocellulosic biorefinery to produce carbon neutral biofuels along with the specialty chemicals. Sustainable biomass processing is a global challenge that requires the fulfillment of fundamental demands concerning economic efficiency, environmental compatibility, and social responsibility. The key technical challenges in continuous biomass supply and the biological routes for its saccharification with high yields of sugar sources have not been addressed in research programs dealing with biomass processing. Though many R&D endeavors have directed towards biomass valorization over several decades, the integrated production of biofuels and chemicals still needs optimization from both technical and economical perspectives. None of the current pretreatment methods has advantages over others since their outcomes depend on the type of feedstock, downstream process configuration, and many other factors. Consolidated bio-processing (CBP) involves the use of single or consortium of microbes to deconstruct biomass without pretreatment. The use of new genetic engineering tools for natively cellulolytic microbes would make the CBP process low cost and ecologically friendly. Issues arising with chemical characteristics and rigidity of the biomass structure can be a setback for its viability for biofuel conversion. Integration of functional genomics and system biology with synthetic biology and metabolic engineering undoubtedly led to generation of efficient microbial systems, albeit with limited commercial potential. These efficient microbial systems with new metabolic routes can be exploited for production of commodity chemicals from all the three components of biomass. This paper provides an overview of the challenges that are faced by the processes converting LCB to commodity chemicals with special reference to biofuels.

Promoting sustainability of use of biomass as energy resource: Pakistan's perspective.

Biomass is primary source of energy for household in rural communities. Developing countries are focusing on increasing utilization of indigenous energy resources for energy security and to achieve sustainable development goal. Combustion of solid biomass is the primary approach for utilizing biomass to generate electricity and heat. Sixty-eight percent of population of Pakistan is living in rural areas while 30% population is still without electricity. The traditional household appliances used for cooking and heating are less efficient, more hazardous to users, and more damaging to the environment. Low carbon energy system prerequisites access to modern energy services. This paper presents an assessment of biomass resources potential in Pakistan as renewable energy resources and reviews potentials to adopt efficient use of biomass for cooking, heating, and small decentralized electricity generation. Objective of this study is to increase the sustainability of the use of biomass as source of energy in developing countries like Pakistan by an integrating energy-efficient and modern appliances and technologies that fit into a sustainable development path. Promotion of cleaner technologies and efficient use of biomass energy constitute appropriate strategies to mitigate global climate, health risks, and help in attending the targets set by sustainable development goal (SDG) to confirm worldwide access to reliable, affordable, and modern energy services by 2030.