Sustainable Biofuel Research Articles

The Ethanologenic Bacterium Zymomonas mobilis Divides Asymmetrically and Exhibits Heterogeneity in DNA Content.

The alphaproteobacterium Zymomonas mobilis exhibits extreme ethanologenic physiology, making this species a promising biofuel producer. Numerous studies have investigated its biology relevant to industrial applications and mostly at the population level. However, the organization of single cells in this industrially important polyploid species has been largely uncharacterized. In the present study, we characterized basic cellular behavior of Z. mobilis strain Zm6 under anaerobic conditions at the single-cell level. We observed that growing Z. mobilis cells often divided at a nonmidcell position, which contributed to variant cell size at birth. However, the cell size variance was regulated by a modulation of cell cycle span, mediated by a correlation of bacterial tubulin homologue FtsZ ring accumulation with cell growth. The Z. mobilis culture also exhibited heterogeneous cellular DNA content among individual cells, which might have been caused by asynchronous replication of chromosome that was not coordinated with cell growth. Furthermore, slightly angled divisions might have resulted in temporary curvatures of attached Z. mobilis cells. Overall, the present study uncovers a novel bacterial cell organization in Z. mobilisIMPORTANCE With increasing environmental concerns about the use of fossil fuels, development of a sustainable biofuel production platform has been attracting significant public attention. Ethanologenic Z. mobilis species are endowed with an efficient ethanol fermentation capacity that surpasses, in several respects, that of baker's yeast (Saccharomyces cerevisiae), the most-used microorganism for ethanol production. For development of a Z. mobilis culture-based biorefinery, an investigation of its uncharacterized cell biology is important, because bacterial cellular organization and metabolism are closely associated with each other in a single cell compartment. In addition, the current work demonstrates that the polyploid bacterium Z. mobilis exhibits a distinctive mode of bacterial cell organization, likely reflecting its unique metabolism that does not prioritize incorporation of nutrients for cell growth. Thus, another significant result of this work is to advance our general understanding in the diversity of bacterial cell architecture.

Continuous foam flotation harvesting with enhanced drainage: Overcoming the recovery-enrichment paradox

Microalgae are promising sources of sustainable biofuels, however high harvesting and enriching costs hamper economic competitiveness. Foam flotation––a low-cost, low-energy adsorptive bubble separation technique––may bridge this gap, yet its efficiency and adoption is compromised by a perceived trade-off (based on batch operation) between two key performance indicators: recovery percentage (R%) and concentration factor (biomass enrichment ratio; CF). Previously, we challenged this ‘recovery-enrichment paradox’ under continuous operation (R% 95, CF 173), but performance fell short of expectation. Here, we present a redesign based on the concepts of process intensification, by incorporating a drainage riser, delivering concomitantly high R% (91) and CF (722), retaining low power consumption (0.052 kWh m−3 of algae culture) with high total suspended solids yield (14.6%). This compares very favorably with other dewatering/harvesting techniques, overcoming the ‘recovery-enrichment paradox’. Our significant intensification of the foam flotation process will accelerate the advent of economically sustainable microalgae derived biofuels.

Kinetic analysis and thermal degradation study on wheat straw and its biochar from vacuum pyrolysis under non-isothermal condition

The present study deals with the thermogravimetric analysis of WS and WSB at 20, 30 and 40 °C/min in inert atmospheric condition. The physicochemical characterizations of wheat straw (WS) and its biochar produced from the vacuum pyrolysis process (WSB) have been carried out using proximate and ultimate analysis technique. The kinetics and thermodynamic parameters were calculated using iso-conversional model free methods, including Kissinger-Akahira-Sunose (KAS), Starink and Flynn-Wall-Ozawa (FWO), respectively. The activation energy values for WS biomass and WS biochar are found in the range of 125–193 kJ mol−1 and 160–195 kJ mol−1 obtained from FWO, KAS and STARINK models in the conversion range of 0.1–0.8, respectively. Activation energy was found increased for different degree conversions from 0.1 to 0.8, respectively. The average values of enthalpy, entropy and Gibbs-free energy for WS are reported. The study findings for WS and WSB showed huge potential in bio-refinery industries for modelling and designing of pyrolysis reactors for sustainable bio-fuel production.

Profiling of Phenolic Compounds Composition, Morphological Traits, and Antioxidant Activity of Miscanthus sacchariflorus L. Accessions

Miscanthus sacchariflorus is a potential source of sustainable biofuel and other bioactive compounds. The high adaptive range of M. sacchariflorus may cause variation in its morphological traits and phytochemical composition. Although some metabolites have been reported from M. sacchariflorus, little is known about its phenolic compound composition and antioxidant or oxidant properties. This study evaluated the morphological traits, antioxidant properties, and phenolic compound profile of M. sacchariflorus collected from various regions of China, Korea, Japan, and Russia. The antioxidant potential of the leaf extracts of various accessions of M. sacchariflorus was estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS). An extensive study of the antioxidant activity and phenolic compounds of M. sacchariflorus obtained from different locations in four different countries could provide a comprehensive catalogue of the phytoconstituents and antioxidant properties of M. sacchariflorus accessions to consumers and nutraceutical industries. A total of 22 phenolic compounds were identified and quantified, among which p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, chlorogenic acid, vitexin, and luteolin were the most dominant phytochemical compounds detected in the majority of the accessions. The antioxidant potential (DPPH) of the leaf extracts of all of the accessions ranged from 28.85 ± 1.53 µg mL−1 in MS-447 to 99.25 ± 1.63 µg mL−1 in MS-190. The antioxidant properties (ABTS) of the leaf extracts of all accessions ranged from 25.65 ± 2.06 in MS-258 to 83.62 ± 2.02 in MS-271. Pearson’s correlation analysis showed a significant and positive correlation between antioxidant activity and total phenolic content, and total flavonoid content varied widely among M. sacchariflorus accessions from the four geographical study regions. A strong and positive association was observed between DPPH with total phenolic content and total flavonoid content. Moderately positive correlations were observed between DPPH scavenging activity with gentisic acid, p-hydroxybenzoic acid, chlorogenic acid, p-coumaric acid, rutin, and quercetin (r = 0.385, r = 0.379, r = 0.362, r = 0.353, r = 0.490, and r = 0.372, respectively), suggesting that phenolic compounds are major contributors to the antioxidant potential of M. sacchariflorus. Thirty-two accessions collected from four different countries (China, Korea, Japan, and Russia) were characterized for 17 quantitative morphological traits. A wide range of diversity was observed in the morphological traits, with plant height ranging from 18.00 ± 1.00 cm to 163.20 ± 4.00 cm. Plant height was significantly correlated with biomass yield (fresh weight; r = 0.439, p < 0.05) and also had moderately positive correlations with culm length (r = 0.356, p < 0.05). Culm length was moderately correlated with the biomass yield fresh weight (r = 0.419*, p < 0.05) and the biomass yield dry weight (r = 0.425*, p < 0.05); however, it exhibited weak and negative correlations with compressed plant circumference (CCirc) (r = −0.374, p < 0.05) and total culm node number (TCmN) (r = −0.440, p < 0.05). Principal components analysis was performed to assess the variation in 17 morphological traits in 32 accessions of M. sacchariflorus. The first two principal components explained 51.24% of the morphological variations. A dendrogram generated from unweighted pair group method with arithmetic mean (UPGMA) clustering based on morphological characters was not found to be consistent with another dendrogram based on phytochemicals. In both cases, the number of studied accessions collected from different geographical regions grouped into two major groups. However, no clear correlation between these two different approaches was found. The substantial variation in the morphological traits, bioactive properties, and phenolic compounds among the accessions may provide useful information for breeding programs attempting to obtain M. sacchariflorus varieties with improved phenolic compounds traits and improved bioactive properties.

Reuniting the Biogeochemistry of Algae for a Low-Carbon Circular Bioeconomy.

Given their advantages of high photosynthetic efficiency and non-competition with land-based crops, algae, that are carbon-hungry and sunlight-driven microbial factories, are a promising solution to resolve energy crisis, food security, and pollution problems. The ability to recycle nutrient and CO2 fixation from waste sources makes algae a valuable feedstock for biofuels, food and feeds, biochemicals, and biomaterials. Innovative technologies such as the bicarbonate-based integrated carbon capture and algae production system (BICCAPS), integrated algal bioenergy carbon capture and storage (BECCS), as well as ocean macroalgal afforestation (OMA), can be used to realize a low-carbon algal bioeconomy. We review how algae can be applied in the framework of integrated low-carbon circular bioeconomy models, focusing on sustainable biofuels, low-carbon feedstocks, carbon capture, and advances in algal biotechnology.

Sustainable Lactic Acid Production from Lignocellulosic Biomass

Lignocellulosic biomass is a promising feedstock for sustainable biofuels and bioproducts. Among emerging bioproducts, lactic acid has attracted significant interest because of its growing application in many industries (e.g., packaging, medical, and pharmaceutical). In this study, BioSTEAM—an open-source platform—was leveraged for the design, simulation, and evaluation (via techno-economic analysis, TEA, and life cycle assessment, LCA) of lignocellulosic lactic acid biorefineries. With a minimum product selling price (MPSP) between $1.38 and 1.91 kg–1 (5th–95th percentiles, baseline at $1.57 kg–1), the biorefinery was capable of producing market-competitive lactic acid (market price between $1.7 and 2.1 kg–1), and its performance could be further enhanced (e.g., MPSP down to $1.09 kg–1, global warming potential of 2.79 kg CO2-eq·kg–1, and fossil energy consumption of 31.7 MJ·kg–1) with advancements in key technological parameters (fermentation yield and separation process conversions) and optimization in process operation. Sensitivity analyses focused on the fermentation unit (across titer, yield, and productivity; neutral vs low-pH fermentation) and feedstock characteristics (carbohydrate content and price) were also included to quantify their impact on the sustainability of the biorefinery. Overall, this research highlights the ability of agile TEA/LCA to screen promising biorefinery designs, prioritize research needs, and establish a road map for the continued development of bioproducts and biofuels.

“All We Want, Is to Get Rid of the Straw”: How Biofuel Policies Need to Be Multiple

Second-generation (2G) biofuels are promoted worldwide as remedy to sustainable-energy challenges in the transport sector and as response to the criticism of first-generation biofuels. By utilizing agriculture and forest residues, 2G biofuels claim to support agricultural livelihoods and boost rural economies. Quantitative estimates exist of the availability of “waste” or “unused” or “surplus” biomass that could be fed into producing bioenergy. Most of current discourse on 2G bioethanol is about developing efficient technologies and supportive policies for biomass utilization and energy distribution, while availability and supply of that biomass are often taken for granted. This paper challenges these presumptions of biomass availability and technological feasibility. Following a social-constructivist analysis of technology and focusing on how political actors, scientists, industry, green-revolution and organic farmers envision biomass, this paper argues that the innovation for 2G is hybrid and complex, rather than merely logistical and economic. Biomass as feedstock is not an off-the-shelf commodity, but a dynamic and fluid entity, the availability of which is dependent on a number of cultural, social, technological and economic factors. Policies are needed that recognize the multiplicity of agricultural practices if a sustainable biofuel system is to be developed.

Projections and Sustainability of Biofuels in India: Lessons for Punjab

This study analysed the potential and sustainability of biofuels blending in India. Thus, from the country’s potential and perspective, it has expounded the lessons for biofuels production in Punjab. Growth analysis has been computed using Compound Annual Growth Rate obtained from 2006-2013, and projections were estimated until 2025. The actual total demand of ethanol could meet onlythe 5 percent of fuel ethanol blending mandate of the country; therefore, the redistribution of total ethanol for fuel and other purposes could meet the 5 percent fuel ethanol demand. Also, Punjab could contribute its allocated share of fuel ethanol demand for meeting the country’s 5 percent blending target. However, the state could not meet the total ethanol demand as the total area required has been compromised. In biodiesel, 5 and 10 percent blending could effectively be achieved, taking the available area into concern. However, the present yield of biodiesel was insignificant, and the use of multiple feedstocks and Jatropha could meet only 0.01percent of the total blend rate.

Assessment of Molecular Diversity in Biofuel Crops.

Sustainable biofuel sources require the new sources of biofuel crops that can be developed into scalable plantation to meet the growing energy demands. Diverse supply sources of bioenergy plantations (edible, nonedible, and perennial grasses) will enable de-risking impact on geography and climate change that humans are likely to face in future. Use of phenotypic descriptors alone does not provide a deep insight into plantation population dynamics and molecular diversity of a biofuel crop. We provide protocols and methods to rapidly assess population parameters for emerging biofuel crops using genomics. This article has an application focus on next-generation sequencing to assess biofuel crop diversity. Use of these methods can accelerate germplasm assessment to accelerate population development and creation of sustainable biofuel plantations.

Bio-based Products from Lignocellulosic Waste Biomass

This review presents data on the chemical composition of harvest residues and food <br /> industry by-products as widely abundant representatives of lignocellulosic waste biomass. Pretreatment methods, with special emphasis on biological methods, are presented <br /> as an important step in utilization of lignocellulosic waste biomass for the production of <br /> sustainable biofuels and high-value chemicals. Special attention was paid to the methods <br /> of lignin isolation and its possible utilization within lignocellulosic biorefinery. The objectives of circular bioeconomy and the main aspects of lignocellulosic biorefinery are <br /> highlighted. Finally, current data on industrial, pilot, and research and development <br /> plants used in Europe for the production of a variety of bio-based products from different <br /> feedstocks are presented.

Harnessing Microbes to Produce Sustainable Plastics and Biofuels

Harnessing Microbes to Produce Sustainable Plastics and Biofuels

Algae: Biomass to Biofuel.

Worldwide demand for ethanol alternative fuel has been emerging day by day owing to the rapid population growth and industrialization. Culturing microalgae as an alternative feedstock is anticipated to be a potentially significant approach for sustainable bioethanol biofuel production. Microalgae are abundant in nature, which grow at faster rates with a capability of storing high lipid and starch/cellulose contents inside their cells. This process offers several environmental advantages, including the effective utilization of land, good CO2 sequestration without entering into "food against fuel" dispute. This chapter focuses on the methods and processes used for the production of bioethanol biofuels from algae. Thus, it also covers significant achievements in the research and developments on algae bioethanol production, mainly including pretreatment, hydrolysis, and fermentation of algae biomass. The processes of producing biodiesel, biogas, and hydrogen have also been discussed.

The future of Sustainable Biofuels towards the 2°C target: forecasting process, technologies and sector demands

Introducing sustainable fuels in the different transport fields in the EU is a very challenging goal, but also a clear priority in the EU decarbonization strategy. In fact, the transport sector is extremely rigid and regulated, with consolidated norms and standards and well-defined economics. Adding more oxygenated components to the fuel mix is also limited by the so-called blend-wall: thus, the share of renewable drop-in hydrocarbons has been recently growing worldwide and in the European Union. However, as a large part of these relates to lipids, the supply of sustainable feedstock has become the major critical element of the value chain. Fast-growing demand from new sectors as Aviation also emerged, that together with Heavy Duty and Maritime represent the focus of the EC strategy, complementary to the electrification of the road transport, passenger cars and light duty vehicles. Introducing innovative processes at full commercial scale requires to overcome the Mountain of Death of processes, where the bankability of not yet demonstrated technologies is the core problem. This work addresses the impact of the EU policy scenario, depicting the status of the different process and technologies, both Bio-based and Recycled Carbon, on the Mountain of Death.

Managing Plant Microbiomes for Sustainable Biofuel Production

The development of environmentally sustainable, economical, and reliable sources of energy is one of the great challenges of the 21st century. Large-scale cultivation of cellulosic feedstock crops (henceforth, bioenergy crops) is considered one of the most promising renewable sources for liquid transportation fuels. However, the mandate to develop a viable cellulosic bioenergy industry is accompanied by an equally urgent mandate to deliver not only cheap reliable biomass but also ecosystem benefits, including efficient use of water, nitrogen, and phosphorous; restored soil health; and net negative carbon emissions. Thus, sustainable bioenergy crop production may involve new agricultural practices or feedstocks and should be reliable, cost effective, and minimal input, without displacing crops currently grown for food production on fertile land. In this editorial perspective for the Phytobiomes Journal Focus Issue on Phytobiomes of Bioenergy Crops and Agroecosystems, we consider the microbiomes associated with bioenergy crops, the effects beneficial microbes have on their hosts, and potential ecosystem impacts of these interactions. We also address outstanding questions, major advances, and emerging biotechnological strategies to design and manipulate bioenergy crop microbiomes. This approach could simultaneously increase crop yields and provide important ecosystem services for a sustainable energy future.

Production Of Jatropha Biodiesel In Laboratory Scale

Abstract The paper presents how to convert jatropha curcas oil into biodiesel in Sudan. It Concerns the depletion of fossil fuel reserves and increasing prices of oil. The negative effects of fossil fuels on the environment and on human health have necessitated the creation of sustainable biofuels that will reduce our reliance on fossil fuels. Biodiesel which is made from animal fats and non-edible plant oil sources is classified as a sustainable, renewable, and eco-friendly source for biofuel. The method used consisted of a two-steps process, first, the esterification then followed by the transesterification process. There were some important factors that affected biodiesel production like molar ratio, temperature, and catalyst amount. The molar ratio of oil to methanol (1:6) with 5% (weight) of NaOH concentration was examined at a reaction temperature of about 60oC. The produced biodiesel’s specifications were analyzed and addressed. Kinematics viscosity was found to be about 5.251 mm2/s at 40C0, flashpoint value was 200 C0, density obtained was 0.8852 g/cm3 at 15C0 and the cloud point was found to be +9. The produced biodiesel was characterized and compared to standards biodiesel physical and fuel properties (D6751ASTM Standards). The work presented here introduces jatropha oil as a sustainable feedstock for biodiesel and may fill the gap of diesel production in the future.

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.

Occurrence of Botryococcus terribilis Komárek & Marvan in a small sandpit lake: The first report from Serbia

Alkaline saline ponds and lakes are habitats with unique biodiversity. The green alga of the genus Botryococcus was accidentally discovered during a micro-algal survey of these habitats in Serbia. Species B. terribilis was found and identified for the first time in Serbia in the small sandpit lake of the Rusanda Nature Park. The first sampling was incomplete due to the unknown origin of the orange-red surface scum. After the identity of the species had been confirmed, three additional samplings were conducted aiming to collect phytoplankton and water samples for physical and chemical analyses. Major anions and cations were analysed in order to characterize the chemical type of sandpit lake, as well as nutrient content. Sandpit lake is an alkaline water body that belongs to sodium bicarbonate chemical type. Morphometric analysis of B. terribilis was performed using light and transmission electron microscopy. B. terribilis was found to be numerous in the phytoplankton community in late autumn and winter. Species from the genus Botryococcus are known as a rich source of different lipids and this discovery can be the first step in the further biotechnological application of this species in sustainable biofuel production.

A novel integrated pathway for Jet Biofuel production from whole energy crops: A Jatropha curcas case study

The production of ‘Jet Biofuel’ has been identified as a promising strategy to mitigate the carbon footprint of the aviation sector. During the past decade, the commercial production of Jet Biofuel has attracted the attention of airline companies and governments across the globe. However, achieving a competitive production cost and sustainable Jet Biofuel remains a challenge. In this regard, various feedstocks have been tested for this purpose, where the vast majority have not complied with sustainability and feasibility expectations. Although not fully utilised in the Jet Biofuel industry, Jatropha curcas has emerged as one of the most promising feedstocks for Jet Biofuel production, since it is non-edible and is able to grow in non-arable lands with minimal water and energy requirements. This study presents a novel integrated pathway that utilises all parts of Jatropha fruit to produce a cost-effective Jet Biofuel using conventional hydroprocess, gasification, Fischer-Tropsch and reforming technologies. Different integration techniques are employed, including waste valorisation, by-products incorporation, as well as water, heat and power integration. The effect of various operating parameters on the products’ characteristics and yields has been evaluated. The model is validated against literature experimental data and demonstrates promising results. Whereby, 49 wt% of Jatropha fruit is converted into liquid fuels, with a Jet Biofuel selectivity of 65%, which represents an increment of almost 88% of Jet Biofuel yield compared to processing Jatropha oil alone. Furthermore, the system developed is power and water self-sufficient. The proposed pathway significantly lowers the production cost of Jet Biofuel below the market price of conventional Jet-A fuel for the base year of analysis, achieving a minimum selling price of 0.445 $/kg.

Stakeholders Mapping for Sustainable Biofuels: An Innovative Procedure Based on Computational Text Analysis and Social Network Analysis

The identification and engagement of stakeholders is a challenge whose outcomes have a strong impact on a project’s success. This is even more relevant when the project concerns the introduction of sustainable technologies; these technologies are often less competitive on the market than traditional ones, both in terms of development complexity and production costs. This paper presents a stakeholder identification and mapping procedure, based on an Interest x Influence model, that emphasizes a quantitative methodological approach. The method has been applied on publicly available online data to identify and map potential stakeholders of a European research project aiming at creating a new biomass-derived biofuel. A semi-supervised procedure, built by combining computational text analysis and social network analysis techniques, has been used to calculate Interest and Influence scores for each potential stakeholder toward the project. The results show that stakeholders can be ranked on both dimensions and mapped on a bi-dimensional space according to their level of Interest and Influence. Within projects aiming at developing technologies for sustainability in which a wide range of stakeholders are involved at a transnational level, this stakeholder mapping technique provides a useful tool that can be adopted even with little knowledge on specific fields of application. A further asset of this approach lies in the possibility of profiling stakeholders on the basis of their Interest in the target project: this allows us to know the contents of a stakeholder (or stakeholders category) Interest, and therefore to have useful information for addressing the targeted stakeholder by means of a content design which is based on specific content categories, substantiating the stakeholder(s) Interest in the specific project.

Deoxygenation of Bio‐oil from Calcium‐Rich Paper‐Mill Waste

AbstractDe‐inking sludge, an ash‐rich recycling paper solid waste, is generated in huge amounts. The catalytic deoxygenation potential of calcium‐based de‐inking sludge in co‐pyrolysis mode with wood and its neat thermal conversion to sustainable biofuels are investigated. Wood, de‐inking sludge, and their blends are processed in a thermocatalytic reforming (TCR) system. In the presence of de‐inking sludge, the oxygen content in the organic phase decreases and the bio‐oil calorific value improves as compared to the neat wood‐derived bio‐oil. The TCR processing of neat de‐inking sludge produces a bio‐oil with low oxygen content and higher calorific value.