Production Of Renewable Biofuels Research Articles

A nanoscale investigation of the formation of mesostructured zeolites FAU and LTL

Nanostructured materials can be utilised as potential catalysts for the production of platform chemicals and renewable biofuels from biomass derived molecules. The formation of hierarchical meso-microporous zeolites LTL and FAU via the surfactant assisted tandem acid-base post-synthesis treatment has been investigated by time-resolved in situ synchrotron SAXS and WAXS, providing a new insight into the mechanism of the mesostructuring treatment. Based on the results of TEM and in situ synchrotron measurements, a model for the formation of the core-shell structure of LTL zeolite crystals is proposed. Complementary evaluation using FTIR, NMR and nitrogen adsorption, in conjunction with reaction studies on mesostructured zeolites, demonstrated a potential for enhanced catalytic performance of these materials owing to the increased accessibility of the active sites and reduced transport limitations.

Recent developments on sustainable biobutanol production: a novel integrative review.

Renewable and sustainable biofuel production, such as biobutanol, is becoming increasingly popular as a substitute for non-renewable and depleted petrol fuel. Many researchers have studied how to produce butanol cheaply by considering appropriate feedstock materials and bioprocess technologies. The production of biobutanol through acetone-butanol-ethanol (ABE) is highly sought after around the world because of its sustainable supply and lack of competition with food. The purpose of this study is to present the current biobutanol production research and to analyse the biobutanol research conducted during 2006 to 2023. The keyword used in this study is "Biobutanol," and the relevant data was extracted from the Web of Science database (WoS). According to the results, institutions and scholars from the People's Republic of China, the USA, and India have the highest number of cited papers across a broad spectrum of topics including acetone-butanol-ethanol (ABE) fermentation, biobutanol, various pretreatment techniques, and pervaporation. The success of biobutanol fermentation from biomass depends on the ability of the fermentation operation to match the microbial behaviour along with the appropriate bioprocessing strategies to improve the entire process to be suitable for industrial scale. Based on the review data, we will look at the biobutanol technologies and appropriate strategies that have been developed to improve biobutanol production from renewable biomass.

Catalytic pyrolysis of fish waste oil using ZSM-5 catalyst for the production of renewable biofuel

This present study enlightens the eco-friendly green synthesis of ZSM-5 from natural clay montmorillonite, and its proper incorporation with ‘Ni’. Nickle (Ni) was wet impregnated onto HZSM-5 and the resulting catalyst was characterized by various techniques including XRD, BET, N2 Sorption Studies, TPD, SEM and TEM techniques. The SEM images revealed the uniform distribution of Ni over HZSM-5 zeolite catalyst and the XRD results indicated the undistorted crystalline structure of HZSM-5 even after impregnation of Ni. The latter part of the work concentrates on the strength of the catalyst in cracking oil derived from discarded fish parts. Discarded fish waste was pyrolyzed to obtain the fish oil, which was then used for cracking studies. The fish oil was efficiently converted (99% conversion) by Ni/ZSM5 (50 wt %) and yielded 70% liquid fractions, which formed gasoline (78.6%), kerosene (12.3%) and diesel (9.1%). The research is a complete parcel to examine the working potential of the produced biofuel in pre-existing engines. The quality of gasoline fraction was tested according to ASTM standards, which showed that the heating value was slightly lower compared to fossil gasoline. The torque and brake fuel consumption were also examined and it indicated that the fish oil derived gasoline fuel may need to be mixed with the commercial gasoline to optimize its performance.

Nonsterile Process for Biohydrogen Production: Recent Updates, Challenges, and Opportunities.

Hydrogen (H2), a clean and versatile energy carrier, has recently gained significant attention as a potential solution for reducing carbon emissions and promoting sustainable energy systems. The yield and efficiency of the biological H2 production process primarily depend on sterilization conditions. Various strategies, such as heat inactivation and membrane-based sterilization, have been used to achieve desirable yields via microbial fermentation. Almost every failed biotransformation process is linked to nonsterile conditions at any reaction stage. Therefore, the production of renewable biofuels as alternatives to fossil fuels is more attractive. Pure sugars have been widely documented as a costly feedstock for H2 production under sterile conditions. Biotransformation under nonsterile conditions is more desirable for stable and sustainable operation. Low-cost feeds, such as biowaste, are considered suitable alternatives, but they require appropriate sterilization to overcome the limitations of inherited or contaminating microbes during H2 production. This article describes the status of microbial fermentative processes for H2 production under nonsterile conditions and discusses strategies to improve such processes for sustainable, cleaner production.

Reaction Mechanisms of Fe‐Dependent Fatty Acid Decarboxylases

AbstractThe escalating demand for fossil fuels has raised environmental concerns, urging the exploration of biosynthetic pathways for renewable hydrocarbon fuels. Terminal alkenes (α‐alkenes) emerge as “drop‐in” compatible fuels and chemicals, holding the potential to replace traditional fossil fuels. Fatty acid decarboxylases present a promising route for converting fatty acids into α‐alkenes, underscoring the imperative need for comprehending the catalytic mechanisms governing these enzymes in the quest for renewable biofuel production. The reported fatty acid decarboxylases entail the involvement of heme and non‐heme iron cofactors in the redox process. In this review, we summarize the reaction mechanisms of four iron‐dependent fatty acid decarboxylases (OleTJE, OleTPRN, UndA, and UndB), providing a critical analysis of the factors influencing chemical selectivity and catalytic performance.

Production of Renewable Hydrocarbon Biofuels with Lignocellulose and Its Derivatives over Heterogeneous Catalysts.

In recent years, the issues of global warming and CO2 emission reduction have garnered increasing global attention. In the 21st Conference of the Parties (convened in Paris in 2015), 179 nations and the European Union signed a pivotal agreement to limit the global temperature increase of this century to well below 2 K above preindustrial levels. To fulfill this objective, extensive research has been conducted to use renewable energy sources as potential replacements for traditional fossil fuels. Among them, the production of hydrocarbon transportation fuels from CO2-neutral and renewable biomass has proven to be a particularly promising solution due to its compatibility with existing infrastructure. This review systematically summarizes research progress in the synthesis of liquid hydrocarbon biofuels from lignocellulose during the past two decades. Based on the chemical structure (including n-paraffins, iso-paraffins, aromatics, and cycloalkanes) of hydrocarbon transportation fuels, the synthesis pathways of these biofuels are discussed in four separate sections. Furthermore, this review proposes three guiding principles for the design of practical hydrocarbon biofuels, providing insights into future directions for the development of viable biomass-derived liquid fuels.

Simultaneous glucose and xylose utilization by an Escherichia coli catabolite repression mutant.

As advances are made toward the industrial feasibility of mass-producing biofuels and commodity chemicals with sugar-fermenting microbes, high feedstock costs continue to inhibit commercial application. Hydrolyzed lignocellulosic biomass represents an ideal feedstock for these purposes as it is cheap and prevalent. However, many microbes, including Escherichia coli, struggle to efficiently utilize this mixture of hexose and pentose sugars due to the regulation of the carbon catabolite repression (CCR) system. CCR causes a sequential utilization of sugars, rather than simultaneous utilization, resulting in reduced carbon yield and complex process implications in fed-batch fermentation. A mutant of the gene encoding the cyclic AMP receptor protein, crp*, has been shown to disable CCR and improve the co-utilization of mixed sugar substrates. Here, we present the strain construction and characterization of a site-specific crp* chromosomal mutant in E. coli BL21 star (DE3). The crp* mutant strain demonstrates simultaneous consumption of glucose and xylose, suggesting a deregulated CCR system. The proteomics further showed that glucose was routed to the C5 carbon utilization pathways to support both de novo nucleotide synthesis and energy production in the crp* mutant strain. Metabolite analyses further show that overflow metabolism contributes to the slower growth in the crp* mutant. This highly characterized strain can be particularly beneficial for chemical production by simultaneously utilizing both C5 and C6 substrates from lignocellulosic biomass.IMPORTANCEAs the need for renewable biofuel and biochemical production processes continues to grow, there is an associated need for microbial technology capable of utilizing cheap, widely available, and renewable carbon substrates. This work details the construction and characterization of the first B-lineage Escherichia coli strain with mutated cyclic AMP receptor protein, Crp*, which deregulates the carbon catabolite repression (CCR) system and enables the co-utilization of multiple sugar sources in the growth medium. In this study, we focus our analysis on glucose and xylose utilization as these two sugars are the primary components in lignocellulosic biomass hydrolysate, a promising renewable carbon feedstock for industrial bioprocesses. This strain is valuable to the field as it enables the use of mixed sugar sources in traditional fed-batch based approaches, whereas the wild-type carbon catabolite repression system leads to biphasic growth and possible buildup of non-preferential sugars, reducing process efficiency at scale.

Anaerobic digestion of vinasse improves its use as a liquid fertilizer

The global demand for exploiting the potential of renewable biofuel production is increasing. When countries with large agricultural areas produce ethanol, they also generate a harmful byproduct called vinasse. Vinasse is a dark brown effluent that contains a high amount of organic matter, has an acidic nature, and is rich in mineral salts. Managing this effluent poses a challenge due to its significant volume, which ranges from 8 to 20 liters per liter of ethanol produced. Traditionally, raw vinasse has been applied directly to the soil as a liquid fertilizer. However, this practice, without proper guidance, can lead to soil degradation, micronutrient imbalance, pH change and excessive accumulation of organic matter. To resolve these issues and still use vinasse as a fertilizer, the process of anaerobic degradation of vinasse in biodigesters was analyzed. The resulting treated effluent, known as digested vinasse, was then compared to raw vinasse in terms of pollution parameters and the balance of minerals crucial for sugarcane cultivation. The results demonstrated a significant reduction in the organic load of vinasse, with a removal of chemical oxygen demand (COD) ranging from 66% to 85%. After applying the digested vinasse to sugarcane like cultivation soil, a noticeable decrease in the environmental impact caused by excessive organic matter was observed. Additionally, the study found that important nutritional elements such as sodium (Na) did not have any adverse effects or accumulate excessively when compared to calcium (Ca) and magnesium (Mg). In conclusion, the research demonstrates that the anaerobic degradation of vinasse in biodigesters can effectively reduce its organic load and mitigate the environmental impact associated with the direct application of raw vinasse to agricultural soils

Adsorption-driven reverse osmosis separation of ethanol/water using zeolite nanosheets.

Developing more energy-efficient and cost-effective membrane processes for the separation of ethanol and water represents a strategically important direction to facilitate the production of renewable biofuels. In this study, by employing state-of-the-art molecular simulations, the potential of zeolite nanosheets as reverse osmosis (RO) membranes in ethanol/water separation is investigated. These materials are predicted to offer unprecedentedly high fluxes and more importantly, the ethanol-to-water separation factor can be as large as approximately 800 if the structure is meticulously selected. The separation achieved herein can in fact be considered counter-intuitive as the membrane allows the larger ethanol molecules to permeate through while blocking smaller water molecules. Further investigations reveal that the observed selectivity is strongly correlated with the adsorption selectivity of the bulk materials, suggesting an adsorption-driven mechanism. Promising candidates also appear to have the largest cavity diameter of approximately 6 Å, a size that can be commensurate with the dimensions of ethanol to facilitate its adsorption. The hydrophilicity on the membrane surfaces is as well found to play a non-negligible role. Overall, this study demonstrates the great promise of zeolite nanosheets as RO membranes for extracting anhydrous ethanol from its aqueous mixture and provides guidance toward the selection of promising membrane candidates.

Resorufin retainment by extracellular DNA ensures efficient extracellular electron transfer of Geobacter biofilm

Electrochemically active bacteria (EAB) have promising applications in renewable energy recovery, biofuel production, environmental remediation, and wastewater treatment. Resazurin (RZ) is an effective exogenous electron mediator to facilitate extracellular electron transfer (EET) in EAB, but it is not fully understood that how it catalyzes EET within thick electroactive biofilm. Using Geobacter sulfurreducens as a model EAB, this study investigated the effect and mechanisms of RZ-mediated electron transfer in anode biofilm in a bioelectrochemical system. It was found that the amendment of RZ substantially enhanced current generation of anode biofilm, and the facilitating effect of RZ remained even after fresh electrolyte replacement without RZ replenishment. As an intermediate product of RZ, resorufin (RR) was the actual electron shuttle retained within the entire anode biofilm, responsible for the observed stable electron shuttling efficiency. The retention of RR in anode biofilm might be the consequences of insoluble RR deposition and RR binding with extracellular DNA (eDNA) through intercalative interactions. This study provided in vivo and in vitro evidences for the first time that eDNA provided binding sites for RR in Geobacter biofilm, and proposed a novel electron shuttling mechanism of phenoxazine catalyzing efficient EET of electroactive biofilm.

Valeric Biofuels from Biomass-Derived γ-Valerolactone: A Critical Overview of Production Processes.

This review analyzes critically the production of valeric biofuels from γ-valerolactone, a relevant biomass-derived platform molecule. Initially, the main properties of valeric esters as fuels for spark- and compression-ignition engines are summarized. Then, catalytic routes to valeric esters from γ-valerolactone are meticulously analyzed, describing the acid- and metal-catalyzed reactions taking part in the tandem catalysis. Only works focused on the production of the valeric biofuels were considered, excluding the cases where these esters were observed in minor amounts or as byproducts. The role of the appropriate selection of the support, catalytic species, catalyst preparation and experimental conditions on the valeric ester productivity are thoroughly commented. Finally, some concluding remarks and perspectives are given, mentioning the areas where additional efforts must be done in order to turn the dream of a massive and renewable valeric biofuel production into a reality.

Exploring the Critical Factors of Biomass Pyrolysis for Sustainable Fuel Production by Machine Learning

The goal of this study is to use machine learning methodologies to identify the most influential variables and optimum conditions that maximize biochar, bio-oil, and biogas yields for slow pyrolysis. First, experimental results reported in 37 articles were compiled into a database. Then, an explainable machine learning approach, Shapley Additive exPlanations (SHAP), was employed to find the effects of descriptors on the targets, and it was found that higher biochar yields can be obtained at lower temperatures using biomass with low volatile matter and high ash content. Following that, decision tree classification was used to discover the variables leading to high levels of the targets, and the most generalizable path for high biogas yield was found to be where the maximum particle diameter was less than or equal to 6.5 mm and the temperature was greater than 912 K. Finally, association rule mining models were created to find associations of descriptors with very high levels of yields, and among many findings, it was discovered that biomass with larger particles cannot be converted into bio-oil efficiently. It was then concluded that machine learning methods can help to determine the best slow pyrolysis conditions for the production of renewable and sustainable biofuels.

Economic and environmental viability of biofuel production from organic wastes: A pathway towards competitive carbon neutrality

Production of renewable C1 transport biofuels (such as biomethane and biomethanol) through the integration of anaerobic digestion (AD) with carbon capture, utilization and sequestration technologies may offer a solution to reduce greenhouse gas (GHG) emissions. This paper presented a detailed techno-economic and environmental assessment of four cases for biomethane or biomethanol production by incorporating AD, CO2 utilization via biomethanation (CU), solid digestate pyrolysis (Py) and methanol synthesis (MeOH). The results reflected the current state of technologies and potential future scenarios within a mature market. Under optimistic scenarios (scaled-up systems and reduced hydrogen price of 1 €/kg), the minimum potential GHG abatement cost for the AD-Py-CU case was −111.1 €/t CO2-eq when biomethane was sold at 1.03 €/Nm3 (a contract gas price in 2022), while the abatement cost rose to −58.2 €/t CO2-eq when H2 was purchased at 3.40 €/kg. When methanol was sold at 425 €/t (global weighted average value), the marginal abatement cost for the AD-Py-CU-MeOH (with H2 at 1.0 €/kg) case was 136.5 €/t CO2-eq, which is higher than current carbon credits at 33.5 €/t CO2. This study suggests that biomethane produced by incorporating AD, CO2 biomethanation and pyrolysis technologies may be economically and environmentally competitive over natural gas.

Solvent assisted to prepare shell structured Cu/γ-Al2O3 catalyst with low Cu content for oil efficient hydrodeoxygenation to high-quality biofuel

Using biomass “green carbon” can effectively alleviate the energy crisis and environmental protection problems. To achieve efficient removal of oxygen atoms, retain complete carbon chain structures, and maximize the economy of carbon atoms for the inedible or waste bio-oils, a novel and unique shell-style Cu/γ-Al2O3 catalyst with low Cu content was developed to solve the current problems including easy sintering and poor hydrodeoxygenation (HDO) activity of the studied catalysts. The shell Cu/γ-Al2O3 catalyst (Cu-CPA) with the Cu content of 3 wt% prepared by acetone as solvent has excellent cycle-stable HDO performances, the methyl laurate hydrogen conversion and C12 alkanes selectivity were 87.2 and 80.0 % at 400 °C, respectively, which were equivalent to the activities of the ordinary 10 wt% Cu/γ-Al2O3 catalyst prepared by wet impregnation using water as a solvent. The polarity of the impregnating solution modulates the shell layer thickness of the Cu-based catalysts to improve the surface chemical composition and pore structure of the catalysts, which in turn affects the lipids HDO performances of the corresponding catalyst. Active heterogeneous shell Cu-CPA catalyst showed high activity, selectivity, and stability in HDO, which can be attributed to the unique structure with suitable active shell thickness and high utilization rate of the metal Cu active components. This study provides feasible ideas for the preparation of shell-type catalysts, the design of anti-sintering Cu-based catalysts, and the production of renewable biofuels.

Bioethanol Production Based on Saccharomyces cerevisiae: Opportunities and Challenges

The large consumption of non-renewable fossil fuels has brought about energy depletion and environmental pollution, spawning the production of renewable biofuels, an important alternative to alleviate the energy crisis effectively. As one of the ideal types of biofuel, bioethanol synthesis in Saccharomyces cerevisiae has attracted much attention. S. cerevisiae has been developed as essential chassis cells with high efficiency for bioethanol synthesis on account of many advantages. This study systematically summarized the preponderance of S. cerevisiae in biosynthesis. It objectively stated the research strategies of bioethanol synthesis based on S. cerevisiae and the existing bottleneck problems. This study further proposed reasonable prospects for bioethanol synthesis by S. cerevisiae, attempting to provide alternative research strategies.

Recent Advances of Triglyceride Catalytic Pyrolysis via Heterogenous Dolomite Catalyst for Upgrading Biofuel Quality: A Review.

This review provides the recent advances in triglyceride catalytic pyrolysis using heterogeneous dolomite catalysts for upgrading biofuel quality. The production of high-quality renewable biofuels through catalytic cracking pyrolysis has gained significant attention due to their high hydrocarbon and volatile matter content. Unlike conventional applications that require high operational costs, long process times, hazardous material pollution, and enormous energy demand, catalytic cracking pyrolysis has overcome these challenges. The use of CaO, MgO, and activated dolomite catalysts has greatly improved the yield and quality of biofuel, reducing the acid value of bio-oil. Modifications of the activated dolomite surface through bifunctional acid-base properties also positively influenced bio-oil production and quality. Dolomite catalysts have been found to be effective in catalyzing the pyrolysis of triglycerides, which are a major component of vegetable oils and animal fats, to produce biofuels. Recent advances in the field include the use of modified dolomite catalysts to improve the activity and selectivity of the catalytic pyrolysis process. Moreover, there is also research enhancement of the synthesis and modification of dolomite catalysts in improving the performance of biofuel yield conversion. Interestingly, this synergy contribution has significantly improved the physicochemical properties of the catalysts such as the structure, surface area, porosity, stability, and bifunctional acid-base properties, which contribute to the catalytic reaction's performance.

Hollow ZSM-5 encapsulated with single Ga-atoms for the catalytic fast pyrolysis of biomass waste

The development of efficient metal-zeolite bifunctional catalysts for catalytic fast pyrolysis (CFP) of biomass waste is highly desirable for bioenergy and renewable biofuel production. However, conventional metal-loaded zeolites often suffer from metal sintering during pyrolysis and are thus inactivated. In this study, single-site Ga-functionalized hollow ZSM-5 (GaOx@HS-Z5) was synthesized via an impregnation-dissolution-recrystallization strategy without H2 reduction. The Ga atom was coordinated to four oxygen atoms in HS-Z5 frameworks. Benefitting from the highly dispersed single-Ga atoms and hollow zeolite framework, 3GaOx@HS-Z5 performed the best in producing hydrocarbon-rich bio-oil compared to impregnated 3GaOx/HS-Z5 and H2-reduced 3Ga@HS-Z5 in the maize straw CFP. In particular, 3GaOx@HS-Z5 delivered the highest bio-oil yield (23.6 wt%) and hydrocarbon selectivity (49.4 area%). 3GaOx@HS-Z5 also retained its structural integrity and catalytic activity after five pyrolysis-regeneration cycles, demonstrating its advantage in practical biomass CFP. The elimination of H2 reduction during the synthesis of catalyst provides an additional advantage for simplifying the CFP process and reducing operating costs. The retained Ga micro-environment and anti-sintering properties were unique for 3GaOx@HS-Z5, as severe metal sintering occurred during pyrolysis for other metals (e.g., NiOx, ZnOx, FeOx, and CoOx) that encapsulated HS-Z5.

Syngas methanation over a metal hydride catalyst: Technology performance, efficiency and economic profitability

In the last decade, biomass has been considered one of the main renewable energy sources to replace fossil fuels and consequently, biomass conversion technologies for the production of alternative fuels will play a specific role in the future energy as green biofuels for the transport sector or a power generation at small-scale distributed plants. During the thermal conversion - gasification, biomass is converted into more valuable products - syngases which could be used for biomethane production. Though, some challenges still exist related to the broad applicability of the thermal conversion of biomass to biomethane: costly short-life catalysts and a low conversion efficiency due to the high amount of carbon monoxide/dioxide in syngas.To overcome these challenges, an innovative biomethane production concept based on the plasma-assisted gasification and conversion of synthetic gases to biomethane was developed and tested, including research on the adaptability of two catalysts, magnesium nickel and magnesium nickel hydride, for raw syngas conversion. The performance of catalysts was investigated in a fixed bed type reactor using raw syngas obtained from plasma-assisted gasification.The results indicate the magnesium nickel hydride catalysts' good activity and functionality for converting carbon dioxide and carbon monoxide-containing syngas. A high conversion of 0.997 is reached. Determined that the surplus of hydrogen promotes the conversion of carbon oxides, though the volumetric concentration of methane (the maximum of 86.4 vol%) in product gas is reduced. Considering that the developed technology concept can be integrated into small combined heat and power plants, bio-waste generating plants, or decentralized areas as an additional source of renewable energy or biofuel production, the energy-mass balance and economic analysis for the optimization of 1 MWh bio-CH4 production concept was provided.

Co-pyrolysis of lignocellulosic biomass with other carbonaceous materials: A review on advance technologies, synergistic effect, and future prospectus

Due to the continuous rise in population, modernization, and industrialization, the demand for energy is increasing day by day, resulting in serious issues such as fossil fuel depletion, pollution, and power shortages. As a result, there is an urgent need to investigate alternate energy sources. Lignocellulosic biomass pyrolysis has been shown as the most promising feedstock for the production of sustainable and renewable biofuels. Unfortunately, the fuel characteristics of bio-oil generated from biomass pyrolysis are still insufficient to meet petroleum products ASTM standards. To address these challenges, co-pyrolysis of lignocellulosic biomass with other carbonaceous materials (e.g., plastic waste, Tyre garbage etc.) is emerging as one of the most promising approaches. Various experimental studied have been conducted on lignocellulosic biomasses co-pyrolysis with other carbonaceous materials such as plastic waste, tire waste, coal, algae and sewage sludge. The present manuscript aims to review and establish the scope of co-pyrolysis of lignocellulosic biomass with various carbon rich feedstocks for renewable production of high-quality renewable fuels. The synergistic effect between lignocellulosic biomass and other carbonaceous materials has been explored in detail. Furthermore, recent advances in co-pyrolysis process along with the reaction affecting parameters are also summarized in brief. Consequently, this review demonstrates both highlights of the remarkable achievement of co-pyrolysis and the milestones that are necessary to be garnered in the future.

The growth, lipid accumulation and adaptation mechanism in response to variation of temperature and nitrogen supply in psychrotrophic filamentous microalga Xanthonema hormidioides (Xanthophyceae)

BackgroundMicroalgae are promising feedstocks for production of renewable biofuels and value-added bioproducts. Temperature and nitrogen supply are important environmental and nutritional factors affecting the growth and metabolism of microalgae, respectively. In this study, the growth and lipid accumulation of filamentous microalgae Xanthonema hormidioides under different temperatures (5, 7, 10, 15, 20, 25, 27 and 30 °C) and initial nitrogen concentrations (3, 9, 18 mM) were investigated, and its adaptive mechanisms of tolerance to low temperature and nitrogen stress were analysis by proteomics.ResultsThe optimum temperature range for the growth of X. hormidioides was between 15 and 20 °C, and the algal cells had slow growth rate at 5 °C and could not survive at 30 °C. The maximum biomass concentration was 11.73 g L−1 under the temperature of 20 °C, and the highest total lipid content was 56.63% of dry weight. Low temperature did not change the fatty acids profiles but promoted the accumulation of unsaturated fatty acids of X. hormidioides. The maximum contents of palmitoleic acid, eicosapentaenoic acid and total fatty acid were 23.64%, 2.49% and 41.14% of dry weight, respectively. Proteomics was performed under three temperature (7, 15, 25 °C), two nitrogen concentrations (3 and 18 mM) and two cultivation times (day 3 and 12). A total of 6503 proteins were identified. In the low temperature, photosynthesis-related proteins were down-regulated to protect the photosynthetic apparatus. The up-regulation of key enzymes DGAT and PDAT demonstrated the accumulation of TAGs under low nitrogen treatment. The proteins related to ribosome, phosphatidylinositol signaling system, antioxidant system and cold shock proteins (CSPs) in X. hormidioides were co-upregulated under the treatment of low temperature, which can alleviate the damages induced by temperature stress and maintain the normal growth and metabolism of algal cells.ConclusionsX. hormidioides is a psychrotolerant microalga. It is an oleaginous filamentous microalga containing hyper palmitoleic acid and a certain amount of eicosapentaenoic acid with great potential for biofuel development, as well as for applications in nutritional health products and other industries.