Biodiesel from oil produced in vegetative tissues of biomass - A review

Sorghum: A Multipurpose Crop

Sorghum (Sorghum bicolor L.) is one of the top five cereal crops in the world in terms of production and planting area and is widely grown in areas with severe abiotic stresses such as drought and saline-alkali land due to its excellent stress resistance. Moreover, sorghum is a rare multipurpose crop that can be classified into grain sorghum, energy sorghum, and silage sorghum according to its domestication direction and utilization traits, endowing it with broad breeding and economic value. In this review, we mainly discuss the latest research progress and regulatory genes of agronomic traits of sorghum as a grain, energy, and silage crop, as well as the future improvement direction of multipurpose sorghum. We also emphasize the feasibility of cultivating multipurpose sorghum through genetic engineering methods by exploring potential targets using wild sorghum germplasm and genetic resources, as well as genomic resources.

Advanced biofuel production, policy and technological implementation of nano-additives for sustainable environmental management - A critical review

This review article critically evaluates the significance of adopting advanced biofuel production techniques that employ lignocellulosic materials, waste biomass, and cutting-edge technology, to achieve sustainable environmental stewardship. Through the analysis of conducted research and development initiatives, the study highlights the potential of these techniques in addressing the challenges of feedstock supply and environmental impact and implementation policies that have historically plagued the conventional biofuel industry. The integration of state-of-the-art technologies, such as nanotechnology, pre-treatments and enzymatic processes, has shown considerable promise in enhancing the productivity, quality, and environmental performance of biofuel production. These developments have improved conversion methods, feedstock efficiency, and reduced environmental impacts. They aid in creating a greener and sustainable future by encouraging the adoption of sustainable feedstocks, mitigating greenhouse gas emissions, and accelerating the shift to cleaner energy sources. To realize the full potential of these techniques, continued collaboration between academia, industry representatives, and policymakers remains essential.

Improved bioenergy value of residual rice straw by increased lipid levels from upregulation of fatty acid biosynthesis

BACKGROUND

Rice (Oryza sativa) straw is a common waste product that represents a considerable amount of bound energy. This energy can be used for biogas production, but the rate and level of methane produced from rice straw is still low. To investigate the potential for an increased biogas production from rice straw, we have here utilized WRINKLED1 (WRI1), a plant AP2/ERF transcription factor, to increase triacylglycerol (TAG) biosynthesis in rice plants. Two forms of Arabidopsis thaliana WRI1 were evaluated by transient expression and stable transformation of rice plants, and transgenic plants were analyzed both for TAG levels and biogas production from straw.

RESULTS

Both full-length AtWRI1, and a truncated form lacking the initial 141 amino acids (including the N-terminal AP2 domain), increased fatty acid and TAG levels in vegetative and reproductive tissues of Indica rice. The stimulatory effect of the truncated AtWRI1 was significantly lower than that of the full-length protein, suggesting a role for the deleted AP2 domain in WRI1 activity. Full-length AtWRI1 increased TAG levels also in Japonica rice, indicating a conserved effect of WRI1 in rice lipid biosynthesis. The bio-methane production from rice straw was 20% higher in transformants than in the wild type. Moreover, a higher producing rate and final yield of methane was obtained for rice straw compared with rice husks, suggesting positive links between methane production and a high amount of fatty acids.

CONCLUSIONS

Our results suggest that heterologous WRI1 expression in transgenic plants can be used to improve the metabolic potential for bioenergy purposes, in particular methane production.

Sustainable Refining of Vegetable Oil Made Easy with a Designer Phospholipase C Enzyme

The increasing demand pressures the vegetable oil industry to develop novel refining methods. Degumming with type C phospholipases (PLCs) is a green technology and provides extra oil. However, natural PLCs are not active under the harsh conditions used in oil refining plants, requiring additional unit operations. These upfront capital expenditures and the associated operational costs hinder the adoption of this method. Here, we present a process based on ChPLC, a synthetic PLC obtained by consensus sequence design, possessing superior thermal stability and catalytic properties. Using ChPLC, crude soybean oil degumming was completed at 80 °C in 30 min, the temperature and residence time imposed by the design of existing oil refining plants. Remarkably, an extra yield of oil of 2% was obtained using 60% of the dose recommended for PLCs marketed today, saving upfront investments and reducing the operational cost of degumming. A techno-economic analysis indicates that, for medium size plants, ChPLC reduces the overall cost of soybean oil enzymatic degumming by 58%. The process presented here facilitates the implementation of enzymatic technologies to oil producers, regardless of their processing capacity, bringing potential annual benefits in the billion-dollar range for the global economy.

Critical review of biochemical pathways to transformation of waste and biomass into bioenergy

In recent years, biofuel or biogas have become the primary source of bio-energy, providing an alternative to conventionally used energy that can meet the growing energy demand for people all over the world while reducing greenhouse gas emissions. Enzyme hydrolysis in bioethanol production is a critical step in obtaining sugars fermented during the final fermentation process. More efficient enzymes are being researched to provide a more cost-effective technique during enzymatic hydrolysis. The exploitation of microbial catabolic biochemical reactions to produce electric energy can be used for complex renewable biomasses and organic wastes in microbial fuel cells. In hydrolysis methods, a variety of diverse enzyme strategies are used to promote efficient bioethanol production from various lignocellulosic biomasses like agricultural wastes, wood feedstocks, and sea algae. This paper investigates the most recent enzyme hydrolysis pathways, microbial fermentation, microbial fuel cells, and anaerobic digestion in the manufacture of bioethanol/bioenergy from lignocellulose biomass.

Using systems metabolic engineering strategies for high-oil maize breeding

Maize oil, which is a blend of fatty acid esters generated from triacylglycerol (TAG), is an important component of maize-derived food, feed, and biofuel. The kernel oil content in commercial high-oil maize hybrids averages ∼8%, which is far lower than that in developed high-oil maize lines (as high as 20%). Advances in high-oil maize genomics and genetics and the development of systems metabolic engineering technologies provide new opportunities for high-oil maize breeding. In this review, we discuss the possibility of using kernels and vegetative tissues as factories to produce TAG, eicosapentaenoic acid, and docosahexaenoic acid. We further propose specific implementation strategies based on the metabolic engineering of other species to develop transgenic and gene-editing products, as well as traditional breeding strategies, for application in high-oil maize breeding programs.

Progress in understanding and improving oil content and quality in seeds

The world's population is projected to increase by two billion by 2050, resulting in food and energy insecurity. Oilseed crops have been identified as key to address these challenges: they produce and store lipids in the seeds as triacylglycerols that can serve as a source of food/feed, renewable fuels, and other industrially-relevant chemicals. Therefore, improving seed oil content and composition has generated immense interest. Research efforts aiming to unravel the regulatory pathways involved in fatty acid synthesis and to identify targets for metabolic engineering have made tremendous progress. This review provides a summary of the current knowledge of oil metabolism and discusses how photochemical activity and unconventional pathways can contribute to high carbon conversion efficiency in seeds. It also highlights the importance of ¹³C-metabolic flux analysis as a tool to gain insights on the pathways that regulate oil biosynthesis in seeds. Finally, a list of key genes and regulators that have been recently targeted to enhance seed oil production are reviewed and additional possible targets in the metabolic pathways are proposed to achieve desirable oil content and quality.

A toolkit for plant lipid engineering: Surveying the efficacies of lipogenic factors for accumulating specialty lipids

Plants produce energy-dense lipids from carbohydrates using energy acquired via photosynthesis, making plant oils an economically and sustainably attractive feedstock for conversion to biofuels and value-added bioproducts. A growing number of strategies have been developed and optimized in model plants, oilseed crops and high-biomass crops to enhance the accumulation of storage lipids (mostly triacylglycerols, TAGs) for bioenergy applications and to produce specialty lipids with increased uses and value for chemical feedstock and nutritional applications. Most successful metabolic engineering strategies involve heterologous expression of lipogenic factors that outperform those from other sources or exhibit specialized functionality. In this review, we summarize recent progress in engineering the accumulation of triacylglycerols containing - specialized fatty acids in various plant species and tissues. We also provide an inventory of specific lipogenic factors (including accession numbers) derived from a wide variety of organisms, along with their reported efficacy in supporting the accumulation of desired lipids. A review of previously obtained results serves as a foundation to guide future efforts to optimize combinations of factors to achieve further enhancements to the production and accumulation of desired lipids in a variety of plant tissues and species.

Organic waste recycling for carbon smart circular bioeconomy and sustainable development: A review

The development of sustainable and low carbon impact processes for a suitable management of waste and by-products coming from different factors of the industrial value chain like agricultural, forestry and food processing industries. Implementing this will helps to avoid the negative environmental impact and global warming. The application of the circular bioeconomy (CB) and the circular economic models have been shown to be a great opportunity for facing the waste and by-products issues by bringing sustainable processing systems which allow to the value chains be more responsible and resilient. In addition, biorefinery approach coupled to CB context could offer different solution and insights to conquer the current challenges related to decrease the fossil fuel dependency as well as increase efficiency of resource recovery and processing cost of the industrial residues. It is worth to remark the important role that the biotechnological processes such as fermentative, digestive and enzymatic conversions play for an effective waste management and carbon neutrality.

The Novel Approach of Catalytic Interesterification, Hydrolysis and Transesterification of Pongamia pinnata Oil

The properties of biodiesel are completely dependent on the fatty acid profile of feedstock oils. Several feedstocks are not in use for biodiesel production because of the presence of unsuitable fatty acids in their oils. The present study was conducted to overcome this problem by the utilization of interesterification and hydrolysis processes. The present study reports biodiesel with much better cold flow properties than previous studies. Fatty acids present in Pongamia pinnata oil were optimized via interesterification and hydrolysis treatment of feedstock prior to alkali-catalyzed transesterification. The physiochemical properties of fuel were evaluated by standard test methods and the results were compared with EN 14214 and ASTM D6751 standards. Biodiesel composition was analyzed by a gas chromatographic analysis. The density, saponification and iodine values of the biodiesel derived from treated and non-treated oil were found to be within the range recommended by the international fuel standards. The acid values of biodiesel produced from non-treated and treated fractions were high (0.7–0.8 mg of KOH/g of oil), as compared to the biodiesel produced from non-treated and treated pure oil. The cloud points and pour points of biodiesel produced from hydrolyzed and interesterified oil were in the range of (8.1 to −9.6 °C) and (2.03 to −12.5 °C), respectively, while those of non-treated oil were in the range of (13.37 to −1.53 °C). These results indicate that treatments of oil specifically improved the low-temperature properties of biodiesel.

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels

Combating climate change and ensuring energy supply to a rapidly growing global population has highlighted the need to replace petroleum fuels with clean, and sustainable renewable fuels. Biofuels offer a solution to safeguard energy security with reduced ecological footprint and process economics. Over the past years, lignocellulosic biomass has become the most preferred raw material for the production of biofuels, such as fuel, alcohol, biodiesel, and biohydrogen. However, the cost-effective conversion of lignocellulose into biofuels remains an unsolved challenge at the industrial scale. Recently, intensive efforts have been made in lignocellulose feedstock and microbial engineering to address this problem. By improving the biological pathways leading to the polysaccharide, lignin, and lipid biosynthesis, limited success has been achieved, and still needs to improve sustainable biofuel production. Impressive success is being achieved by the retouring metabolic pathways of different microbial hosts. Several robust phenotypes, mostly from bacteria and yeast domains, have been successfully constructed with improved substrate spectrum, product yield and sturdiness against hydrolysate toxins. Cyanobacteria is also being explored for metabolic advancement in recent years, however, it also remained underdeveloped to generate commercialized biofuels. The bacterium Escherichia coli and yeast Saccharomyces cerevisiae strains are also being engineered to have cell surfaces displaying hydrolytic enzymes, which holds much promise for near-term scale-up and biorefinery use. Looking forward, future advances to achieve economically feasible production of lignocellulosic-based biofuels with special focus on designing more efficient metabolic pathways coupled with screening, and engineering of novel enzymes.

Phosphate solubilizing bacteria enhanced growth, oil yield, antioxidant properties and biodiesel quality of Kasumbha

Biodiesel is considered as a potential alternative energy source, but problem exists with the quantity and quality of feedstock used for it. To improve the feedstock quality of biodiesel, a field experiment was conducted under natural conditions. Cultivar Thori of kasumbha was used in the experiment. Commercialized biofertilizers were applied at the rate of 20 kg per acre and chemical fertilizer (diammonium phosphate) was applied as half dose (15 kg/ha). Results indicated that number of leaf plant^-1, leaf area, number of seeds capitulum^-1 was significantly increased by biofertilizer treatment alone (BF) and combine treatment of biofertilizer and chemical fertilizer (BFCF). Agronomic traits such as plant height, no. of branches of a plant, no. of capitulum/plant was improved significantly by BF treatment over the control. Maximum 1000 seed weight (41%) and seed yield (23%) were recorded in half dose of chemical fertilizers treatment (CFH). Seed oil content and seed phenolics were significantly improved by BF and CF treatments while maximum biodiesel yield was recorded by BF treatment. Maximum oleic acid was recorded by BF treatment while other fatty acids being maximum in control except linoleic acid in BFCF treatment. Results for specific gravity were non-significant while acid value and free fatty acid contents were substantially reduced by BF treatment as compared to other treatments. Maximum value of iodine number was recorded in BFCF treatment while tocopherol contents were improved by BF treatment. It is inferred that biofertilizer treatment alone perform better as compared to other treatments and 50% chemical fertilizer can be replaced using biofertilizer which is a good approach for sustainable environmental-friendly agriculture.

Key ingredients and recycling strategy of personal protective equipment (PPE): Towards sustainable solution for the COVID-19 like pandemics

The COVID-19 pandemic has intensified the complications of plastic trash management and disposal. The current situation of living in fear of transmission of the COVID-19 virus has further transformed our behavioural models, such as regularly using personal protective equipment (PPE) kits and single-use applications for day to day needs etc. It has been estimated that with the passage of the coronavirus epidemic every month, there is expected use of 200 billion pieces of single-use facemasks and gloves. PPE are well established now as life-saving items for medicinal specialists to stay safe through the COVID-19 pandemic. Different processes such as glycolysis, hydrogenation, aminolysis, hydrolysis, pyrolysis, and gasification are now working on finding advanced technologies to transfer waste PPE into value-added products. Here, in this article, we have discussed the recycling strategies of PPE, important components (such as medical gloves, gowns, masks & respirators and other face and eye protection) and the raw materials used in PPE kits. Further, the value addition methods to recycling the PPE kits, chemical & apparatus used in recycling and recycling components into value-added products. Finally, the biorenewable materials in PPE for textiles components have been discussed along with concluded remarks.

Heterogeneous base catalysts: Synthesis and application for biodiesel production - A review

Recently, much research has been carried out to find a suitable catalyst for the transesterification process during biodiesel production where heterogeneous catalysts play a crucial role. As homogenous catalysts present drawbacks such as slow reaction rate, high-cost due to the use of food grade oils, problems associated with separation process, and environmental pollution, heterogenous catalysts are more preferred. Animal shells and bones are the biowastes suitably calcined for the synthesis of heterogenous base catalyst. The catalysts synthesized using organic wastes are environmentally friendly, and cost-effective. The present review is dedicated to synthesis of heterogeneous basic catalysts from the natural resources or biowastes in biodiesel production through transesterification of oils. Use of calcined catalysts for converting potential feedstocks (vegetable oils and animal fat) into biodiesel/FAME is effective and safe, and the yield could be improved over 98%. There is a vast scope for biowaste-derived catalysts in green production of biofuel.