Comparative study of different catalysts mediated FAME conversion from macroalga Padina tetrastromatica biomass and hydrothermal liquefaction facilitated bio-oil production

Improved catalytic stability of immobilized Candida antarctica lipase B on macroporous resin with organic polymer coating for biodiesel production

Lipase is one of the most widely studied and applied biocatalysts. Due to the high enzyme leakage rate of the immobilization method of physical adsorption, we propose a new lipase immobilization method, based on the combination of macroporous resin adsorption and organic polymer coating. The immobilized Candida antarctica lipase B (CALB@resin-CAB) was prepared by combining the macroporous resin adsorption with cellulose acetate butyrate coating, and its structure was characterized by various analytic methods. Immobilized lipase was applied for biodiesel production using acidified palm oil as the starting material, the conversion rate achieved as high as 98.5% in two steps. Furthermore, the immobilized lipase displayed satisfactory stability and reusability in biodiesel production. When the aforementioned reaction was carried out in a continuous flow packed bed system, the yield of biodiesel was 94.8% and space-time yield was 2.88 g/(mL∙h). The immobilized lipase CALB@resin-CAB showed high catalytic activity and stability, which has good potential for industrial application in the field of oil processing.

Biobased heterogeneous renewable catalysts: Production technologies, innovations, biodiesel applications and circular bioeconomy

The growing population and waste biomass accumulation are leading to increased environmental pollution and climate change. Waste biomass comprising of nutrient rich components has promising potential to produce value-added products for sustainable environmental solutions. This review explores the critical role of bio-based heterogeneous catalysts in enabling sustainable waste biomass utilization. In industrial chemical transformations, over 95% involve catalysts, with more than 90% being heterogeneous systems, prized for their robustness, ease of product separation, and reusability. Bio-based heterogeneous catalysts address the pressing need for sustainable waste biomass management, allowing the conversion of diverse waste biomasses into biodiesel as valuable products. Research on these catalysts, particularly for biodiesel production, has shown yields exceeding 90% with enhanced catalyst reusability. This surge in research is evident from the increasing number of published articles, notably in 2022 and 2023, highlighting growing interest and importance in the scientific community. The synthesis of these catalysts is examined, including novel approaches and techniques to enhance their efficiency, selectivity, and stability. The challenges with their feasible solutions of heterogeneous catalysts in catalyst-based processes are addressed. Altogether, this review underscores the immense potential of bio-based heterogeneous catalysts in sustainable waste biomass utilization, aligning with resource efficiency and environmental conservation goals while offering distinct insights and perspectives on the latest innovations in the field.

Biodiesel production and exploring properties of Datura stramonium L. oil with its optimization using combined approaches-Taguchi, grey relational analysis, and response surface methodology

Biodiesel production through the synthesis of Datura stramonium L. oil is studied to explore the most efficient approaches to suggest an alternate feedstock for biodiesel production. The main objective of this work is to optimize the process variables of biodiesel synthesis by using some statistical approach (Taguchi method, grey relational analysis (GRA), and response surface methodology (RSM) analyzing three parameters, i.e., alcohol-to-oil molar ratio, catalyst (NaOH) concentration, and process temperature for achieving maximum biodiesel derived from Datura stramonium L. oil. The transesterification process is applied by using an ultrasonic-assisted technique. Grey relational analysis (GRA) was successfully applied with the Taguchi method resulting in the optimum combination of A2B1C1. Based on the findings, the best operating conditions for transesterifying are attained with the RSM approach consisting of a 5.697:1 molar ratio (level 2), 0.3 (wt.%) NaOH concentration (level 1), and 70 °C process temperature (level 1). With a value of 87.02%, these ideal operating conditions produce the maximum yield as compared to grey relational analysis (GRA) yields 83.99%. The obtained results have been verified through the characterization of oil and biodiesel as well. Also, the fuel qualities of DSL biodiesel were identified and assessed. DSL oil was found 137.6 degrees of unsaturation during fatty acid profile analysis. DSL biodiesel was found the best kinematic viscosity (4.2 mm2/s) and acid value (0.49) when compared to Karanja and palm biodiesel. D. stramonium L. was recognized as a suitable species for biodiesel feedstock according to the findings.

Red seaweed biorefinery: The influence of sequential extractions on the functional properties of extracted agars and porphyrans

Red seaweeds are exploited for their hydrocolloids, but other fractions are usually overlooked. In a novel approach, this study aimed to evaluate cold-water (CWE), ethanolic (EE), and alkaline (SE) extractions, alone and in sequence, to simultaneously: i) decrease the hydrocolloid extraction waste (valorizing bioactive side-streams and/or increasing extraction yield); and ii) increase the hydrocolloids' texturizing properties. It is the first time these extractions' synergetic and/or antagonistic effects will be accessed. For Porphyra dioica, a combination of CWE and EE was optimal: a positive influence on the melting temperature (increasing 5 °C to 74 °C) and sulphate content (a 3-fold reduction to 5 %) was observed, compared to a direct porphyran extraction. The same was observed for Gracilaria vermiculophyla, recovering two additional bioactive fractions without impacting the hydrocolloid's extraction (agar with 220 g/cm2 gelling strength and 14 % yield was obtained). The sequential use of CWE, EE, and SE was the most beneficial in Gelidium corneum processing: it enhanced agar's texturizing capacity (reaching 1150 g/cm2, a 1.5-fold increase when compared to a direct extraction), without affecting its 22 % yield or over 88 % purity. Ultimately, these findings clarified the effects of cascading biorefinery approaches from red seaweeds and their pertinence.

Hydrothermal Liquefaction: How the Holistic Approach by Nature Will Help Solve the Environmental Conundrum

Hydrothermal liquefaction (HTL) represents a beacon of scientific innovation, which unlocks nature's alchemical wonders while reshaping the waste-to-energy platform. This transformative technology offers sustainable solutions for converting a variety of waste materials to valuable energy products and chemicals-thus addressing environmental concerns, inefficiencies, and high costs associated with conventional waste-management practices. By operating under high temperature and pressure conditions, HTL efficiently reduces waste volume, mitigates harmful pollutant release, and extracts valuable energy from organic waste materials. This comprehensive review delves into the intricacies of the HTL process and explores its applications. Key process parameters, diverse feedstocks, various reactor designs, and recent advancements in HTL technology are thoroughly discussed. Diverse applications of HTL products are examined, and their economic viability toward integration in the market is assessed. Knowledge gaps and opportunities for further exploration are accordingly identified, with a focus on optimizing and scaling up the HTL process for commercial applications. In conclusion, HTL holds great promise as a sustainable technology for waste management, chemical synthesis, and energy production, thus making a significant contribution to a more sustainable future. Its potential to foster a circular economy and its versatility in producing valuable products underscore its transformative role in shaping a more sustainable world.

Multifunctional catalyst-assisted sustainable reformation of lignocellulosic biomass into environmentally friendly biofuel and value-added chemicals

Rapid urbanization is increasing the world's energy demand, making it necessary to develop alternative energy sources. These growing energy needs can be met by the efficient energy conversion of biomass, which can be done by various means. The use of effective catalysts to transform different types of biomasses will be a paradigm change on the road to the worldwide goal of economic sustainability and environmental protection. The development of alternative energy from biomass is not easy, due to the uneven and complex components present in lignocellulose; accordingly, the majority of biomass is currently processed as waste. The problems may be overcome by the design of multifunctional catalysts, offering adequate control over product selectivity and substrate activation. Hence, this review describes recent developments involving various catalysts such as metallic oxides, supported metal or composite metal oxides, char-based and carbon-based substances, metal carbides and zeolites, with reference to the catalytic conversion of biomass including cellulose, hemicellulose, biomass tar, lignin and their derivative compounds into useful products, including bio-oil, gases, hydrocarbons, and fuels. The main aim is to provide an overview of the latest work on the use of catalysts for successful conversion of biomass. The review ends with conclusions and suggestions for future research, which will assist researchers in utilizing these catalysts for the safe conversion of biomass into valuable chemicals and other products.

From waste-activated sludge to algae: a self-reliant cultivation process in photoreactors using saline conditions

In this study, microalgae-bacteria (MB) systems using saline conditions (3 and 5% salinity) were built in order to use waste-activated sludge (AS) as raw material for cultivating lipid-rich microalgae. Algae were observed to be flourishing in 60 days of operation, which totally used the N and P released from the sludge biomass. A prominent improvement of lipid content in MB consortia was obtained under algae growth and salinity stimulation, which occupied 119-136 mg/g-SS rather than a low content of 12.1 mg/g-SS in AS. Lipid enrichment also brought a 3.1-3.3 times total heat release (THR) in the MB biomass. The marine spherical algae Porphyridium, as well as filamentous Geitlerinema, Nodularia, Leptolyngbya were found to be the main lipid producers and self-flocculated to 23.0% (R1) and 33.5% (R2) volume under the effect of residue EPS. This study had a big meaning in not only waste sludge reduction but also in manufacturing useful bioenergy products.

Investigations on evaluation of marine macroalgae Dictyota bartayresiana oil for industrial scale production of biodiesel through technoeconomic analysis

The investigation on utilizing macroalgae for industrial scale biodiesel production is an imperative action needed for commercialization. In the present research work, the biooil from marine macroalgae Dictyota bartayresiana was used for biodiesel production using calcium oxide nanocatalyst synthesized using waste collected from building demolition site. The optimization results obtained were the calcination temperature 573 °C, concentration of catalyst 5.62%, methanol to oil molar ratio 14.36:1, temperature 55.7 °C and time 67.57 min for the transesterification with the biodiesel yield of 89.6%. The techno-economic aspects of biodiesel production were investigated for 20 MT/batch. The return on investment and internal rate of return from the biodiesel production plant was found to be 25.39% and 31.13% respectively. The plant payback period was about 3.94 years with a positive NPV value of about 14,053,000 $/yr. Thus, Dictyota bartayresiana biomass can be efficiently used for the sustainable production of biodiesel.

Rapeseed Oil-based Biodiesel as Lubricant: Frictional Force and Tribological Analysis

Lubrication is necessary to minimise the frictional impact created during the running of a vehicle since it increases wear and friction among the parts in contact. Wear and friction shorten the component's life, decrease its dependability, and raise maintenance costs. The current study uses a tribo tester to examine the friction and wear properties of rapeseed biodiesel at fixed parameters. The investigated lubricants included B0 (diesel), B100 (biodiesel), and four distinct blends of biodiesel: B15, B30, B45, and B60. Analysis was done for one hour at ambient temperature with a standard load of 140 N at a speed of 1000 rpm. The outcome showed that as the concentration of biodiesel augmented, friction and wear scar get reduced. The aluminium pin wear in B100 appeared 16% less than that in diesel. Also, the presence of esters and fatty acids during Fourier transform infrared analysis of biodiesel contributes more to its possibilities as a lubricant.