Rapid biodiesel synthesis from waste pepper seeds without lipid isolation step

Emerging innovations for sustainable production of bioethanol and other mercantile products from circular economy perspective

Biogenic municipal solid waste (BMSW) and food waste (FW) with high energy density are ready to tap renewable resources for industrial scale ethanol refinery foreseen for establishing bio-based society. Circular economy has occupied limelight in the domain of renewable energy and sustainable chemicals production. The present review highlights the importance of BMSW/FW as newer feed reserves that can cater as parent molecules for an array of high-visibility industrial products along with bioethanol upon implementing a judicious closed-cascade mass-flow mechanism enabling ultimate feed and waste stream valorisation. Though these organics are attractive resources their true potential for energy production has not been quantified yet owing to their heterogeneous composition and associated technical challenges thus pushing waste refinery and industrial symbiosis concepts to backseat. To accelerate this industrial vision, the novel bioprocessing strategies for enhanced and low-cost production of bioethanol from BMSW/FW along with other commercially imperative product portfolio have been discussed.

Catalytic pyrolysis of swine manure using CO2 and steel slag

Pyrolysis of swine manure (SM) was conducted as a case study to establish an environmentally sound management of livestock manure. To build a more renewable pyrolysis platform for SM, this study selected carbon dioxide (CO₂) as the reaction medium. In addition, CO₂ was used in pyrolysis of SM to restrict the formation of toxic compounds, such as benzene derivatives and polycyclic aromatic hydrocarbons (PAHs). A series of thermo-gravimetric analysis (TGA) tests was done to understand the thermolysis of SM in the CO₂ environment. The TGA tests elucidated no occurrence of heterogeneous reactions between the SM sample and the CO₂. Moreover, the TGA tests of SM suggested that SM contains more volatile matter (VM) than lignocellulosic biomass. Non-catalytic transesterification of SM lipids confirmed that the dried SM sample contained 8.85 ± 0.05 wt% of lipids. This study also confirmed that the mechanistic role of CO₂ was realized through the gas phase reactions between volatile pyrolysates evolved from the thermolysis of SM and CO₂. In summary, CO₂ donates O, enhancing the generation of CO through homogeneous reactions. In parallel, this study confirmed that CO₂ suppress dehydrogenation. Therefore, the identified gas phase reactions between volatile pyrolysates and CO₂ led to the compositional modifications in the condensable pyrolysates. However, such mechanistic features arising from CO₂ only initiated at ≥520 °C. To expedite the reaction kinetics of the homogeneous reaction triggered by CO₂, steel slag (SS) was used as a catalyst. Hence, the reaction kinetics associated with the mechanistic role of CO₂ were substantially enhanced (up to 80%) when SS was used as a catalyst. Therefore, all experimental findings strongly suggest that CO₂ can be utilized as a raw material in a thermo-chemical process. More importantly, all observations suggest that CO₂ lopping can also be achieved in a thermo-chemical process. Lastly, this study shows that the high Cu content in SM was effectively immobilized through pyrolysis. Conclusively, this study experimentally proved that CO₂ could be promising for restricting the formation of toxic pollutant in the thermo-chemical treatment in that CO₂ offers an innovative and strategic means for controlling the ratio of C to H. Note that aromaticity and toxicity of chemical compounds are highly contingent on the ratio of C to H.

Conversion of food and kitchen waste to value-added products

Food and kitchen waste - omnipresent in every corner of the world serve as an excellent source of value added products owing to high organic content. Regardless of existence of various traditional methods of land filling or biogas production used to harness food waste energy, effective conversion of food to valuable resources is often challenged by its heterogenous nature and high moisture content. The current paper tries to lay down the prospects and consequences associated with food waste management. The various social, economical and environmental concerns associated with food waste management especially in terms of green house gas emission and extended rate of leachate generation also has been discussed. The difficulties in proper collection, storage and bioconversion of food waste to valuable by-products are pointed as a big hurdle in proper waste management. Finally, the wide array of value added products developed from food waste after pretreatment are also enlisted to emphasis the prospects of food waste management.

Biodiesel synthesis from fish waste via thermally-induced transesterification using clay as porous material

The valorization of organic waste through biodiesel synthesis was investigated to explore the concept of hazardous waste-to-energy. Fish waste (mackerel waste) was chosen as a case study because of the growing concern regarding the treatment of food waste, which is potentially hazardous to the environment. This study focused on the thermally-induced transesterification of fish waste for the production of biodiesel (i.e., fatty acid methyl esters (FAMEs)). This process requires a porous material that allows for the collision between reactants (fish waste and methanol) to increase inside its pores at high temperatures. Therefore, commercial clay (montmorillonite) was used as the porous material in this study. The optimal temperature for the thermally-induced transesterification of unpurified mackerel oil was 380 °C, and the FAME recovery reached up to ˜72 wt.%. This study also proved that thermal cracking of polyunsaturated FAME species was initiated at temperatures ≥390 °C, and that fish waste is a promising feedstock for biodiesel when it is produced via thermally-induced transesterification over clay as a porous material.

WITHDRAWN: An integrated approach towards sustainable wastewater treatment and biofuel production: A phytotechnological study on defatted residual seed biomass of Datura stramonium L

Available online 1 March 2019. This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

WITHDRAWN: A combinatorial bioinnovative approach integrating synthetic dye bioremediation and bioenergy production using waste pepper seed biomass

A combinatorial study integrating synthetic dye bioremediation and biodiesel production using discarded pepper seed biomass was performed for a cleaner and more sustainable environment/energy in the present work. The vegetal oil was extracted from the pepper seed biomass and the defatted residual biomass was mainly investigated as a sustainable green generation alternative biosorbent source for the treatment of colored aqueous effluents. To test the wastewater cleaning ability of biosorbent, basic red 46 was selected as a common harmful model synthetic dye. The kinetic, equilibrium and thermodynamic modeling studies were performed to elucidate the dye biosorption behavior of biosorbent. Besides, the performance of dye bioremediation system was evaluated using the kinetic modeling parameters, and for large scale dye purification applications, a single-stage batch bioreactor system was designed using the mathematical modeling data. The operating conditions significantly affected the biosorption process. The pseudo-second-order and Freundlich models provided the best fit to the kinetic and isotherm data, respectively. The thermodynamic studies showed that the dye biosorption was a feasible and spontaneous process. The maximum dye biosorption capacity of biosorbent based on Langmuir model was predicted as 82.019 mg g-1. As compared many other biosorbents reported in literature for the same contaminant, this high value revealed a great potential of biosorbent for the dye removal from aqueous medium. Thus, the present study showed that the discarded pepper seed biomass could be employed as a highly efficient as well as cost-effective material for both dye bioremediation and biodiesel production in a sustainable manner.

Microalgae as feedstock for biodiesel production under ultrasound treatment - A review

The application of ultrasound in biodiesel production has recently emerged as a novel technology. Ultrasound treatment enhances the mass transfer characteristics leading to the increased reaction rate with short reaction time and potentially reduces the production cost. In this review, application of ultrasound-assisted biodiesel production using acid, base and enzyme catalysts is presented. A critical assessment of the current status of ultrasound in biodiesel production was discussed with the emphasis on using ultrasound for efficient microalgae biodiesel production. The ultrasound in the biodiesel production enhances the emulsification of immiscible liquid reactant by microturbulence generated by cavitation bubbles. The major benefit of the ultrasound-assisted biodiesel production is a reduction in reaction time. Several different methods have been discussed to improve the biodiesel production. Overall, this review focuses on the current understanding of the application of ultrasound in biodiesel production from microalgae and to provide insights into future developments.

Biodiesel synthesis using chicken manure biochar and waste cooking oil

This study laid an emphasis on the possible employment of biochar generated from pyrolysis of chicken manure to establish a green platform for producing biodiesel. To this end, the pseudo-catalytic transesterification reaction using chicken manure biochar and waste cooking oil was investigated. Compared with a commercial porous material (SiO₂), chicken manure biochar generated from 350°C showed better performance, resulting in 95.6% of the FAME yield at 350°C. The Ca species in chicken manure biochar imparted strong catalytic capability by providing the basicity for transesterification. The identified catalytic effect also led to the thermal cracking of unsaturated FAMEs, which decreased the overall FAME yield. For example, 40-60% of converted FAMEs were thermally degraded. To avoid undesirable thermal cracking arising from the high content of the Ca species in chicken manure biochar, the fabrication of chicken manure biochar at temperatures ≥350°C was highly recommended.