Leftover Biomass Research Articles

Coupling of biochar and silicon for Phyto-management of Cd contaminated soil using Brachiariamutica

Contamination of soil with heavy metals is a threatening global environmental problem. With increasing urbanization, it is very important to design economical and environment-friendly mitigation measures to have pollutant free soil. Phytoremediation is an advancing technique to extract pollutants from soil to achieve eco-sustainability. This study aimed to investigate the combined impact of biochar and silicon on growth attributes of Brachiaria mutica grown in cadmium (Cd) contaminated soil. The biochar was prepared by co-pyrolysis of agricultural left-over biomass (rice husk, bamboo leaves and corn cob in a 1:1:1 ratio) and physio-chemical characters were studied by FTIR, SEM-EDX and proximate analysis. A pot study was conducted to evaluate the potency of biochar and silicon in lowering the Cd uptake by para grass grown under Cd spiked soil. Total 8 treatments were planned by taking 1 % and 2 % biochar with 0.01 % and 0.02 % silicon. The results have shown that treatment 8 (2 % biochar and 0.02 % silicon) exhibited maximum improvement in growth parameters such as shoot length by 2.64-fold and root length by 44.9 %, along with improving the antioxidant defense system of Para grass (CAT by 2-fold and POD by 56.4 %). Application of treatment 8 also decreased Cd concentration in the shoot and root by 48.8 % and 47.4 %, respectively. Treatment 8 was most effective in reducing CaCl2 extractable Cd in soil up to 56.1 %. Based on this data, treatment 8 was most effectual in suppressing Cd stress. Biochar produced from other agricultural waste material along with Si as inorganic amendment can be used to immobilize other toxic heavy metals at field level. Heavy metals immobilization potential of Si and biochar can be tested by harvesting other grasses and oil seed crop species.

Decrypting solvent‐free microwave as a dual green extraction: studying simultaneous extraction of essential oil and phenolics from the same biomass – valorization and outperforming traditional approaches

AbstractBACKGROUNDThe current research work focuses on the sustainable utilization of plant biomass so that two separate classes of phytocompounds (volatile and non‐volatile principles) can be extracted from the same biomass simultaneously. The hydro‐diffusion and gravity variant of solvent‐free microwave‐based extraction (MHG‐SFME) was attempted for the extraction of Piper betle L. essential oil (PBEO).RESULTSThe threat of milky emulsion has been exemplified for the first time which is likely to occur when the biomass temperature exceeds a critical value (85 °C). A microwave power level of 255 W with 25 min of extraction time produced PBEO with eugenol content 123% more than that obtained with steam distillation (SD). The said optimal MHG‐SFME conditions returned PBEO with the highest phenolic (20.8 mg GAE g−1 of oil) and eugenol (657.57 μg g−1) contents. PBEO showed better thermal behavior when compared to the EO obtained from SD.CONCLUSIONThe proposed method was capable of retaining non‐volatile principles, as the retention of total phenolics in biomass after MHG‐SFME was found to be 95%, indicating reusability of the biomass for the extraction of non‐volatile principles. In contrast, the retention factor of phenolics content for SD was found to be 17.7% only. Real‐time evidence in the form of chemo‐microscopy and scanning electron microscopy was generated to understand the retention of phenolics and ultrastructural changes upon microwave exposure. Complete glandular rupture was evident in the biomass subjected to MHG‐SFME while the oil glands appeared squeezed for the biomass which underwent SD. Complete profiling of phenolics and flavonoid principles of the leftover biomass was carried out. © 2024 Society of Chemical Industry (SCI).

Cyanobacteria as an eco-friendly bioresource for EPS production with crack healing capacity in concrete

Cyanobacteria, alike microalgae, are photosynthetic microorganisms found in different environmental conditions. These photosynthetic bacteria are also considered promising solutions for cracking problem in concretes. These photosynthetic organisms precipitate CaCO3 crystals in concrete microcracks and pores, thus sealing the cracks and increasing the strength gain of the concrete blocks. Cyanobacteria Lyngbya sp., Phormidium sp., and microalgae Chlorella vulgaris were studied initially. Lyngbya sp., Phormidium sp., and Chlorella vulgaris have the additional property of secreting the exopolysaccharide (EPS). EPSs are an important class of biopolymers with great ecological importance. Because of their high charge density and capacity to act as mineralization nucleation sites, cyanobacterial exopolysaccharides are currently receiving more attention. Using the three strains stated above, this study investigates the impact of physiochemical factors on biomass concentration and exopolysaccharide synthesis and creates mathematical models. Using Central Composite Design (CCD), it is possible to study the interactions between the many parameters, including nitrate concentration, starting media pH, light intensity, and temperature. The biochemical characteristics of the leftover biomass are assessed after exopolysaccharide extraction, and because of its high carbohydrate and fat content, it can be used to produce biofuel. The study of checking the microbial crack healing capacity and strength gain of the concrete using these three cyanobacterial strains is being studied. Based on the outcome, the best species was chosen. Further microstructural analyses, such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to support the calcium carbonate precipitation.

Microwave irradiation pretreated fermentation of bioethanol production from Chlorella vulgaris Biomasses: Comparative analysis of response surface methodology and artificial neural network techniques

Bioethanol is a promising biofuel for replacing gasoline due to its sustainability. This work uses microwave irradiation and acid hydrolysis to produce bioethanol from Chlorella vulgaris. The hydrolysis procedure used 1%–3% sulfuric acid (H2SO4). The maximum output of reducing sugar was 6.773 g/L after 5 min of irradiation. This study used RSM and ANN to optimize bioethanol production. The study predicted bioethanol yield using three factors: fermentation duration (12–36 h), temperature (28–32 °C), and inoculum concentration (0.5–1.5 g/L). The highest bioethanol yield was achieved using fermentation conditions of 36 h, 30 °C temperature, and 1.5 g/L inoculum concentration. The ANN model predicted the best ethanol output compared to the RSM model. The leftover biomass from biofuel synthesis was characterized for its potential for other energy production. The current study examined the feasibility of employing biomass in an environmentally sustainable manner to enhance the production of biofuels.

Effect of Carbon Nanoparticles in Biochar and Sulphur as a Foliar Spray on Onion Plants: A New Orientation

Biochar contains raw carbon nanoparticles. Water-soluble dried carbon powder nanoparticles (wsCNPs) isolated from leftover biomass (waste stems and roots) in agricultural land can enhance the overall growth rate of onion (Allium cepa L.) plants. Field experiments conducted in 2017–2018 and 2018–2019 aimed to evaluate the effect of wsCNPs and sulfur as a foliar spray on vegetative growth, yield, and some nutritional values of onion plants. The biochar used in the study solution, namely, wsCNPs, was applied at 300, 400, and 500 mg/L incorporated with three levels of 2.5, 3.5, and 4.5 g/L of sulfur (Thiovit, 80%) as a foliar spray. Results indicated that treated plants with all levels of wsCNPs and sulfur had significantly higher values of vegetative growth parameters, photosynthetic pigments, yield, bulb quality, and phytochemical compounds compared with untreated plants. Using the highest foliar spray level of wsCNPs and sulfur obtained significant results for all evaluated characteristics among other levels. This increment was more pronounced when wsCNPs and sulfur were combined, indicating that spraying is a useful agriculture and eco-friendly practice for sustainable crop production.

A review on unit operations, challenges, opportunities, and strategies to improve algal based biodiesel and biorefinery

Globally, the demand for energy is increasing with an emphasis on green fuels for a sustainable future. As the urge for alternative fuels is accelerating, microalgae have emerged as a promising source that can not only produce high lipid but many other platform chemicals. Moreover, it is a better alternative in comparison to conventional feedstock due to yearlong easy and mass cultivation, carbon fixation, and value-added products extraction. To date, numerous studies have been done to elucidate these organisms for large-scale fuel production. However, enhancing the lipid synthesis rate and reducing the production cost still remain a major bottleneck for its economic viability. Therefore, this study compiles information on algae-based biodiesel production with an emphasis on its unit operations from strain selection to biofuel production. Additionally, strategies to enhance lipid accumulation by incorporating genetic, and metabolic engineering and the use of leftover biomass for harnessing bio-products have been discussed. Besides, implementing a biorefinery for extracting oil followed by utilizing leftover biomass to generate value-added products such as nanoparticles, biofertilizers, biochar, and biopharmaceuticals has also been discussed.

Phycoremediation of Dyes: An Overview on Mechanism, Challenges, and Prospects

Dyes are major water pollutants as they show hazardous effects towards humans and aquatic environment. Various physical and chemical methods are used for the remediation of dyes but in the last few years, focus has been shifted towards the modern technique of remediation. Biological techniques have been exploited and utilized for the remediation of dyes as they are more sustainable, simple, and lead to the development of green technology. This review presents the different microalgal strains which are used for the remediation of dyes. It is seen that alone algal bioremediation of dyes is not an efficient and economical process. To overcome this challenge, a more advanced system, phyconanoremediation of dyes is also discussed briefly. Algal nanoparticles can achieve more remediation within few hours which makes this technique more efficient. Moreover, to make this more economical, a strategy to use the left-over biomass to produce valuable products like bioelectricity, pigments, biofuel and other medical products is also introduced. Later, challenges and opportunities are also discussed to make algal bioremediation more effective, sustainable, green, and clean technology.

Prospects and Perspective of Essential Oil-Bearing Plants: A Case Study of Lemongrass Cultivation in Fallow Land and Chemoprospecting of Essential Oil

India has vast uncultivated areas such as marginalized lands, barren lands, unused land spaces, wastelands, side bunds, and areas having menace of wild/grazing animals. Surprisingly, the uncultivated area is progressively increasing due to various factors. Nevertheless, the unused lands can be utilized for beneficial purposes. Therefore, a case study was undertaken to cultivate lemongrass in uncultivated land and the cost-benefit analysis indicated that it could be a source of decent livelihood generation and an additional income source for village communities. Further, simple steps of essential oil isolation and its fractionation to isolate fine chemicals and enriched fractions, and inclusive utilization of the leftover biomass are extremely useful for enterprise development and employment generation in the hilly and rural areas. Apart from tangible benefits, the approach is also useful for reclamation of uncultivated lands, mitigation of climate change, soil health improvement, reducing the menace of invasive species, and in line with sustainable development goals to achieve a better future for all. The case study could be a model to benefit each member of society and improve the overall economy and environment.

Study of anti-diabetic, beta-carotene-bleaching inhibiting and iron chelating properties of Carissa opaca root extracts

Degenerative diseases diabetes and oxidative stress constitute a major health concern worldwide. Medicinal plants are expected to provide effective and affordable remedies. The present research explored antidiabetic and antioxidant potential of extracts of Carissa opaca roots. Methanolic extract (ME) was prepared through maceration. Its fractions were obtained, sequentially, in hexane, chloroform, ethyl acetate and n-butanol. An aqueous decoction (AD) of the finely ground roots was obtained by boiling in distilled water. The leftover biomass with methanol was boiled in water to obtain biomass aqueous decoction (BAD). The extracts and fractions showed considerable porcine pancreatic α-amylase inhibitory activity with IC50 in the range of 5.38-7.12 mg/mL while acarbose had 0.31 mg/mL. The iron chelating activity in terms of EC50 was 0.2939, 0.3429, 0.1876, and 0.1099 mg/mL for AD, BAD, ME, and EDTA, respectively. The EC50 of beta-carotene bleaching activity for AD, BAD, ME, and standard BHA were 4.10, 4.71, 3.48, and 2.79 mg/mL, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of AD and BAD were also considerable. In general, ethyl acetate fraction proved to be the most potent. Thus, the C. opaca roots had excellent antioxidant activity while having moderate α-amylase inhibitory potential.

Extraction and isolation of lignin from ash tree (Fraxinus exselsior) with protic ionic liquids (PILs)

Protic ionic liquids (PILs) have been considered effective solvents for the selective separation and recovery of cellulose from lignocellulosic biomass. However, PILs can also be utilized for the extraction and conversion of lignin into fuels and value-added products. The objective of this work was to study the extraction of lignin from ash tree (Fraxinus exselsior) hardwood biomass using three different PILs—pyridinium acetate, pyridinium formate [Py][For], and pyrrolidinium acetate. Fiber analysis was used to determine the biochemical composition of the left-over biomass after lignin separation. FTIR and NMR were applied to determine the structure of dissolved lignin. Additionally, the regeneration potential and recyclability of PILs were assessed. Our results demonstrate that treatment with [Py][For] at 75 °C yields the highest percentage of lignin dissolution from biomass. This indicates that PILs could be used for Kraft lignin dissolution as well as separation of lignin from raw, milled biomass.

Antimicrobial and dye degradation application of fungi-assisted silver nanoparticles and utilization of fungal retentate biomass for dye removal.

The present study utilized Aspergillus spp. for the synthesis of silver nanoparticles (AgNPs); the developed AgNPs were categorized using analytical techniques, that is, ultraviolet-visible (UV-vis) spectrophotometer, Zeta-potential, dynamic light scattering (DLS), and transmission electron microscopy (TEM). A sharp peak of 463 nm highlighted the synthesis of AgNPs; further Zeta-potential of -16 mV indicates stability of synthesized AgNPs. The TEM micrograph showed spherical and hexagonal shapes of synthesized AgNPs of 6-25 nm. The photocatalytic activity of fungal-mediated AgNPs was evaluated for degradation of reactive yellow dye in the concentration range of 20-100 mg L-1 . The results showed efficient degradation of dye using AgNPs in short span of time. For antibacterial activity, synthesized AgNPs, antibiotic, and AgNPs + antibiotic were tested. As per results, the zone of inhibition (ZOI) of AgNPs showed the values of 13 and 10 mm for Escherichia coli and Staphylococcus aureus, respectively. Further, the ZOI of penicillin highlighted the values of 18 and 17 mm for E.coli and S.aureus, respectively. When AgNPs and penicillin were used in combination, a clear synergistic effect was observed; the ZOI showed 0.49- and 0.36-fold increase in area against E.coli and S.aureus, respectively, in comparison with penicillin or AgNPs alone. Further, the leftover biomass (retentate biomass) was used to decolorize the reactive yellow dye at different initial concentration ranging from 20 to 100 mg L-1 . It was observed that 1 g L-1 retentate biomass (BR ) can effectively remove 82%-100% dye at 20 and 100 mg L-1 initial dye concentration. Results also indicated that with increase in initial reactive dye concentration from 20 to 100 mg L-1 , the decolorization capacity of retentate biomass (BR ) (at 0.2 g L-1 ) decreased from 79.2% to 32.3%. However, the use of AgNPs synthesized leftover fungal biomass can be a good option for up taking the additional dyes/contaminants, and also as leftover biomass can be utilized effectively, it can prove to be an excellent approach for environment safety. As the literature studies did not mentioned the further use of retentate biomass, the present study provides an excellent approach for further research on this aspect. PRACTITIONER POINTS: Synthesis of AgNPs from Aspergillus spp. and characterized with the help of a U.V-vis spectrophotometer, a zeta potential, DLS and TEM. The developed AgNPs were used for antibacterial and dye degradation activity. The left over (retentate) fungal biomass was used further for additional dye degradation activity.

An experimental investigation on phytoremediation performance of water lettuce (Pistia stratiotes L.) for pollutants removal from paper mill effluent.

The present study describes the phytoremediation performance of water lettuce (Pistia stratiotes L.) for physicochemical pollutants elimination from paper mill effluent (PME). For this, pot (glass aquarium) experiments were conducted using 0% (BWW: borewell water), 25%, 50%, 75%, and 100% treatments of PME under natural day/light regime. Results of the experiments showed that the highest removal of pH (10.75%), electrical conductivity (EC: 63.82%), total dissolved solids (TDS: 71.20%) biological oxygen demand (BOD: 85.03%), chemical oxygen demand (COD: 80.46%), total Kjeldahl's nitrogen (TKN: 93.03%), phosphorus (P: 85.56%), sodium (Na: 91.89%), potassium (K: 84.04%), calcium (Ca: 84.75%), and magnesium (Mg: 83.62%), most probable number (MPN: 77.63%), and standard plate count (SPC: 74.43%) was noted in 75% treatment of PME after treatment by P.stratiotes. PCA showed the best vector length for TKN, Na, and Ca. The maximum plant growth parameters including, total fresh biomass (81.30±0.28g), chlorophyll content (3.67±0.05mgg-1 f.wt), and relative growth rate (0.0051gg-1 d-1 ) was also measured in 75% PME treatment after phytoremediation experiments. The findings of this study make useful insight into the biological management of PME through plant-based pollutant eradication while leftover biomass may be used as a feedstock for low-cost bioenergy production. PRACTITIONER POINTS: Biological treatment of paper mill effluent using water lettuce is presented. Best reduction of physicochemical and microbiological pollutants was attained in 75% treatment. Maximum production of chlorophyll, plant biomass, and highest growth rate was also observed in 75% treatment.

Microalgal bio-refinery approach for utilization of Tetradesmus obliquus biomass for biodiesel production

The speedy depletion of fossil fuels demands a more sustainable and renewable source for biofuel production. In this view, one promising alternative to petroleum diesel is microalgal-biodiesel, as it can grow on non-arable land, consumes CO2 for growth and most of them can withstand extreme temperature variations. Simultaneously, microalgae are promising producers of various other biofuels, such as bioethanol, glycerol and biomaterials like pigments and carotenoids. The present study emphasizes on microalgal bio-refinery of an isolated microalgae Tetradesmus obliquus SGM19; producing biodiesel, bioethanol and glycerol. The strain exhibited high lipid (28 ± 1.2%), carbohydrate (24 ± 0.8%) and protein (42 ± 0.67%) concentrations, which makes it a promising feedstock for biofuels. The isolate was also found rich in pigments such as chlorophyll and carotenoids (with high antioxidant activity), which allows their utilization like food and pharmaceutical supplements. The biomass of T. obliquus SGM19 was subjected to lipid extraction followed by bioethanol synthesis (from the carbohydrates present in leftover biomass). The extracted lipid was transesterified to produce fatty acid methyl esters (FAME), which was characterized with GC–MS. The transesterification process was a 2-step acid-based catalyzed reaction and was optimized for reaction time, reaction temperature and oil to solvent ratio. At optimum conditions, the major components of FAME obtained from T. obliquus SGM19 were palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1) and linoleic (C18:2) acids, making it suitable to be used as biodiesel. The properties of the biodiesel produced were well within the range of the ASTM standards.

Rapid Processing of Abandoned Oil Palm Trunks into Sugars and Organic Acids by Sub-Critical Water

Abandoned oil palm trunk (OPT) is among the most abundant left-over biomass in Malaysia and is allowed to decompose naturally in the field. However, the recycling of OPT is less considered although OPT is a bioresource that has a high potential for conversion into value-added products. In this study, waste OPT was rapidly converted by hydrolysis using subcritical water (sub-CW). This work is the first attempt to explore the utilization of waste OPT based on the differences in moisture, cellulose and hemicellulose contents in the top and bottom segments, and from various ages of the waste OPT. 21- and 35-year-old OPTs were divided into top and bottom sections. The OPTs was subjected to sub-CW at a heating rate of 3.8 °C/s at various temperatures and times. The 21-year-old OPT was superior to the 35-year-old OPT for conversion into sugar and organic acid. The yield of the total sugar was between 0.41 and 0.77 kg/kg-OPT in the bottom and top sections. The excellent correlation between the sugar yield and sub-CW ion product (Kw) signified that the sub-CW facilitated the hydrolysis of hemicellulose and cellulose in the OPT. In the bottom segment, fructose had a higher yield, while in the top part glucose was dominant. Sugar degradation from the sub-CW treatment of OPT produced 0.2 kg/kg-OPT organic acids. The treatment of OPT using sub-CW showed promising results in producing sugars and organic acids.

Strategies for Fermentable Sugar Production by Using Pressurized Acid Hydrolysis for Rice Husks

This study investigated the use of leftover biomass (rice husks) as the raw material for the biotechnological production of platform chemicals and biopolymers. Following the biorefinery concept, different acid hydrolysates were studied and resulted into a wide range of treatment strategies. Chemometrics were applied throughout the procedures in multivariate experimental conditions. By using the best hydrolytic conditions of 6.0% H3PO4, 135°C (45MPa) and reaction time of 62min, 21.0g/L sugar hydrolysates were produced; by using the best hydrolytic condition of 4.5% HNO3, 135°C/35min, 16.1g/L sugar hydrolysates were produced; and with the hydrolysates use of 1.5% H2SO4 and 1.5% HCl, 135°C/62min, 18.2 and 17.8g/L sugar hydrolysates were produced, respectively. The highest productivity, in terms of fermentable sugars, reached 68% of integral cellulose/hemicellulose fraction and surpassed those found in the literature, with regard to the processing of rice husks, by considering just one step process. Sulfuric hydrolysate, detoxified with active carbon, was used to prove this proposal viability, resulting in a fermentation substrate for A. terreus (ATCC10020) and R. radiobacter (LMG196) strains (natural producers of bioproducts), which certified the feasibility of the proposal. The production of fermentable sugars from leftover biomass should encourage a search for new bioconversion routes, which can result in economic and environmental benefits and a spread of knowledge.

An innovative approach for the biotechnological production of succinoglycan from rice husks

Rice husk (RH) was submitted to ozonation followed by pressurized acid hydrolysis with the aim of reducing the lignocellulosic recalcitrance and freeing the fermentable monosaccharides from cellulose and hemicellulose. The hydrolysate was then detoxified and used as a fermentative substrate for the production of succinoglycan biopolymer, which is an exopolysaccharide. The use of pH 7.0, and 25% RH (w v−1) solution, and the effects of ozonization for 60 min (1.5 g h-1 de O3), made the lignocellulosic matrix more susceptible to subsequent pressurized acid hydrolysis (2.5% H2SO4w v−1, 45 min treatment, 145 °C), and produced up to 16.1 g sugars L-1. Detoxification with activated carbon (4.0% v v-1, 60 min, 80 °C) reduced the inhibition and made the broth more fermentable. The Rhizobium radiobacter (LMG196 and ATCC4720) then produced 69.0 g succinoglycan L-1 under optimized conditions. Once extracted (91.2% purity) and characterized (FT-IR, NMR, GPC and SEM), this led to a new set of results that were better than those found in the literature, since they included the exploitation of the left-over biomass for the production of a valuable exopolysaccharide (41.6 g 100 g-1 RH). The unconstrained multivariate optimization allied to the RH ozonation strategy, followed by pressurized acid hydrolysis, gave rise to promising yields, which confirms the technical viability and the innovative feature of succinoglycan production.

Environmental friendly synthesis of TiO2-ZnO nanocomposite catalyst and silver nanomaterials for the enhanced production of biodiesel from Ulva lactuca seaweed and potential antimicrobial properties against the microbial pathogens

TiO2-ZnO heterogeneous catalytic system provides a good replacement of a homogeneous catalytic reaction due to its easier recovery. In this study, biodiesel was produced from Ulva lactuca seaweeds using TiO2–ZnO nanocomposite catalysts with particle size of ~12 nm. The size controlled TiO2–ZnO nanocomposite was characterized by powder XRD analysis and TEM. The result of that TiO2–ZnO catalyst is a promising catalyst for the production of biodiesel under mild reaction conditions and high yield of hydroxydecanoic acid conversion of 82.8%. The various conditions optimized for the higher conversion to FAME (15.8 ml of FAME) were 4 wt% catalysts at 4 h under 60 °C and further there is no increase of conversion to FAME above 60 °C–80 °C. The total product yield was calculated as 82.8% of conversion to FAME. The evaluated biodiesel was found to be up to the mark of ASTM standards. The silver nanoparticles (AgNPs) were synthesized by using leftover biomass of algae obtaining after lipid extraction of U.lactuca. AgNPs particle size was achieved as ~12 nm and was confirmed by UV–Visible spectroscopy, XRD and TEM analysis. Antibacterial activities of the synthesized AgNPs were analyzed and compared. The antibacterial activity was excellent against bacterial pathogens and treatment against P. vulgaris shows the maximum zone of inhibition (13.8 mm). The present work identified that the unutilized bioresource such as U.lactuca can be effectively utilized for biodiesel production so as to replace fossil fuel usage.

Simultaneous extraction–reaction process for biodiesel production from microalgae

Biodiesel is a promising sustainable alternative to non-renewable petrodiesel. In this work, oils extracted from microalgae are used for biodiesel production. To simplify the process, the extraction of the oils and their reaction are made to take place simultaneously in one step. Immobilized lipase was used as the catalyst, and supercritical CO 2 (SC-CO 2 ) was used as an extraction solvent and reaction medium. The use of SC-CO 2 allows easy separation of the products and leaves the leftover biomass uncontaminated, allowing it to be utilized in food and pharmaceutical applications. The effects of temperature (35–50 °C), reaction time (2-6 h), and methanol:oil (M:O) molar ratio (8:1–16:1) on biodiesel yield were investigated. Within 6 h, the maximum biodiesel production yield was found to be 19.3% at a temperature of 35 °C and at an M:O molar ratio of 8:1. The results hold promise in simplifying the microalgae-to-biodiesel production process. • Supercritical CO 2 (SC-CO 2 ) was used as an extraction solvent and reaction medium. • Immobilized lipase was used as the catalyst. • Effects of temperature, reaction time, and methanol:oil molar ratio were studied. • A biodiesel production yield of 19.3% was obtained.

Biomass feedstock supply chain network design with biomass conversion incentives

Biomass has the potential to create sustainable energy systems, which is critical for societal welfare. A major issue regarding biomass resources is crop residues or leftover biomass that is burnt by farmers after harvesting; this happens due to high transportation costs which make burning the cheapest way to remove the residue. We develop a decision support system using a large-scale linear program with the goal of maximizing profit with and without the emission cost. This system helps identify farms that would benefit society were they to be incentivized under a biomass crop assistance program (BCAP). A case study of leftover corn stover in the state of North Dakota is analyzed to validate the model. Our results reveal that an incentive of $7.20 per ton of corn stover converted to ethanol when 20% of rail capacity is allocated is ideal, as it produces the lowest emissions of 16,784,953 metric tons with a $73,462,599 profit. Furthermore, penalizing emissions resulting from the transportation of corn stover also helps reduce emissions; a suitable value for the penalty could be $71.7 per metric ton of CO2 emitted. Such a policy would result in reducing dependency on petroleum, thus promoting a sustainable biomass supply chain.

Rose biomass as a potential biosorbent to remove chromium, mercury and zinc from contaminated waters

Rose flowers are used for the extraction of essential oil or rose water. The vast majority of the leftover biomass is generally wasted. The aim of the present study was to analyse the rose flower biomass as a potential biosorbent for metals chromium(III), mercury(II) and zinc(II), to remove them from industrial effluents. A number of variables were analysed, including untreated, acid-treated and base-treated biomass, biomass dosage, metal ion concentration, contact time, and pH. Increase in biomass dosage and metal ion concentration increased biosorption. The pH proved to be a very important factor and all the metals showed high adsorption at slightly acidic to moderately basic pH 6–10. They showed very low uptake at low pH. Contact time had little effect on the adsorption capacity of zinc, but was very crucial in the case of mercury. Base treatment favoured adsorption of mercury and zinc. The adsorption of Cr3+, Hg2+ and Zn2+ on rose biomass can be explained by Langmuir and Freundlich isotherms equally well, and the adsorption process followed pseudo second order kinetics. The study suggests that the rose flower biomass can be used in the removal of these metals from contaminated waters employing optimum conditions indicated by the present work.