Study on supercritical fluid extraction of solanesol from industrial tobacco waste

Tobacco as bioenergy and medical plant for biofuels and bioproduction

Tobacco, a widely cultivated crop, has been extensively utilized by humans for an extended period. However, the tobacco industry generates a significant amount of organic waste, and the effective utilization of this tobacco waste has been limited. Currently, most tobacco waste is either recycled as reconstituted tobacco sheets or disposed of in landfills. However, tobacco possesses far more potential value than just these applications. This article provides an overview of the diverse uses of tobacco waste in agriculture, medicine, chemical engineering, and energy sectors. In the realm of agriculture, tobacco waste finds primary application as fertilizers and pesticides. In medical applications, the bioactive compounds present in tobacco are fully harnessed, resulting in the production of phenols, solanesol, polysaccharides, proteins, and even alkaloids. These bioactive compounds exhibit beneficial effects on human health. Additionally, the applications of tobacco waste in chemical engineering and energy sectors are centered around the utilization of lignocellulosic compounds and certain fuels. Chemical platform compounds derived from tobacco waste, as well as selected fuel sources, play a significant role in these areas. The rational utilization of tobacco waste represents a promising prospect, particularly in the present era when sustainable development is widely advocated. Moreover, this approach holds significant importance for enhancing energy utilization.

Extraction and Purification of Nicotine from Tobacco Rhizomes by Supercritical CO2

Currently, in the ongoing development of the tobacco industry, a large amount of tobacco rhizomes is discarded as waste. These wastes are usually disposed of through incineration or burial. However, these tobacco wastes still have some economic value. High-purity nicotine has a promising market outlook as the primary raw material for electronic cigarette liquid. Nicotine is not only found in tobacco leaves but also in the rhizomes of tobacco plants. This study presents a method for treating tobacco waste and extracting high-purity nicotine from it. After mixing the raw material powder and entrainer in specific ratios, as much of the nicotine in tobacco roots can be extracted as possible using supercritical carbon dioxide extraction. The effects of temperature, the ratio of the entrainer, and the volume fraction of ethanol in the entrainer on the nicotine yield in supercritical fluid extraction (SFE) at 25 MPa for 120 min were discussed. By using 90% ethanol (a raw material mass-to-volume ratio of 1:5) as the entrainer, we obtained the highest nicotine yield of 0.49% at 65 °C. Meanwhile, the purity of the crude extract was 61.71%, and after purification, it increased to 97.57%. In this way, we can not only obtain nicotine with market value but also further reduce the harm to the environment caused by tobacco waste disposal.

Nicotiana tabacum Leaf Waste: Morphological Characterization and Chemical-Functional Analysis of Extracts Obtained from Powder Leaves by Using Green Solvents

Tobacco cultivation and industrialization are characterized by the production of trillions of pre-harvest and post-harvest waste biomasses each year with the resulting negative effects on the environment. The leaves of blunt, pre-harvest waste, could be further used to obtain bioactive metabolites, i.e., polyphenols and alkaloids, for its potential cosmetic use. This study was conducted to obtain bio-compounds from pre-harvest tobacco leaf waste (var. Virginia) by applying conventional and green solvents (NaDES). Leaves and ground leaf waste were characterized based on their microscopic features. Conventional solvents, such as water, acetone, ethanol, and non-conventional solvents, such as Natural Deep Eutectic Solvents (NaDES), i.e., sucrose:lactic acid (LAS), frutose:glucose:sucrose (FGS), lactic acid:sucrose:water (SALA), choline chloride:urea (CU), and citric acid: propylene glycol (CAP) were used for bioactive extraction from tobacco waste powder. CU, FGS, and acetone/ethanol had similar behavior for the best extraction of alkaloids (6.37-11.23 mg ACE/g tobacco powder). LAS, FGS, SALA, and CU were more effective in phenolic compound extraction than conventional solvents (18.13-21.98 mg AGE/g tobacco powder). Because of this, LAS and SALA could be used to obtain phenolic-enriched extracts with lower alkaloid content rather than CU and FGS. Extracts of the powder obtained with conventional solvent or CU showed a high level of sugars (47 mg/g tobacco powder) The ABTS antioxidant capacity of tobacco leaf powder was higher in the extracts obtained with CU, FGS, and acetone (SC₅₀ 1.6-5 µg GAE/mL) while H₂O₂ scavenging activity was better in the extracts obtained with LAS, CAP and SALA (SC₅₀ 3.8-8.7 µg GAE/mL). Due to the biocompatibility of the NaDES with the components of tobacco leaf waste, the opportunity to apply these extracts directly in antioxidant formulations, such as cosmetics, phytotherapic, and other formulations of topic use seems promising. Furthermore, NaDES constituents, i.e., urea and organic acid can also have beneficial effects on the skin.

Integrating diverse plant bioactive ingredients with cyclodextrins to fabricate functional films for food application: a critical review

The popularity of plant bioactive ingredients has become increasingly apparent in the food industry. However, these plant bioactive ingredients have many deficiencies, including low water solubility, poor stability, and unacceptable odor. Cyclodextrins (CDs), as cyclic molecules, have been extensively studied as superb vehicles of plant bioactive ingredients. These CD inclusion compounds could be added into various film matrices to fabricate bioactive food packaging materials. Therefore, in the present review, we summarized the extraction methods of plant bioactive ingredients, the addition of these CD inclusion compounds into thin-film materials, and their applications in food packaging. Furthermore, the release model and mechanism of active film materials based on various plant bioactive ingredients with CDs were highlighted. Finally, the current challenges and new opportunities based on these film materials have been discussed.

Current advances of functional phytochemicals in Nicotiana plant and related potential value of tobacco processing waste: A review

Tobacco is grown in large quantities worldwide as a widely distributed commercial crop. From the harvest of the field to the process into the final product, a series of procedures generate enormous amount of waste materials that are rarely recycled. In recent years, numerous potential bioactive compounds have been isolated from tobacco, and the molecular regulatory mechanisms related to the performance of some functionalities have been identified. This review describes the source of tobacco waste and expounds a large amount of biomass during the tobacco processing, and the necessity of exploring the reuse of tobacco waste. In addition, the review summarizes the bioactive compounds from tobacco that have been discovered so far, and links them to various functions from tobacco extracts, including anti-inflammatory, antitumor, antibacterial, and antioxidant, thus proving the potential value from tobacco waste reuse. In this regard, nornicotine in tobacco is the culprit of many health issues, while the polyphenols and polysaccharides often contribute to the health benefits of tobacco extract. In addition, it is hard to ignore that realization of these functions of tobacco extracts require the involvement of intestinal flora metabolism, which should be considered in the development of new product dosage forms.

Optimization of MAE for the Separation of Nicotine and Phenolics from Tobacco Waste by Using the Response Surface Methodology Approach

This study intends to valorize by-products of the industrial processing of tobacco to obtain nicotine and phenolics as value-added compounds. Three influential parameters of the microwave-assisted extraction-MAE (temperature, treatment time, and solvent/solid ratio) were studied for the optimization of the extraction protocol for tobacco leaves and three types of waste-scrap, dust, and midrib, respectively. Nicotine was the dominant bioactive compound in all extracts, ranging from 1.512 to 5.480% in leaves, 1.886 to 3.709% in scrap, 2.628 to 4.840% dust, and 0.867 to 1.783% in midrib extracts. Five phenolic compounds were identified and quantified, predominated by chlorogenic acid and rutin. Additionally, total phenol content and antioxidant activity were determined using spectrophotometric assays. Optimization was performed in two aspects: to obtain a maximum extraction yield with minimum nicotine content and to obtain a maximum extraction yield with maximum nicotine content. These findings demonstrate that tobacco waste is a valuable source of bioactive compounds and MAE can be a promising alternative technique to obtain extracts rich in targeted bioactive compounds, especially nicotine.

A Simple and Standardized Method for the Determination of Total Solanesol in Potato Leaves and Its Extracts Based on HPLC-MS

BACKGROUND

Solanesol is an important pharmaceutical intermediate raw material, mainly used to synthesize coenzyme Q10, vitamin K2. It can be found prominent in potato stems and leaves. But now potato stems and leaves are always abandoned or discarded as they are not suitable for use as feed in aquaculture or other purposes. These agricultural waste resources can be reutilized as the corresponding extracts.

OBJECTIVE

To develop a simple and standardized method for the detection of total solanesol in potato leaves and its extracts.

METHODS

N-hexane was chosen as the extraction solvent for three times in the solanesol extraction from potato leaves. HPLC-MS was used for the detection.

RESULTS

The LOQ was 0.3 µg/g and the linear range was from 0.1  to 50 µg/mL. The precision and stability were evaluated by the relative standard deviations (RSDs) of three samples (potato leaves, Extract-1, Extract-2) for interday and intraday. The accuracy of the method was evaluated by the recoveries of three different spiked concentrations of solanesol for three samples, and results showed it ranged from 80.7% to 99.0% with RSDs less than 8.7%.

CONCLUSIONS

The method we established can provide a simple and standardized way for the extraction and detection of total solanesol.

HIGHLIGHTS

The work laid a foundation for the resource reutilization of potato stem and leaf.

High Voltage Electric Discharge for Recovery of Chlorogenic Acid from Tobacco Waste

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

Secondary Bioactive Metabolites from Plant-Derived Food Byproducts through Ecopharmacognostic Approaches: A Bound Phenolic Case Study

The climate emergency and the risks to biodiversity that the planet is facing nowadays, have made the management of food resources increasingly complex but potentially interesting. According to FAO, one-third of the edible parts of food produced throughout the whole food supply chain gets lost or wasted globally every year. At the same time, demographic growth makes it necessary to change course toward sustainable economic development in order to satisfy market demands. The European Union supported the idea of a Circular Economy from 2015 and arranged annual Action Plans toward a greener, climate-neutral economy. Following the biorefinery concept, food waste becomes byproducts that can be recovered and exploited as high added-value materials for industrial applications. The use of sustainable extraction processes to manage food byproducts is a task that research has to support through the development of low environmental impact strategies. This review, therefore, aims to take stock of the possibilities of extracting molecules from food waste biomass following ecopharmacognostic approaches inspired by green chemistry guidelines. In particular, the use of innovative hybrid techniques to maximize yields and minimize the environmental impact of processes is reviewed, with a focus on bound phenolic extractions.

Solid-state Co-cultivation of Bacillus subtilis, Bacillus mucilaginosus, and Paecilomyces lilacinus Using Tobacco Waste Residue

Agro-industrial wastes are excellent sources for solid-state culture to produce spores of microorganisms, whereas microbial co-cultivation is not fully exploited in solid-state culture. In this work, the co-cultivation of different strains of Bacillus subtilis, and three microbes of B. subtilis, Bacillus mucilaginosus, and Paecilomyces lilacinus was studied using a solid medium only composed of water and tobacco waste residue after extraction of nicotine and solanesol. The influences of matrix thickness, moister, temperature, and ratio of three microbes in seed on the cell growth and spore formation were studied. The maximum viable cells and spores of each microbe reached 1013 cfu/g when cultured alone at 30 °C in a medium containing 58.3% moisture. Co-cultivation of microbes stimulated cell growth and maximum viable cells of each microbe reached 1014 cfu/g, while spore production was inhibited and decreased to 1011 cfu/g. With decreasing amount of P. lilacinus in seed, total amount of spores was increased. When the seed with a ratio of 6:3:1 for B. mucilaginosus, B. subtilis, and P. lilacinus was inoculated, the total amount of spores reached 4.14 × 1012 cfu/g and the ratio was 1.7:0.7:1. These results indicate the potential of solid-state cultivation in the high production of spores from tobacco waste residue at low cost.

Bioactivities and Medicinal Value of Solanesol and Its Accumulation, Extraction Technology, and Determination Methods

Solanesol, an aliphatic terpene alcohol composed of nine isoprene units, is mainly found in solanaceous plants. Particularly, tobacco (Nicotiana tabacum), belonging to the Solanaceae family, is the richest plant source of solanesol, and its leaves have been regarded as the ideal material for solanesol extraction. Since the discovery of solanesol in tobacco, significant progress has been achieved in research on solanesol’s bioactivities, medicinal value, accumulation, extraction technology, and determination methods. Solanesol possesses strong free radical absorption ability and antioxidant activity owing to the presence of several non-conjugated double bonds. Notably, solanesol’s anti-inflammatory, neuroprotective, and antimicrobial activities have been previously demonstrated. Solanesol is a key intermediate in the synthesis of coenzyme Q10, vitamin K2, and the anticancer agent synergiser N-solanesyl-N,N′-bis(3,4-dimethoxybenzyl) ethylenediamine. Other applications of solanesol include solanesol derivative micelles for hydrophobic drug delivery, solanesol-derived scaffolds for bioactive peptide multimerization, and solanesol-anchored DNA for mediating vesicle fusion. Solanesol accumulation in plants is influenced by genetic and environmental factors, including biotic stresses caused by pathogen infections, temperature, illumination, and agronomic measures. Seven extraction technologies and seven determination methods of solanesol are also systematically summarized in the present review. This review can serve as a reference for solanesol’s comprehensive application.

A benign process for the recovery of solanesol from tomato leaf waste

Solanesol, the precursor for the synthesis of coenzyme Q10, is currently recovered from tobacco leaves by conventional extraction techniques that require multiple purification steps and a large amount of organic solvents. We recently identified tomato leaves as an alternative source of solanesol and hypothesized that a high-pressure CO2 extraction could be used as a clean extraction process. The effect of CO2 pressure and temperature on the extraction of solanesol was determined to achieve high yield and purity. It was found that solanesol could be extracted efficiently by subcritical CO2 at 25 °C from tomato leaves. The extract contained 40% solanesol and other active compounds such as vitamin K1. A higher level of purity of 93% was achieved using a secondary purification step. Different conventional methods for solanesol extraction was compared to determine the most efficient technique for production of solanesol from tomato leaf. The highest yield of solanesol was achieved at nearly 1% dry weight with using subcritical CO2, which was superior to conventional methods.