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The present study was designed to study the in vitro antioxidant activity and antibacterial activities of Atylosia rugosa. The antioxidant activities of the extracts were examined using different biochemical assays namely diphenlpicrylhydrazyl (DPPH), hydrogen peroxide radical scavenging activity and the antibacterial activity of the extracts was also evaluated and MIC values were calculated by broth dilution method. The assays, revealed that the ethyl acetate extract exhibited stronger antioxidant activity than that of ethanolic extract, the extracts also prevented the growth of both Gram positive and Gram negative bacteria, the MIC values of ethanolic extract has higher antibacterial than those of the ethyl acetate. The antioxidant and antibacterial activity of the extracts was found to be positively associated with the total phenolic and favonoid content of the extracts. A positive, significant linear relationship between antioxidant activity and TPC and TFC content showed that phenolic compounds and flavonoids were the dominant and possessing antioxidant and antibacterial properties of Atylosia rugosa.

Terpene esters of short-chain fatty acids are essential oils that have big importance in food, cosmetic and pharmaceutical industries as flavours and fragrances. Geraniol and citronellol are the most important substances. Considering the ever-increasing demand for such products, their enzymatic production from natural raw materials by using environmentally friendly and economically attractive processes may prove advantageous. In this contribution, we would like to present an alternative option for the production of geranyl propionate using nanobioconjugates consisting of Candida rugosa lipase adsorbed onto multi-walled carbon nanotubes (CRL-MWCNTs). We investigated the effects of incubation time, temperature, solvent log P and substrate molar ratio, and determined the optimum conditions. The yield of geranyl propionate catalysed by CRL-MWCNTs nanobioconjugates was significantly influenced by two factors, namely, temperature and time of the reaction. Under the optimum reaction conditions of 55 °C, solvent n-heptane (log P = 4.0), geraniol to propionic acid molar ratio of 5:1 and reaction time of 6 h, the use of CRL-MWCNTs resulted in 51.3% production of geranyl propionate. Therefore, the investigation revealed that geranyl propionate was successfully synthesized under mild conditions with reasonably high yield within a short period of time. The CRL-MWCNTs nanobioconjugates demonstrated a potential as economical and environmentally smarter biocatalysts for the production of geranyl propionate.

By the facile adhesion way, the novel composite complex by polydopamine (PDA) and magnetic graphite nanosheets (Fe sub(3)O sub(4)GNSs) has been successfully synthesized. The resulting composite was characterized by means of scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, and Raman spectra, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. Meanwhile, the PDA functionalized Fe sub(3)O sub(4)GNSs (Fe sub(3)O sub(4)GNSs-PDA) was applied for Candida rugosa lipase (CRL) immobilization covalently without any toxic coupling agent. Combining the superior physical properties and chemical stability of Fe sub(3)O sub(4)GNSs and the well biocompatibility, functional characteristics of PDA, the Fe sub(3)O sub(4)GNSs-PDA composite displayed several advantages, including the high enzyme capacity, enzyme activity and stability and a decrease in enzyme loss. Our work demonstrated that the mussel-inspired Fe sub(3)O sub(4)GNSs can be extended to many other applications such as biocatalytic, genetic and industrial.

The potential use of alternative culture media towards the development of a sustainable bioprocess to produce lipases by Diutina rugosa is clearly demonstrated. First, a synthetic medium containing glucose, peptone, yeast extract, oleic acid, and ammonium sulfate was proposed, with lipase activity of 143 U/L. Then, alternative culture media formulated with agro-industrial residues, such as molasses, corn steep liquor (CSL), and olive mill waste (OMW), were investigated. An experimental design was conducted, and only CSL concentration was found to have a positive effect in lipase production. The highest lipase activity (561 U/L) was produced on a mixture of molasses (5 g/L), CSL (6 g/L), OMW (0.5% v/v), 0.5 g/L of ammonium sulfate, and 3 g/L of peptone at 24 h of cultivation. Lipase production was also carried out in a 1-L bioreactor leading to a slightly higher lipase activity at 24 h of cultivation. The semi-purified enzyme exhibits an optimum temperature and pH of 40 °C and 7.0, respectively. Finally, the media cost per unit of lipase produced (UPC) was influenced by the medium components, specially by the inducer used. The lowest UPC was obtained when the agro-industrial residues were combined and used at the improved concentrations.

A water-in-ionic liquid microemulsion ([Bmim]PF sub(6)/Tween20/H sub(2) O) was applied as reusable reaction medium to esterify phytosterols with fatty acid by Candida rugosa lipase (CRL) successfully. Two kinds of commercial CRLs, AY30 and AYS which cannot effectively catalyze esterification in conventional reaction system were found effective in the microemulsion system. Effects of reaction parameters on esterification were investigated; results showed that the conversion rate of 87.9 and 95.1 % was obtained in 24 and 48 h of reaction, respectively, under the optimized condition: the molar ratio of water to Tween 20 (w sub(0) value) at 5.4, Tween 20 at a concentration of 305 mM, 50 degree C,pH 7.4, 10 % of enzyme loading (w/w, with respect to total reactants), and phytosterols/lauric acid molar ratio of 1:2. Moreover, by using n-hexane as the extraction agent, the lipase-encapsulated microemulsion could be reused at least seven times (>168 h) without significant changes in the conversion rate, while achieving a purpose of simple separation and purification.

This study aimed to (i) prepare functionalized maghemite nanoparticles for immobilization of Candida rugosa lipase (CRL) by covalent binding, (ii) evaluate the application of the immobilized derivative in the hydrolysis of waste cooking oil (WCO) to fatty acids, and (iii) assess the potential of the hydrolyzed material for biodiesel production by hydroesterification. Maghemite (γFe2O3) obtained by precipitation of Fe3Cl2 with NH4OH served as an efficient support for covalent immobilization of CRL. Fourier-transform infrared spectroscopy and hydrolytic activity analysis indicated that CRL was covalently immobilized on the surface of the maghemite support. The derivative showed an activity of 166.62 ± 8 U g−1 in WCO hydrolysis at 40 °C and pH 6. Scanning electron microscopy revealed that, after lipase immobilization, nanoparticles became more dispersed, which is advantageous for biocatalysis reactions, as it increases the contact area with the substrate. WCO hydrolysis afforded 96 ± 0.2 wt% free fatty acids. In the second step, free fatty acids were subjected to chemical esterification with sulfuric acid, affording 94.4 ± 0.02 wt% fatty acid methyl esters (biodiesel). The findings of this study contribute to the field of biotechnology and may promote the development of enzymatic technologies for the synthesis of products of economic and social interest.

Agastache rugosa (Fisch. & C. A. Mey.) Kuntze has been widely studied because of its high medicinal and edible value. Establishing the priority protected area of wild A. rugosa can provide scientific basis for the protection of germplasm resources. In this study, we predicted the potential suitability distribution area of A. rugosa under the current and future climate scenarios with the MaxEnt model, and the dominant climate factors affecting the distribution of A. rugosa were analyzed. Based on the above results, we predicted the priority protected areas of A. rugosa with the Marxan model. The results showed that A. rugosa is mainly distributed in the eastern and central regions of China at present. In future, the suitable area of A. rugosa will increase, otherwise a few areas will shrink back and migrate to the high latitude areas as a whole. Hydrothermal conditions are the main environmental factors affecting the distribution of A. rugosa . The priority protected areas of A. rugosa are mainly distributed in Chongqing, eastern Sichuan, southern Guizhou, western Hunan and Hubei and southwestern Shaanxi, which are basically consistent with the highly suitable areas predicted by Maxent model. The results of this study are of great significance for the protection and rational utilization of species of Agastache.

A greener processing route to replace the current environmentally-unfriendly esterification technique to produce biofuels such as pentyl valerate (PeVa) was explored. This study statistically optimized the covalent immobilization of Candida rugosa lipase (CRL) onto biomass-based nanocellulose-silica (NC-SiO2) reinforced polyethersulfone (PES) membrane to synthesize PeVa. Raman spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and atomic force microscopy of NC-SiO2-PES/CRL proved that CRL was successfully conjugated to the membrane. The optimized Taguchi Design-assisted immobilization of CRL onto NC-SiO2-PES membrane (5% glutaraldehyde, 4 h of immobilization, 20 mg/mL CRL concentration, 40 °C and pH 5) gave 90% yield of PeVa in 3 h. The thermal stability of NC-SiO2-PES/CRL was ~ 30% greater over the free CRL, with reusability for up to 14 successive esterification cycles. In a nutshell, the greener NC-SiO2-PES membrane effectively hyperactivated and stabilized the CRL for the esterification production of PeVa. This research provides a promising approach for expanding the use of sustainably sourced NC and SiO2 nanoparticles, as fillers in a PES for improving CRL activity and durability for an extended catalytic process.

For the first time is reported the comparison of solid biocatalysts derived from Candida rugosa lipase (CRL) immobilized on different lignocellulosic wastes (rice husk, brewer’s spent grain, hemp tea waste, green tea waste, vine bark, and spent coffee grounds) focusing on the characterization of these materials and their impact on the lipase-support interaction. The wastes were subjected to meticulous characterization by ATR-FTIR, BET, and SEM analysis, besides lignin content and hydrophobicity determination. Investigating parameters influencing immobilization performance revealed the importance of morphology, textural properties, and hydrophobic interactions revealed the importance of morphology, textural properties and especially hydrophobic interactions which resulted in positive correlations between surface hydrophobicity and lipase immobilization efficiency. Hemp tea waste and spent coffee grounds demonstrated superior immobilization performances (7.20 U/g and 8.74 U/g immobilized activity, 102.3% and 33.5% efficiency, 13.4% and 15.4% recovery, respectively). Moreover, they demonstrated good temporal stability (100% and 92% residual activity after 120 days, respectively) and retained 100% of their immobilized activity after five reuses in the hydrolysis of p-nitrophenyl palmitate in hexane. In addition, the study of enzymatic desorption caused by ionic strength and detergent treatments indicated mixed hydrophobic and electrostatic interactions in rice husk, vine bark, and spent coffee grounds supports, while hemp tea waste and green tea waste were dominated by hydrophobic interactions. Graphical abstract