With the implementation of modern innovative technologies in agriculture, productivity is raised with profuse waste generation globally. Most often, huge agricultural wastes are burnt (stubble burning) and release harmful emissions into the air. It causes concern to the public and animal health, productivity (land and water), and economic loss. Bio-alcohols from the fermentation of agricultural waste do not compete with food, support other energy resources, and contribute to a circular economy and employment generation, together with clean energy. At present, most countries allow blending of bio-alcohols with gasoline for low emissions, energy security, saving foreign exchange, and socioeconomic upliftment with employment generation. Commercially, bio-alcohol production for biofuel is dependent on substrates like cellulose content/fermentable carbohydrates, microorganisms for fermentation, pre-treatment processes, inhibitory/toxic compounds (furfural, ferulic, phenolic compounds), growth medium, fermentation mode (fed-batch/continuous), engine performance (spark ignition/compression ignition), etc. Therefore, it is worthwhile to study the different aspects of bio-alcohol generation from agricultural wastes for sustainable, economically viable, clean bioenergy production.

Guggulsterone is a phytosteroid derived from the oleo-gum resin of the critically endangered plant Commiphora wightii. This molecule has attracted increasing attention due to its excellent biochemistry potential and the compound has consequently been evaluated in clinical trials. With a low concentration in natural resources but wide medicinal and therapeutic value, chemists have developed several synthetic routes for guggulsterone starting from various steroid precursors. Moreover, numerous studies have attempted to modify its structure to improve the biological properties. Nowadays, green and sustainable chemistry has also attracted more attention for advanced chemical processes and reactions in steroid chemistry. The present review aimed to summarize the literature and provide an update about the improvements in the chemical synthesis and structural modification of guggulsterone from the view of green chemistry. Moreover, this review encompasses the improved activities of structurally modified guggulsterone derivatives. We expect that the information provided here will be useful to researchers working in this field and on this molecule.

Microalgae comprise miscellaneous groups, mainly oxygenic photosynthetic organisms reported to have diverse biotechnological and industrial applications. The applications of microalgal biomass include the production of food, feed, fuels, bioactive compounds, fertilizers, antioxidants, pigments, etc. The renewable and carbon-neutral nature of microalgal biofuels has placed them at the frontline of bioenergy research. These biomass-based industries can achieve their targets by developing sustainable and economically feasible cultivation systems. Among the available systems, raceway ponds have been found to be the most promising and effective for large-scale microalgal biomass production. Accomplishing good biomass productivity for a sustainable period in an open raceway pond is quite challenging as it depends on various parameters. Starting from the design, several environmental and biological factors determine biomass productivity in open pond systems. The understanding of these critical parameters and their proper monitoring is essential for developing a successful commercial-scale algal biomass production.

Bakuchiol is an emblematic meroterpene class of natural product extracted from Psoralea corylifolia. It has been reported to possess a broad range of biological and pharmacological properties and is considered as a leading biomolecule. It is highly desirable to devise an efficient approach to access bakuchiol and its chemical biology applications. In this review we provided structural features, isolation methods, various chemical routes and late-stage functionalization (LSF) approaches for bakuchiol and its derivatives. Moreover, this review encompasses the structure-activity relationships (SAR), value-added contributions and future perspectives of bakuchiol

[This corrects the article DOI: 10.1039/D1RA08771A.].

The pulsed magnetic field (PMF) was adopted for the enhancement of lipid in Chlorella vulgaris. The average biomass and lipid content in outdoor conditions were found to be 0.315 g.L-1 and 20-25% respectively. The effect of magnetic flux density in the range of 600-900 mG on biomass production and lipid content was studied. A magnetic flux density of 700 mG at 1Hz for 4 h per day was found to be optimum, which yielded a maximum dry cell weight of 0.61 g.L-1, two-fold than the normal condition, with a lipid content of 55.2%. FTIR analysis evidenced that the PMF treatment increased the active oxygen, which could be attributed to the enhancement of growth and lipid of C. vulgaris.

The present study demonstrated the growth of microalgae in wastewaters to underline a process coupled with biofuel production. Green alga, Scenedesmus sp., was cultivated in various domestic wastewaters (S1, S2, S3). Biomass 0.84, 0.68, 0.73 (g/L) and lipid productivity 8.6, 5.6, 6.2 (mg/L/d) were obtained from wastewaters S1, S2, S3 respectively in 20 days. Removal of 66% inorganic phosphorous, 99% nitrite, 86% nitrate, 80% ammoniacal nitrogen, 84% calcium and 76% sulphate from the initial high level of wastewater nutrients were achieved by algal cultivation. The total fatty acid (FA) produced by the alga in these conditions consisted of 43.3% saturated FA, 44.4% monounsaturated FA, and 12.3% polyunsaturated FA. The pilot scale study could be implemented for the simultaneous nutrient removal and algal oil production by utilizing domestic wastewaters.

Microalgal biomass is a renewable, carbon-neutral resource and an excellent alternative to petroleum footed fuels. In this work the open outdoor raceway pond system was used for the cultivation of Chlorella vulgaris. The biomass productivity was 31.5 mg L-1 d(-1) and lipid content 25 +/- 5% when cultivated in low cost medium (Urea, Superphosphate and Potash at 91.9, 72.9 and 62.7 mg L-1 where the pH was 8.03) formulated by RSM. The highest FAME yield was 67% under the optimized conditions of H2SO4 at 4%; reaction time at 4 h; methanol-hexane as co-solvent in the ratio of 2:1; and temperature at 80 degrees C for 100 mg of algal lipid. The DU, LCSF, CFPP, CN, PP, CP of the biodiesel evidenced high quality, which corroborate with International standards. The diesel engine performance showed a blend of B50 which is superior in quality compared to B20 and B40 blends and the commercial diesel. Furthermore, reduction of brake-specific fuel consumption at 100% load showed 273.9 gficW h in B50 whereas for commercial diesel it was 275 gikW h. There was 40-55% reduction of CO, HC, and emissions compared to commercial diesel. Thus, this research emphasizes that microalga-based biodiesel is cost-effective and eco-friendly choice for biodiesel. (C) 2018 Elsevier Ltd. All rights reserved.

Fatty acid methyl esters (FAME) derived from lipids of microalgae is known to have wide bio-functional materials including antimicrobials. FAME is an ideal super-curator and superior anti-pathogenic. The present study evaluated the efficiency of FAME extracted from microalgae Scenedesmus intermedius as an antimicrobial agent against Gram positive (Staphylococcus aureus, Streptococcus mutans, and Bacillus cereus) Gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and Fungi (Aspergillus parasiticus and Candida albicans). The minimal inhibitory concentration (MIC) for the gram negative bacteria was determined as 12-24 mu g mL(-1), whereas MIC for gram positive bacteria was 24-48 mu g mL-1. MIC for the fungi was as high as 60-192 mu g mL(-1). The FAME profiles determined by gas chromatography showed 18 methyl esters. Among them, pharmacologically active FAME such as palmitic acid methyl ester (C16:0) was detected at high percentage (23.08%), which accounted for the bioactivity. FAME obtained in this study exhibited a strong antimicrobial activity at the lowest MIC than those of recent reports. This result clearly indicated that FAME of S. intermedius has a strong antimicrobial and antioxidant property and that could be used as an effective resource against microbial diseases.

Production, extraction and purification of C-Phycoerythrin pigment from a marine cyanobacterium, Phormidium persicinum NTDP01 was carried out in this study. Strain was grown in MN+ medium and molecularly characterized using 16S rRNA gene sequence. Pigments were extracted by means of freeze and thaw method and were characterized by spectral absorbance by UVVis spectrophotometer, spectrofluorometer and FTIR. The purity (A565/A280) of crude pigment was found to be 1.5. The crude pigment was concentrated by using a two step Ammonium sulphate precipitation, initially by 25% followed by 60%. It has been increased the purity ratio to 2.9. It was further purified by size exclusion chromatography using Sephadex G-150 column. Finally by purification through column chromatography an yield of 17.5 mg.g -1 C-Phycoerythrin with 5.9 purity ratio (A568/A280). The 16S rDNA sequences were deposited to GenBank with an accession number of KC859032.

Microalgae are expected to play promising role in the production of biofuel in current research. Two of marine diatoms, Navicula sp. and Amphora sp. were isolated and their growth rate was also studied. Total lipid content was analyzed in stationary growth state under normal conditions. By the two stage process, both the diatoms were subjected to nitrogen and silicon undersupplied for five days and the total lipid accumulation in the diatoms were found to be increased during nutrient deficiency period. The nutrient deficit conditions prone to increased total lipid content and also altered the fatty acid profile in diatom. The total lipid content of Navicula sp. and Amphora sp. were found to be 34.93% DCW and 41.10% DCW under normal conditions and in nitrogen deficiency conditions it has been increased to 60.71% DCW and 64.72% DCW respectively. The major fatty acids were found to be cis-10-Heptadecanoic acid (27.54%) and stearic acid (24.57%). The level of saturated and monounsaturated fatty acids were found to be high in both the diatoms. The presence of low level of polyunsaturated fatty acids indicated that these two organisms could find future application in bioenergy production.

Morphology and cytological studies are the basis for the conventional identification and taxonomy of cyanobacteria.But it is found that most of the cyanobacterial species change their morphological features in accordance with critical conditions of the ecosystem.Therefore, conventional methods may not be sufficient for the identification of the organism at the species level.In this study, molecular characterization is recommended as a much more reliable technique for better identification of cyanobacteria.Marine and fresh water samples were collected from Kurumadai and Tiruchirappalli respectively.From the purified samples, three strains, Leptolynbya valderiana NTDM10, Oscillatoria boryana NTDM11and Planktothrix pseudoagardhii NTRD01 were selected for the further molecular characterization based on the 16S rDNA sequences.The sequences were deposited to GenBank with accession numbers JQ867392, JQ867393 and JQ867394.Evolutionary relationships and secondary structure prediction was carried out with the sequences.Biomolecular characteristics of the three cyanobacterial strains were also studied by FTIR spectroscopy.

The structural features of microalgal cell make it too difficult to extract the total lipid content of the cell as such.Thus, the cell disruption before lipid extraction becomes mandatory and has to be cost-effective.In the present study various methods and combination of few methods were adopted for effective extraction in order to choose the most effective cell disruption method for the complete extraction of lipids from a selected indigenous freshwater isolate, Scenedesmus sp.NTEB03.Interestingly, we found that grinding and bead-beating method showed two fold increased lipid productivity (23.2%) than the other methods tested.Biomass and lipid productivity of Scenedesmus sp., was found to be 0.0418 g L -1 d -1 and 4.3 mg L -1 d -1 respectively.Fatty acid profiles revealed that oleic (C18:1) and linoleic acid (C18:2) content being higher in the lipids, which are most appropriate for the biodiesel production.A novel strategy for most effective, simple method for cell disruption in Scenedesmus sp., was grinding/bead-beating, which is the most suitable method for complete extraction of biofuel grade lipids.

To evaluate fatty acid composition and the antimicrobial activity of the major fraction of fatty acid methyl ester (FAME) extracts from three microalgae collected from freshwater lakes in Theni District, Tamil Nadu, India. Antimicrobial study was carried out by well diffusion method against bacterial as well as fungal pathogens such as Escherichia coli, Staphylococcus aureus, Enterobacter sp., Klebsiella sp., Salmonella typhi, Fusarium sp., Cryptococcus sp., Candida sp., and Aspergillus niger and Aspergillus flavus. The FAME profiles were determined through gas chromatography with a flame ionization detector. The FAME was found to be radial effective in inhibiting the radial growth of both bacterial and fungal pathogens. The FAME extracts exhibited the antibacterial activity against three clinical pathogens, namely, Escherichia coli, Salmonella typhi and Enterobacter sp. with the maximum zone of inhibition of 12.0 mm, 12.0 mm and 11.0 mm, respectively. The FAME showed moderate antifungal activity against Cryptococcus sp. (11.8 mm), Aspergillus niger (10.5 mm), Candida sp. (11.8 mm) and Fusarium sp. (10.4 mm). Gas chromatography-flame ionization detector analysis revealed about 30 different FAMEs. We assume that the observed antimicrobial potency may be due to the abundance of erucic acid methyl ester (C22:0), arachidic acid methyl ester (C20:0), palmitic acid methyl ester (C16:0), cis-11-eicosenoicmethyl ester (C20:1), cis-11, 14-eicosadienoic acid methyl ester (C20:2) and linolenic acid methyl ester (C18:3) in FAMEs which appears to be promising to treat microbial diseases.

In the present study a potential freshwater microalgae Coelastrella sp. was selected for degradation of synthetic dye, Rhodamine B in batch culture system. Effect of several physico-chemical parameters that influence the decolorization followed by degradation ability was investigated (inoculum concentration, initial dye concentration, temperature and pH) and optimal experimental condition was ascertained. The optimum operating conditions were found to be [Dye]=100mgl−1; [temperature]=30°C; with 10% of inoculum at a pH of 8. Under these conditions, a maximum of 80% decolorization of the dye was achieved in 20 days. Peroxidase activity of the isolate was also determined and it was found to be 2.1μmolminmg−1 of protein. The actual break down of the dye was confirmed by using various analytical techniques such as GC–MS, TLC, FTIR and UV–vis spectral analysis. Small aliphatic chains, small chain alcohols and ketones were obtained after degradation of Rhodamine B. These are the evidences that showed that microalgae play a vital role on dye degradation to non-toxic products effectively.

Today, a material science focuses on the nanoparticles synthesis in general and synthesizing them by biological entity in particular for their marvel production and its remarkable property. In this present study, synthesis of gold nanoparticles using photosynthetic microorganisms such as Coelastrella sp. (eukaryotes) and Phormidium sp. (prokaryotes) were reacted with Chloroauric acid (HAuCl4) and bioaccumulation was assessed. Various techniques were adopted for characterization of nanoparticles and compared. It was found to be 25nm sized nanotriangles and 30nm sized spherical shaped nanoparticles were synthesized by prokaryotic and eukaryotic microorganisms respectively by TEM analysis. Biogenic gold nanoparticles have potent antioxidant property and the interaction of gold nanoparticles with DNA was evaluated that biogenic nanoparticles were actively bound to DNA in increased concentration. It was revealed that biogenic nanoparticles have wide range of applications depends on the biological entity used. Selection of suitable biological entity is very much important for the production of nanoparticles with desirable shapes and size for the biomedical applications.

In recent decades, microalgae have acquired attention from pharmaceuticals to biofuels. The growth and total chorophyll content of three economically important microalgae (Chlorella sp. NTAI01, Monoraphidium sp. NTAI02 and Scenedesmus sp. NTAI03) isolated from fresh water body in five selected culture media on different days of incubation was studied for biomass production. Biomass feedstock has reviewed great interest to be used as an alternative and renewable source of energy. All the three organisms showed varied growth pattern and total chlorophyll content in different culture media. However the growth and total chlorophyll content of Chlorella sp. NTAI01 and Monoraphidium sp. NTAI02 was optimum in Half strength Chu 10 medium. In case of Scenedesmus sp. NTAI03 the growth and total chlorophyll content was found to be significant in Bolds Basal medium. The Acidified Bolds Basal medium and BG-11 medium fairly supports the growth of all the three microalgae whereas the Modified Hoaglands medium does not support the microalgal growth. The optimized growth medium will be used for biomass production for biofuel application.