In situ process Transesterification FAMEs Chlorella pyrenoidosa a b s t r a c tIn this study different methods were applied for lipids extraction from the dry biomass of Chlorella pyrenoidosa. The survey was carried under different conditions seeking comparative assessment of extraction methods. The method using chloroform:methanol (2:1 v/v) showed the highest lipid extraction followed by methanol, chloroform, ethanol, and hexane.Afterward, we also assessed the relative influence of the solvent extractor selectivity on the overall FAMEs (Fatty Acids Methyl Esters) yield. The application of the transesterification process on the several lipidic extracts was compared with direct transesterification process from dry biomass. In the extraction using chloroform:methanol system a larger amount of lipids was obtained but the conversion to FAMEs using transesterification process was the lowest from lipids. However, despite the amount of extracted lipids with methanol being smaller, its conversion to FAMEs was higher from lipids. In addition, the extraction with methanol followed by transesterification process also resulted in a higher FAMEs yield from biomass than direct transesterification process using methanol.ª (M.G.M. D'Oca).A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m h t t p : / / w w w . e l s e v i e r . c o m / l o c a t e / b i o m b i o e b i o m a s s a n d b i o e n e r g y 3 5 ( 2 0 1 1 ) 1 5 3 3 e1 5 3 8 0961-9534/$ e see front matter ª

This study aimed to evaluate the contribution of three diatom species on the lipid content of bioflocs, their permanence on the bioflocs and influence on the growth performance of juvenile shrimps. Juveniles of Litopenaeus vannamei were reared (30 days; three replicates per treatment) in biofloc systems inoculated with diatoms Amphora coffeaeformis (A), Cylindrotheca closterium (C), Conticribra weissflogii (W), or biofloc only (BF, chlorophycean rich). Water quality parameters were monitored daily and the microbiota on days 1, 10, 20 and 30. The lipid content and fatty acid profiles of bioflocs were analyzed at the end of the experiment. Shrimp survival rate (99%) at treatment A was significantly higher than at BF. The bioflocs in A treatment presented the highest lipid content, differing significantly from BF and W. The content of EPA (20:5) (n-3) was significantly higher in A and lower in BF, while linoleic acid (18:2) (n-6) was significantly higher in BF. The results indicate that high cell density of diatoms can be successfully maintained with silicate addition in biofloc systems and that the pennate A. coffeaeformis and the centric C. weissflogii are potentially better suited than the pennate C. closterium as food supplements for shrimp diets in biofloc nurseries system.

Sarcocornia ambigua is a perennial glasswort, native of South America and a potential new seed-oil crop and forage for direct irrigation with salt water. Small seeds develop inside fertile segments of its cylindrical leafless shoots and, at the harvest, seeds are typically mixed with remnant cellulose material difficult to separate. This work evaluated different extraction methods and the composition of total esterified fatty acids in a meal of ground fertile shoots of S. ambigua, seeking for an alternative primary matter and larger yield of total lipids. The highest lipid yield was obtained with a chloroform:methanol mixture (2:1)(v/v) (5.2% of dry weight). The most abundant polyunsaturated fatty acids in the meal were linoleic acid (C18:2; 21.4%) and oleic acid (C18:1; 18.3%). Fifty six percent of the lipids in S. ambigua meal were saturated and palmitic acid (C16:0) was the main fraction (19.8%). Long-chain fatty acids (≥ C20) represented 29.5% of the lipids. Most abundant long-chain fatty acids were behenic acid (C22:0; 7.1%), lignoceric acid (C24:0; 5.3%) and montanic acid (C28:0; 4.0%). The percentage of saturated lipids in S. ambigua meal was higher than that of vegetable oils with a MUFA nutritional profile and some of these lipids have known bioactive properties.

Sarcocornia ambigua (Michx.) M.A. Alonso & M.B. Crespo is the most widely distributed species of the perennial genus of glasswort in South America, and it shows great biotechnological potential as a salt-water irrigated crop. Qualitative and quantitative compositions of fatty acids were determined in the seeds of S. ambigua that were cultivated in southern Brazil. Hexane extraction of the seed oil from S. ambigua yielded 13% of total lipids. The GC-FID (Gas Chromatography Flame Ionization Detector) analysis of the hexane extracts showed five prominent peaks for the seed oil: 42.9 wt.% linoleic-ω6 acid (18:2), 20.4 wt.% palmitic acid (16:0), 18.5 wt.% oleic acid (18:1), 4.5 wt.% stearic acid (18:0) and 4.0 wt.% linolenic-ω3 acid (18:3). The sum of the saturated palmitic and stearic acids (24.8%) in S. ambigua seed oil exceeded values cited for commercial oils use, as well as the seed oil from the cultivated annual glasswort Salicornia bigelovii. No undesirable fatty acid components were found in S. ambigua seed oil, and it could be recommended for animal consumption or biofuel production.

This work reports, for the first time, the synthesis of new fatty N-acylamino hydrazides and demonstrates the activity of these compounds as low-molecular-weight organic gelators and templates for preparation of gold nanoparticles (AuNPs).

In this work, an efficient and reusable pyrrolidinium ionic liquid (PyrrIL) catalysis system was developed and used in a Knoevenagel condensation reaction of long-chain aldehydes with several 1,3-dicarbonyl compounds.

This article proposes an easy, quick, and efficient microwave method for the routine laboratory extraction of lipids from wet microalgae paste. A microwave synthesis instrument is used, and time and temperature are optimized using a central composite design. A chloroform/methanol mixture (2:1 v/v) is used as extractor solvent and the ideal condition is 1 min of microwave irradiation at 80 °C using power mode at 300 W. The scanning electron microscopy (SEM) analysis shows extensive cell damage leading to cracking, fragmentation, and large debris in a shorter treatment time. In addition, the fatty acids profile shows that microwave irradiation method has no degrading effect on the extracted fatty acids. The extraction by microwave achieves a significantly higher yield (33.6 ± 2.6%) with only 1 min of extraction time than conventional ultrasonic extraction (20 min, 25 °C, 28.51 ± 0.8% yield) from wet Nannochloropsis oculata biomass. Next, the efficiency of the extraction method in is evaluated in terms of species variation by applying it to the algal paste of Amphora coffeaeformis, Chaetoceros gracilis, and Isochrysis galbana. The lipid content obtained from A. coffeaeformis, C. gracilis, and I. galbana is 16.27 ± 1.5, 22.31 ± 2.5, and 19.87 ± 2.4%, respectively. Thus, the microwave method is successfully applied to algal paste. Practical Applications: The microalgal cell wall disruption is an important and complex stage and effective methods of disruption are fundamental to extracting lipids. This study shows an easy, quick, and efficient microwave method for application in routine laboratory extraction of lipids from wet microalgae pastes. A microwave compact instrument is used and the ideal condition is 1 min of microwave irradiation. The method proves to be robust against variation in mass achieved and significantly higher yield in a shorter time than ultrasonic extraction (conventional method). The microalgal cell disruption is an important and complex stage. The use of microwaves to induce cell disruption in wet biomass proves to be efficient for lipid extraction with only 1 min of extraction time. The method is applied successfully to wet microalgae pastes with different cell walls and the microwave radiation does not degrade the extracted fatty acids.

Microalgae, due to its rapid growth, low nutritional requirements, and versatility of adaptation to different environmental conditions, has aroused the biotechnological interest, synthesizing novel molecules with antioxidant, anticoagulant, anti‐inflammatory, antitumor, and antimicrobial activities. In this sense, we carried out the bioprospection of Chaetoceros muelleri, a marine diatom employed in aquaculture, as a candidate to the development of new drugs for the treatment of bacterial infections. The chemical profile of extracts in different solvents (hexane, chloroform, methylene chloride, ethyl acetate, methanol, and acetone) were analyzed by 1H‐NMR. The hexane extract was the most active against all bacteria species tested, including Mycobacterium tuberculosis, with a minimum inhibitory concentration of 100 μg/ml. Contrarily, the methanol extract was inactive against all tested microorganisms and, in addition, was the only one with IC50 >800 μg/mL, showing no cytotoxicity in VERO cell lines. All other extracts showed antibacterial potential and IC50 values varying between 267.58 and 142.47 μg/ml. The fact that C. muelleri is a microalga easily grown on bioreactors on a large scale may promote its biotechnological use, especially as scaffolds for the development of new compounds against bacterial species of clinical and public health interest.