1.The effects of salinity on the growth and biochemical properties of Chlamydomonas mexicana GU732420 cultivated in municipal wastewater.
Salama el-S, Abou-Shanaba RA, Kim JR, Lee S, Kim SH, Oh SE, Kim HC, Roh HS, Jeon BH. Environ Technol. 2014 May-Jun;35(9-12):1491-8.
A freshwater microalga Chlamydomonas mexicana was grown on municipal wastewater with different levels of salinity up to 400 mmol/L NaCl, and the biochemical properties were characterized after 10 days of cultivation. C. mexicana showed the higher specific growth rates for 100 and 200mmol/L NaCl. Nitrogen was completely removed within 10 days as a result of algal growth promoted by the addition of 200-400 mmol/L NaCl. Phosphorus removal increased from 77-84% as the concentration of NaCI increased from 100 to 400 mmol/L. The highest removal of total inorganic carbon (66%) was obtained with the addition of 200 mmol/L NaCl. The lipid content increased from 17% to 38% as the concentration of NaCl increased from 0 to 400mmol/L. The total fatty acid content and glycerol yield of C. mexicana increased 1.8- and 4-fold in wastewater amended with NaCl, respectively. Fatty acids accumulated in the algal biomass were mainly composed of palmitic (27-29%), y-linolenic (27-30%), and linolelaidic acids (16-18%).
2.Fluorescence of N-acylated dansylamide with a long hydrophobic tail: sensitive response to premicellar aggregation of sodium deoxycholate.
Tripathi AK1, Mohapatra M, Mishra AK. Phys Chem Chem Phys. 2015 Nov 28;17(44):29985-94. doi: 10.1039/c5cp04263a. Epub 2015 Oct 23.
The present work describes the synthesis and photophysical studies of two fluorescent dansylamide derivatives, in which the amine group is acylated by a long hydrophobic chain (a part of a biologically relevant palmitic acid) and by a short hydrophobic tail (a part of acetic acid). The long chain tethered dansyl analogue is successfully utilized in estimating critical micellar concentration (CMC) of bile salts (NaDC, NaC) as well as anionic and cationic surfactants (SDS, CTAB) with the help of enhanced fluorescence intensity facilitated by better solubilization of the molecule in microheterogeneous media. The long chain tethered dansylamide derivative shows significant fluorescence solvatochromism with a red shift (ca. 4000 cm(-1)) from hexane to water. In contrast, the solvatochromism exhibited by the parent/short acyl chain analogue is much less (ca. 2230 cm(-1) from hexane to water) and the fluorescence is not sensitive to micellization.
3.Effect of food wastewater on biomass production by a green microalga Scenedesmus obliquus for bioenergy generation.
Ji MK1, Yun HS1, Park S1, Lee H1, Park YT1, Bae S2, Ham J3, Choi J4. Bioresour Technol. 2015 Mar;179:624-8. doi: 10.1016/j.biortech.2014.12.053. Epub 2014 Dec 20.
Effect of food wastewater (FW) on the biomass, lipid and carbohydrate production by a green microalga Scenedesmus obliquus cultivated in Bold's Basal Medium (BBM) was investigated. Different dilution ratios (0.5-10%) of BBM either with FW or salt solution (NaCl) or sea water (SW) were evaluated. S. obliquus showed the highest growth (0.41 g L(-1)), lipid productivity (13.3 mg L(-1) day L(-1)), carbohydrate productivity (14.7 mg L(-1) day L(-1)) and nutrient removal (38.9 mg TN L(-1) and 12.1 mg TP L(-1)) with 1% FW after 6 days of cultivation. The FW promoted algal autoflocculation due to formation of inorganic precipitates at an alkali pH. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 8% with FW. Application of FW improved the growth, lipid/carbohydrate productivity and biomass recovery efficiency of S. obliquus, which can be exploited for cost effective production of microalgae biomass.
4.Metabolomic analysis of the salt-sensitive mutants reveals changes in amino acid and fatty acid composition important to long-term salt stress in Synechocystis sp. PCC 6803.
Wang J1, Zhang X, Shi M, Gao L, Niu X, Te R, Chen L, Zhang W. Funct Integr Genomics. 2014 Jun;14(2):431-40. doi: 10.1007/s10142-014-0370-7. Epub 2014 Mar 19.
Early studies in cyanobacteria have found that few genes induced by short-term salt shock (15-60 min) display a stable induction in the long-term (>1 day) salt-acclimated cells; meanwhile, most of the genes responsive to long-term salt stress were different from those by short-term salt shock, suggesting that different regulatory mechanisms may be involved for short-term and long-term salt stress responses. In our previous work using the model cyanobacterium Synechocystis sp. PCC 6803, sll1734 encoding CO2 uptake-related protein (CupA) and three genes encoding hypothetical proteins (i.e., ssr3402, slr1339, and ssr1853) were found induced significantly after a 3-day salt stress, and the corresponding gene knockout mutants were found salt sensitive. To further decipher the mechanisms that these genes may be involved, in this study, we performed a comparative metabolomic analysis of the wild-type Synechocystis and the four salt-sensitive mutants using a gas chromatography-mass spectrometry (GC-MS) approach.