Improvement of microalgae lipid productivity and quality in an ion-exchange-membrane photobioreactor using real municipal wastewater

To improve the productivity and quality of microalgae-based biodiesel when using municipal wastewater(MW)as nutrients source,an ion-exchange-membrane photobioreactor(IEM-PBR)was used in this study to eliminate the negative effects of pollutants in MW on microalgae Chlorella vulgaris and Scenedesmus obliquus.In the IEM-PBR,the real MW and microalgae cultures were separated in two chambers by the ion-exchange-membranes(IEMs).Nutrients(N,P,etc.)in the MW permeated into microalgae cultures through the IEMs,while pollutants(suspended solids,competitors,etc.)in the MW could hardly permeate into microalgae cultures.As a result,the lipid productivity in the IEM-PBR was improved to 85.7 mg/(L·d)for C.vulgaris and 111.8 mg/(L·d)for S.obliquus,which was slightly higher than that in the traditional photobioreactor(T-PBR)with real MW after centrifugation(82.5 mg/(L·d)for C.vulgaris and 105.8 mg/(L·d)for S.obliquus),but much higher than that in the T-PBR with untreated MW and primary MW(with lipid productivity of 20-30 mg/(L·d)).Besides,the lipid quality obtained in the IEM-PBR had higher proportion of cetane number(ca.60%)and lower linolenic acid content(ca.8%),which showed a superior quality in the IEM-PBR to that in the T-PBR.It demonstrated that the IEM-PBR is an effective approach to improve the productivity and quality of microalgae biodiesel.

Phase-feeding strategy for Chlorella vulgaris to enhance biomass and lipid productivity

A phase-feeding strategy of nutrients based on requirements of Chlorella vulgaris in different physiological phases was examined to maximize the biomass and lipid productivity.This strategy includes reduction of duration in adaption phase(stage-I),enhancement of biomass in growth phase(stage-II)and improvement of lipid productivity in stationary phase(stage-III).The duration of microalgae in adaption phase was reduced from 52 h to 34 h at nitrogen and phosphorus feeding rates of 5.11 mg/(L·d)and 0.54 mg/(L·d),whereas the maximum biomass concentration during growth phase was improved to(4.03±0.25)g/L at nitrogen and phosphorus feeding rates of 20.04 mg/(L·d)and 4.21 mg/(L·d).In stationary and decline phases,a maximum lipid productivity of 132.30 mg/(L·d)was achieved when nutrients supply was stopped at 128 h,which was 28.86 mg/(L·d)higher than that when nutrients supply was stopped at 104 h.This multi-phase cultivation could be a promising strategy for simultaneous enhancement of microalgae biomass and lipid productivity.

Lipid Accumulation Product: Reliable Marker for Cardiovascular Risk Detection?

The Lipid Accumulation Product (LAP) is a clinical marker of visceral obesity and has been proposed as a simple, inexpensive, and accurate tool to estimate cardiovascular risk and mortality. The aim of this study was to verify the association of LAP with anthropometric, biochemical, visceral adiposity index and IR in adults and the elderly. This single cross-section center clinical study, with experimental, analytical, primary, and observational design, included 210 participants. Anthropometric (Body Mass Index (BMI), Waist Circumference (WC), and Neck Circumference (NC)), LAP, Visceral Adipose Index (VAI), and biochemical parameters (fasting glycemia, insulinemia (to calculate the Homa-IR index), total cholesterol, LDL-c, HDL-c, and triglycerides) were evaluated. The results showed that by separating the sample into three groups (adequate BMI and WC, adequate BMI and elevated WC, and elevated BMI and WC), the group with high BMI and WC showed a high value of LAP and VAI compared to the other groups, with a significant difference. Still, the data show a positive and significant correlation when relating the LAP with VAI, HOMA-IR, BMI, WC, NC, total cholesterol, triglycerides, and Diastolic Blood Pressure. It also showed an inversely proportional relationship when associating LAP with HDL-c (p < 0.0001). Thus, we show that LAP is closely related to visceral adiposity, IR, altered lipid parameters, and blood pressure, especially diastolic in the patients included in our study. For these reasons, we suggest that LAP is a reliable indicator of promising visceral adiposity for early detection of cardiovascular risk in the adult and senior population.

Improvement of Medium Composition and Utilization of Mixotrophic Cultivation for Green and Blue Green Microalgae towards Biodiesel Production

A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCM), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. Moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. Meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·g&#451·d&#451).

The scope for manipulating the polyunsaturated fatty acid content of beef:a review

Since 1950, links between intake of saturated fatty acids and heart disease have led to recommendations to limit consumption of saturated fatty acid-rich foods, including beef. Over this time, changes in food consumption patterns in several countries including Canada and the USA have not led to improvements in health. Instead, the incidence of obesity, type II diabetes and associated diseases have reached epidemic proportions owing in part to replacement of dietary fat with refined carbohydrates. Despite the content of saturated fatty acids in beef, it is also rich in heart healthy cis-monounsaturated fatty acids, and can be an important source of long-chain omega-3（n-3） fatty acids in populations where little or no oily fish is consumed. Beef also contains polyunsaturated fatty acid biohydrogenation products,including vaccenic and rumenic acids, which have been shown to have anticarcinogenic and hypolipidemic properties in cell culture and animal models. Beef can be enriched with these beneficial fatty acids through manipulation of beef cattle diets, which is now more important than ever because of increasing public understanding of the relationships between diet and health. The present review examines recommendations for beef in human diets, the need to recognize the complex nature of beef fat, how cattle diets and management can alter the fatty acid composition of beef, and to what extent content claims are currently possible for beef fatty acids.

Utilization of Soluble Starch by Oleaginous Red Yeast Rhodotorula glutinis

Starch containing wastewaters from the food and feed industry have been identified as potential cheap carbon sources for the production of microbial lipids. Due to its high potential lipid content the oleaginous yeast Rhodotorula glutinis is often used for fermentations in this field. Moreover it is investigated in the context of microbial carotenoid production, which also requires a cheap source of carbon. Thus, the ability of R. glutinis (ATCC 15125TM) to degrade and utilize soluble starch for the production of lipids has been assessed in this study. While glucose and fructose were readily consumed from the medium, starch was only slightly reduced in one treatment. The yield of fatty acid methyl esters (FAME) was graduated corresponding to the initial sugar contents, with the highest FAME yield (1.5 g·L-1) at the highest initial sugar content. In the treatment that contained starch as single carbon source, no FAME production was realized. Accordingly, if starchy wastewaters should be used for microbial cultivation with R. glutinis, an enzymatic or chemical pretreatment for starch hydrolysis should be applied, to increase the availability of this carbon source.

Comparative study on cultivation of microalgae for nutrient removal and lipid production in different artificial wastewaters

Wastewater contains high concentration of nutrients,like nitrogen and phosphorus,which have been identified as the main reasons for water eutrophication and serious ecological issues.Therefore,cultivating a tolerant and adaptive microalgae strain in wastewater is considered as a promising approach for sustainable biomass/lipid production.The potential usages of Desmodesmus sp.for biomass and lipid production within different artificial wastewater(AW)were investigated and the removal efficiencies of nutrient were compared.The maximum removal rate of chemical oxygen demand,ammonia nitrogen,nitrate nitrogen and phosphate were 272 mg/(L·d),14.021 mg/(L·d),7.774 mg/(L·d)and 3.347 mg/(L·d),respectively in AW2,AW3,AW5 and AW2.Maximum biomass(1.159 g/L)and lipid(280 mg/L)productions were observed in AW5,while the highest lipid content achieved was 37.42%in AW1.Fatty acid analysis showed that lipids extracted from AW-cultivated Desmodesmus sp.contained 59.57%-77.79%polyunsaturated fatty acids(30.6%-44.47%was linoleic acid).