Evaluation of animal- and plant-based lipidic waste in anaerobic digestion: kinetics of long-chain fatty acids degradation.

Recently, lipidic wastes have been reported to enhance biomethane production through anaerobic co-digestion (ACD). These lipidic wastes were of animal and plant origins. The comparison of animal and plant lipidic wastes with the microbial communities involved in lipid degradation have not been given adequate attention in pervious reviews. However, there is need to demonstrate the differences between these wastes in terms of their long-chain fatty acids (LCFAs) composition, nature, and availability. This review discusses the characterization and comparison of animal and plant lipidic wastes as co-substrates, while summarizing the potential of biomethane production in the laboratory, as well as pilot and full-scale operations. The degradation kinetics of LCFAs existing in animal and plant lipidic wastes were also highlighted during the operation process, along with the challenges (such as inhibition by LCFAs, sludge washout, sludge flotation, and foaming). Discussion on the use of the next gene sequencing (NGS) for the microbial community in the ACD of lipidic wastes was considered to understand the interspecies interactions among various microbes. The economic feasibility of lipidic wastes in the ACD along with biogas yield has also been evaluated. The use of lipids (animal and plant based) in anaerobic digestion with the application of combined pretreatment or an acclimatized microbial consortium could be a potential approach for maximum energy recovery from the waste in terms of biomethane production.

Evaluation of Chlorella sorokiniana isolated from local municipal wastewater for dual application in nutrient removal and biodiesel production.

The isolated microalga Chlorella sorokiniana BENHA721_ABO4 was grown in Bold's basal medium (BBM) as a control, municipal wastewater (WW), and wastewater enriched with BBM elements (WW+). Cultivation in WW+ showed the highest cell number which represented 25.3 and 47.3% over that grown in WW and BBM, respectively. However, rapid growth in WW+ was accompanied by significant reduction in lipid content. Due to lipid accumulation in WW, it showed the maximum significant lipid productivity of 16.2 mg L-1 day-1. Microalgae cultivation in WW for 10 days showed 74.2, 83.3, and 78.0% removal efficiency for NO3-N, NH3-N and TP, respectively. In addition, growth in WW significantly reduced polyunsaturated fatty acids by 36.0% with respect to BBM in favor of monounsaturated fatty acids. The present results confirmed that C. sorokiniana isolate BENHA721_ABO4 grown in secondary effluent municipal wastewater offers real potential for future application in wastewater treatment and biodiesel production.

Applications of Non-destructive Technologies for Agricultural and Food Products Quality Inspection.

The quality and safety of food is an increasing concern for worldwide business. Non-destructive methods (NDM), as a means of assessment and instrumentation have created an esteemed value in sciences, especially in food industries. Currently, NDM are useful because they allow the simultaneous measurement of chemical and physical data from food without destruction of the substance. Additionally, NDM can obtain both quantitative and qualitative data at the same time without separate analyses. Recently, many studies on non-destructive detection measurements of agro-food products and final quality assessment of foods were reported. As a general statement, the future of using NDM for assessing the quality of food and agricultural products is bright; and it is possible to come up with interesting findings through development of more efficient and precise imaging systems like the machine vision technique. The present review aims to discuss the application of different non-destructive methods (NDM) for food quality and safety evaluation.

Influence of nutrient supplementation and starvation conditions on the biomass and lipid productivities of Micractinium reisseri grown in wastewater for biodiesel production.

Generation of biodiesel from microalgae grown in wastewater can offer a cost-effective approach, whilst wastewaters usually do not contain the optimum concentrations of the essential nutrients and carbon sources that result in lowering the productivities of biomass and lipid. This study aimed to overcome this limitation by manipulating wastewater with various concentrations of nutrients (NO3-, PO43-, Cl- and SO42-) and three carbon sources either individually or in combination to cultivate Micractinium reisseri for biodiesel production. Initially, various dilutions of wastewater were tested and a concentration up to 75% of wastewater showed the highest biomass productivity (0.076 g L-1 d-1) and lipid productivity (0.014 g L-1 d-1). The optimum manipulating conditions for maximum lipid production and the highest productivity required 50% decrease in phosphorous from the concentration of the control medium and supplementation with 1.0 g L-1 of glucose. Under this condition, biomass and lipid productivities increased by 1.7 and 4-folds, respectively, compared to those observed in the control. Furthermore, phosphorous starvation condition in the presence of glucose significantly improved fatty acid profile in the biomass and biodiesel quality related parameters.

Cloning and Functional Analysis of Phosphoethanolamine Methyltransferase Promoter from Maize (Zea mays L.).

Betaine, a non-toxic osmoprotectant, is believed to accumulate considerably in plants under stress conditions to maintain the osmotic pressure and promote a variety of processes involved in growth and development. Phosphoethanolamine N-methyltransferase (PEAMT), a key enzyme for betaine synthesis, is reported to be regulated by its upstream promoter. In the present investigation, by using the transgenic approach, a 1048 bp long promoter region of ZmPEAMT gene from Zea mays was cloned and functionally characterized in tobacco. Computational analysis affirmed the existence of abiotic stress responsive cis-elements like ABRE, MYC, HST, LST etc., as well as pathogen, wound and phytohormone responsive motifs. For transformation in tobacco, four 5'-deletion constructs of 826 bp (P2), 642 bp (P3), 428 bp (P4) and 245 bp (P5) were constructed from the 1048 bp (P1) promoter fragment. The transgenic plants generated through a single event exhibited a promising expression of GUS reporter protein in the leaf tissues of treated with salt, drought, oxidative and cold stress as well as control plants. The GUS expression level progressively reduced from P1 to P5 in the leaf tissues, whereas a maximal expression was observed with the P3 construct in the leaves of control plants. The expression of GUS was noted to be higher in the leaves of osmotically- or salt-treated transgenic plants than that in the untreated (control) plants. An effective expression of GUS in the transgenic plants manifests that this promoter can be employed for both stress-inducible and constitutive expression of gene(s). Due to this characteristic, this potential promoter can be effectively used for genetic engineering of several crops.

Macroalgal activity against multiple drug resistant Aeromonas hydrophila: A novel treatment study towards enhancement of fish growth performance.

OBJECTIVE: The aim of this study was to evaluate the efficiency of macroalgal extracts as antibacterial agent against multidrug-resistant (MDR) bacteria isolated from Nile tilapia (Oreochromis niloticus) as well as to enhance the fish growth performance by macroalgae diet application. METHODS: A total of 50 swabs were collected from the diseased organs of tilapia fish including gills, skin, spleen, intestine, liver, kidney and muscle. The isolated bacteria were identified and then confirmed by using VITEK 2. Eight macroalgal species were collected from Abu-Qir, Alexandria coast, Egypt. After determination of their biomass, three solvents were used to prepare algal extracts. The antibacterial activities of different macroalgal extracts were measured against MDR Aeromonas hydrophila 6 (MDRAH6) using well-diffusion method. The mechanism by which macroalgal extract affects MDR bacteria was conducted by using transmission electron microscope (TEM). To evaluate the safety of the promising algal extract, GC-MS was performed to detect the composition of S. vulgare extract. In addition, growth performance was measured as an application of algal extracts into fish feed. RESULTS: Between eight collected macroalgal species, Sargassum vulgare showed the highest biomass production (53.4 g m-2). In addition, its ethanolic extract showed the highest significant antibacterial activity with MIC value of 250 µg ml-1. TEM examination showed distinctive changes in the treated MDRAH6 cells including rupture of the cell wall, leakage of cytoplasmic contents, alterations in the cytoplasm density in addition to totally cell deformation. In addition, GC-MS analysis revealed eleven identified components in S. vulgare ethanolic extract, in which 9,12-octadecadienoyl chloride and hexadecanoic acid methyl ester were dominant (46.6 and 19.7 %, respectively). Furthermore, dietary replacement of fish meal with S. vulgare ethanolic extract significantly enhanced the growth performance and survival of Nile tilapia with a significant reduction in the total bacterial count. CONCLUSION: Ethanol extract of the brown macroalga S. vulgare could be a promising antibacterial and a new active agent against MDR A. hydrophila, which could be a major causative agent of Nile tilapia fish diseases. In addition, this study recommended S. vulgare as a natural and effective source to enhance the growth performance of Nile tilapia. In fact, isolation and examination of the individual antibacterial active compounds of the S. vulgar ethanolic extract are under investigation.

Optimization of aeration for biodiesel production by Scenedesmus obliquus grown in municipal wastewater.

Despite the significant breakthroughs in research on microalgae as a feedstock for biodiesel, its production cost is still much higher than that of fossil diesel. One possible solution to overcome this problem is to optimize algal growth and lipid production in wastewater. The present study examines the optimization of pretreatment of municipal wastewater and aeration conditions in order to enhance the lipid productivity of Scenedesmus obliquus. Results showed that no significant differences were recorded in lipid productivity of S. obliquus grown in primary settled or sterilized municipal wastewater; however, ultrasound pretreatment of wastewater significantly decreased the lipid production. Whereas, aeration rates of 0.2 vvm significantly increased lipid content by 51 %, with respect to the non-aerated culture, which resulted in maximum lipid productivity (32.5 mg L(-1) day(-1)). Furthermore, aeration enrichment by 2 % CO2 resulted in increase of lipid productivity by 46 % over the CO2 non-enriched aerated culture. Fatty acid profile showed that optimized aeration significantly enhanced monounsaturated fatty acid production, composed mainly of C18:1, by 1.8 times over the non-aerated S. obliquus culture with insignificant changes in polyunsaturated fatty acid proportion; suggesting better biodiesel characteristics for the optimized culture.

Extracellular secretion of free fatty acids by the chrysophyte Ochromonas danica under photoautotrophic and mixotrophic growth.

Recently, microalgae have gained a lot of attention because of their ability to produce fatty acids in their surrounding environments. The present paper describes the influence of organic carbon on the different fatty acid pools including esterified fatty acids, intracellular free fatty acids and extracellular free fatty acids in Ochromonas danica. It also throws light on the ability of O. danica to secrete free fatty acids in the growth medium under photoautotrophic and mixotrophic conditions. Biomass production of photoautotrophically grown O. danica was higher than that of mixotrophically grown, where a cellular biomass formation of 1.8 g L(-1) was observed under photoautotrophic condition which was about five folds higher than that under mixotrophic conditions. Contrary, the esterified fatty acid content reached up to 99 mg g(-1) CDW under photoautotrophic conditions at the late exponential phase, while during mixotrophic conditions a maximum of 212 mg g(-1) CDW was observed at the stationary phase. Furthermore, O. danica cells grown under mixotrophic conditions showed higher intracellular free fatty acid and extracellular free fatty acid contents (up to 51 and 20 mg g(-1) CDW, respectively) than cells grown under photoautotrophic conditions (up to 26 and 4 mg g(-1) CDW, respectively). The intra- and extracellular free fatty acids consisted of a high proportion of polyunsaturated fatty acids, mainly C18:2n-6, C18:3n-3 and C20:4n-6.

Optimization of biomass and fatty acid productivity of Scenedesmus obliquus as a promising microalga for biodiesel production.

Nowadays, microalgae are discussed as a promising feedstock for biodiesel production. The present study examines the possibility of enhancement of fatty acid productivity of Scenedesmus obliquus by modifications of the culture medium composition. The effect of different concentrations of sodium bicarbonate, salinity, potassium nitrate, glycerol and sugarcane molasses on the enhancement of biomass and esterified fatty acids production was studied. NaHCO3 caused an increase in the biomass productivity at low concentrations (0.5 g L(-1)), while negatively affected fatty acid productivity at all tested concentrations. Increase of salinity enhanced both biomass and fatty acid productivity. The optimum NaCl concentration and sea water ratio were 0.94 g L(-1) and 25 % which resulted in 56 and 39 % increase in fatty acid productivity, respectively. Nitrogen deficiency showed increase in fatty acid content by 54 % over control but fatty acid productivity was decreased as a result of growth inhibition. Nitrogen-free cultures and cultures treated with -50 % concentrations of KNO3 showed 96 and 42 % decrease in EFA productivity, respectively, as compared with the control. Addition of 0.05 and 0.1 M of glycerol increased the biomass productivity by 6 and 5 %, respectively but showed no significant effect on fatty acid productivity as a result of decrease in fatty acid content. Finally, usage of sugarcane molasses stimulated both biomass and fatty acid content. The increase in fatty acid productivity was 32, 65 and 73 % above the control level at 1, 3 and 5 g L(-1) of sugarcane molasses, respectively.

Progress in biohythane production from microalgae-wastewater sludge co-digestion: An integrated biorefinery approach.

Recent advances in microalgae to biohythane (bio-H2 and bio-CH4) conversion have achieved growing attention due to their eco-friendly and energy-efficient nature. Although microalgae are considered a potential 3rd - 4th generation biomass, their low C/N ratio and cell-wall biopolymers are challenging for biohythane production. This study emphasizes the solutions to mitigate the adverse effects of microalgae-based biohythane production using co-digestion with wastewater sludge. Wastewater sludge, an emerging environmental concern, is reviewed to be an effective co-substrate with microalgae to establish a biorefinery approach. The future trends and prospects of this biorefinery approach is critically reviewed to attain a profitable process. This study also reviewed the advantages of microalgae-wastewater co-cultivation and the application of activated sludge for bio-flocculation as a cost-effective solution for microalgae cultivation and harvesting. Microalgae-wastewater co-cultivation is also recommended to be effective for biohythane purification. The liquid digestate is suggested to be used as a culture media to enhance microalgal growth; whereas, the solid digestate could be transformed into resources through hydrothermal processes as a solution of digestate management. A practical biorefinery approach combining the synergistic benefits of microalgae-wastewater sludge and its biological conversion to biohythane would be an adjoining link to the beginning of a sustainable future.

Enhanced methane production coupled with livestock wastewater treatment using anaerobic membrane bioreactor: Performance and membrane filtration properties.

The present study introduced a new method for enhanced biomethane production and pollution control of swine wastewater (SW) using anaerobic membrane bioreactor (AnMBR). Results confirmed 35 °C as the optimum temperature for enhanced anaerobic digestion which resulted in relatively higher methane production rate and potential. In AnMBR system, robust pollutants removal and conversion rate were achieved under various hydraulic retention time (HRT) ranging from 20 to 10 days, while the highest methane yield (0.24 L/g-CODremoved) and microbial activity (6.65 mg-COD/g-VSS·h) were recorded at HRT of 15 days. Reduction of HRT to 10 days resulted in serious membrane fouling due to accumulation of extracellularpolymericsubstances(EPS) and cake layer on the membrane. However, cake layer as the dominant membrane foulant could be effectively removed through periodic physical backwash to recover the membrane permeability. Overall, the suggested AnMBR is a promising technology to enhance SW treatment and energy recovery.

Commercial Seaweed Liquid Extract as Strawberry Biostimulants and Bioethanol Production.

Seaweeds are increasingly intriguing as a sustainable source of bioactive compounds. They have applications in agriculture, fuels, feed, and food products. To become a cost-competitive product with zero waste, a biorefinery approach is applied, where several products are valorized at the same time. True-Algae-Max (TAM®) has been investigated for its ability to improve the yield and nutritional facts of a strawberry plant. Three concentrations of TAM (0, 50, and 100%) were examined by foliar spray in 2017 with 50% NPK chemical fertilizer. Results indicated that growth, yield, chlorophyll, and potassium content were significantly improved by TAM treatments. TAM50 % resulted in maximum root length, leaf area, plant fresh weight, fruit weight, and yield with an increase ranging from 10 to 110% compared to control. Compared to the NPK control, strawberries grown with TAM50% improved total soluble solids (TSS) from 7.58 to 10.12% and anthocyanin from 23.08 to 29.42 mg CGE 100 g-1. Noteworthily, this reduced total sugar, and total phenolics were boosted by TAM applications, while non-reducing sugar was reduced compared to control. On the other hand, whole seaweed biomass and TAM residuals were used for bioethanol production by acid scarification. The maximum bioethanol yield was observed in residual biomass (0.34 g g-1 dw), while the whole seaweed biomass showed only 0.20 g g-1 dw. These results proved the biorefinery concept of using seaweed extract as a biostimulator and bioethanol production.

Valorization of lipidic food waste for enhanced biodiesel recovery through two-step conversion: A novel microalgae-integrated approach.

The present study designed an innovative route for two-step biodiesel recovery from lipidic food waste followed by microalgae cultivation. Optimization of oil conversion showed the highest fatty acid methyl esters (FAMEs) recovery of 92.6% (lipid basis). Microalgal lipid accumulation enhanced by the increased lipid-free waste hydrolysate ratio in the medium, where the maximum lipid content of 26.2 dw% was recorded using 50% hydrolysate. Application of 30% hydrolysate ratio resulted in the maximum recorded lipid productivity, which was 99.4% higher than that of the control and insignificant with 40% hydrolysate. Waste oil-derived FAMEs showed 69.0% higher saturated fatty acids (SFAs) proportion than that of algal lipids. In contrast, the highest polyunsaturated fatty acids (PUFAs) proportion (48.8% of total fatty acids) was recorded in microalgal lipids. The study concluded that mixing microalgal lipids with waste oil (1:1, w/w) provides a desirable practical route for enhanced biodiesel production complying with the international standards.

Enhancement of biodiesel yield and characteristics through in-situ solvo-thermal co-transesterification of wet microalgae with spent coffee grounds.

This study evaluated in-situ co-transesterification of wet spent coffee ground (SCG)/microalgae mixture for enhanced biodiesel production. SCG and microalgae showed lipid contents of 16.0 and 23.6 wt%, respectively. A total of 27 transesterification runs were performed using wet SCG:algae (1:1, w/w) at different temperatures, times, and solvent ratios. Box-Behnken quadratic model suggested 198 °C, 6 mL solvent g-1 biomass, and reaction time of 132 min as the optimum conditions for maximum biodiesel yield. At different SCG/microalgae blend ratios, pure microalgae showed the highest biodiesel yield of 20.15 wt%. Increase of SCG ratio resulted in significant reduction in the biodiesel yield, reaching the lowest value of 11.2 wt% using pure SCG. On the other hand, SCG showed better biodiesel characteristics than microalgae regarding iodine value, cetane number, and oxidation stability. The present results confirmed that SCG-algae blend results in dual effect of enhancing biodiesel yield and quality, comparing to the individual transesterification.

A novel bifunctional aldehyde/alcohol dehydrogenase catalyzing reduction of acetyl-CoA to ethanol at temperatures up to 95 °C.

Hyperthermophilic Thermotoga spp. are excellent candidates for the biosynthesis of cellulosic ethanol producing strains because they can grow optimally at 80 °C with ability to degrade and utilize cellulosic biomass. In T. neapolitana (Tne), a putative iron-containing alcohol dehydrogenase was, for the first time, revealed to be a bifunctional aldehyde/alcohol dehydrogenase (Fe-AAdh) that catalyzed both reactions from acetyl-coenzyme A (ac-CoA) to acetaldehyde (ac-ald), and from ac-ald to ethanol, while the putative aldehyde dehydrogenase (Aldh) exhibited only CoA-independent activity that oxidizes ac-ald to acetic acid. The biochemical properties of Fe-AAdh were characterized, and bioinformatics were analyzed. Fe-AAdh exhibited the highest activities for the reductions of ac-CoA and acetaldehyde at 80-85 °C, pH 7.54, and had a 1-h half-life at about 92 °C. The Fe-AAdh gene is highly conserved in Thermotoga spp., Pyrococcus furiosus and Thermococcus kodakarensis, indicating the existence of a fermentation pathway from ac-CoA to ethanol via acetaldehyde as the intermediate in hyperthermophiles.

Life Cycle Assessment and Impact Correlation Analysis of Fly Ash Geopolymer Concrete.

Geopolymer concrete (GPC) has drawn widespread attention as a universally accepted ideal green material to improve environmental conditions in recent years. The present study systematically quantifies and compares the environmental impact of fly ash GPC and ordinary Portland cement (OPC) concrete under different strength grades by conducting life cycle assessment (LCA). The alkali activator solution to fly ash ratio (S/F), sodium hydroxide concentration (CNaOH), and sodium silicate to sodium hydroxide ratio (SS/SH) were further used as three key parameters to consider their sensitivity to strength and CO2 emissions. The correlation and influence rules were analyzed by Multivariate Analysis of Variance (MANOVA) and Gray Relational Analysis (GRA). The results indicated that the CO2 emission of GPC can be reduced by 62.73%, and the correlation between CO2 emission and compressive strength is not significant for GPC. The degree of influence of the three factors on the compressive strength is CNaOH (66.5%) > SS/SH (20.7%) > S/F (9%) and on CO2 emissions is S/F (87.2%) > SS/SH (10.3%) > CNaOH (2.4%). Fly ash GPC effectively controls the environmental deterioration without compromising its compressive strength; in fact, it even in favor.

Integrated approach for enhanced bio-oil recovery from disposed face masks through co-hydrothermal liquefaction with Spirulina platensis grown in wastewater.

Currently, the enormous generation of contaminated disposed face masks raises many environmental concerns. The present study provides a novel route for efficient crude bio-oil production from disposed masks through co-hydrothermal liquefaction (Co-HTL) with Spirulina platensis grown in wastewater. Ultimate and proximate analysis confirmed that S. platensis contains relatively high nitrogen content (9.13%dw), which decreased by increasing the mask blend ratio. However, carbon and hydrogen contents were higher in masks (83.84 and 13.77%dw, respectively). In addition, masks showed 29.6% higher volatiles than S. platensis, which resulted in 94.2% lower ash content. Thermal decomposition of masks started at a higher temperature (≈330 °C) comparing to S. platensis (≈208 °C). The highest bio-oil yield was recorded by HTL of S. platensis and Co-HTL with 25% (w/w) masks at 300 °C, which showed insignificant differences with each other. GC/MS analysis of the bio-oil produced from HTL of algal biomass showed a high proportion of nitrogen- and oxygen-containing compounds (3.6% and 11.9%, respectively), with relatively low hydrocarbons (17.4%). Mask blend ratio at 25% reduced the nitrogen-containing compounds by 55.6% and enhanced the hydrocarbons by 43.7%. Moreover, blending of masks with S. platensis enhanced the compounds within the diesel range in favor of gasoline and heavy oil. Overall, the present study provides an innovative route for enhanced bio-oil production through mask recycling coupled with wastewater treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13399-021-01891-2.

Potential Applications of Arthrospira platensis Lipid-Free Biomass in Bioremediation of Organic Dye from Industrial Textile Effluents and Its Influence on Marine Rotifer (Brachionus plicatilis).

Arthrospira platensis is one of the most important cultured microalgal species in the world. Arthrospira complete dry biomass (ACDB) has been reported as an interesting feedstock for many industries, including biodiesel production. The A. platensis by-product of biodiesel production (lipid-free biomass; LFB) is a source of proteins, functional molecules, and carbohydrates, and can also be reused in several applications. The current study investigated the efficiency of ACDB and LFB in bioremediation of dye (Ismate violet 2R, IV2R) from textile effluents. In addition, the potential of ACDB and LFB loaded by IV2R as a feed for Rotifer, Brachionus plicatilis, was examined. The surface of the adsorbents was characterized by SEM, FTIR, and Raman analysis to understand the adsorption mechanism. The batch sorption method was examined as a function of adsorbent dose (0.02-0.01 g L-1), solution initial concentration (10-100 mg L-1), pH (2-10), and contact time (15-180 min). The kinetic studies and adsorption isotherm models (Freundlich, Langmuir, Tempkin, and Halsey) were used to describe the interaction between dye and adsorbents. The results concluded that the adsorption process increased with increasing ACDB and LFB dose, contact time (120 min), initial IV2R concentration (10 mg L-1), and acidity pH (2 and 6, respectively). For the elimination of industrial textile wastewater, the ACDB and LFB sorbents have good elimination ability of a dye solution by 75.7% and 61.11%, respectively. The kinetic interaction between dye and adsorbents fitted well to Langmuir, Freundlish, and Halsey models for LFB, and Langmuir for ACDB at optimum conditions with R2 > 0.9. In addition, based on the bioassay study, the ACDB and LFB loaded by IV2R up to 0.02 g L-1 may be used as feed for the marine Rotifer B. plicatilis.

A close-loop integrated approach for microalgae cultivation and efficient utilization of agar-free seaweed residues for enhanced biofuel recovery.

The aim of this work was to evaluate a novel integrated biorefinery route for enhanced energy recovery from seaweeds and microalgae. Agar extraction prior to anaerobic digestion recorded the highest biogas productivity of 32.57 L kg-1 VS d-1. Supplementation of the microalgal growth medium with anaerobic digestate from agar-extracted biomass enhanced the microalgal growth, recording the highest dry weight of 4.57 g L-1 at 20% digestate ratio. In addition, lipid content showed the highest value of 25.8 %dw. Due to enhancement of growth and lipid content, 20% digestate ratio showed the highest lipid productivity and FAMEs recovery (65.2 mg L-1 d-1 and 123.3 mg g-1dw, respectively), with enhanced biodiesel characteristics. The present study estimated annual revenue of 1252.7 US$ ton-1 from the whole Gracilaria multipartita biomass conversion into biogas, while that through agar extraction deserved 36087.0 US$ ton-1, with enhanced annual biodiesel yield by 69.7% over the control medium.