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This review includes works published in the general scientific literature during 2016 on the production of bioenergy and biofuel from waste residues generated during bioethanol and biodiesel production with a brief overview of current and emerging feedstocks. A section of this review summarizes literature on culturing algae for biofuels including bioreactors and open pond cultivation systems with the utilization of inorganic and organic sources of nutrients. New methods applicable to the mass culture of algae are highlighted. Algal cell harvesting and oil extraction techniques are discussed along with policies and economics. [ABSTRACT FROM AUTHOR]

Use of oleaginous microorganisms as 'micro-factories' for accumulation of single cell oils for biofuel production has increased significantly to mitigate growing energy demands, resulting in efforts to upgrade industrial waste, such as second-generation lignocellulosic residues, into potential feedstocks. Dilute-acid pretreatment (DAP) is commonly used to alter the physicochemical properties of lignocellulosic materials and is typically coupled with simultaneous saccharification and fermentation (SSF) for conversion of sugars into ethanol. The resulting DAP residues are usually processed as a waste stream, e.g. burned for power, but this provides minimal value. Alternatively, these wastes can be utilized as feedstock to generate lipids, which can be converted to biofuel. DAP-SSF residues were generated from pine, poplar, and switchgrass. High performance liquid chromatography revealed less than 0.13% monomeric sugars in the dry residue. Fourier transform infrared spectroscopy was indicative of the presence of lignin and polysaccharides. Gel permeation chromatography suggested the bacterial strains preferred molecules with molecular weight ~ 400-500 g/mol. DAP-SSF residues were used as the sole carbon source for lipid production by Rhodococcus opacus DSM 1069 and PD630 in batch fermentations. Depending on the strain of Rhodococcus employed, 9-11 lipids for PD630 and DSM 1069 were observed, at a final concentration of ~ 15 mg/L fatty acid methyl esters (FAME) detected. Though the DAP-SSF substrate resulted in low FAME titers, novel analysis of solid-state fermentations was investigated, which determined that DAP-SSF residues could be a viable feedstock for lipid generation. [ABSTRACT FROM AUTHOR]

Diatoms are responsible for up to 40% of the carbon fixation in our oceans. The fixed carbon is moved through carbon metabolism towards the synthesis of organic molecules that are consumed through interlocking foodwebs, and this process is strongly impacted by the abiotic environment. However, it has become evident that diatoms can be used as 'platform' organisms for the production of high valuable bio-products such as lipids, pigments and carbohydrates where stress conditions can be used to direct carbon metabolism towards the commercial production of these compounds. In the first section of this review, some aspects of carbon metabolism in diatoms and how it is impacted by environmental factors are briefly described. The second section is focused on the biosynthesis of lipids and in particular omega-3 long-chain polyunsaturated fatty acids and how low temperature stress impacts on the production of these compounds. In a third section, we review the recent advances in bioengineering for lipid production. Finally, we discuss new perspectives for designing strains for the sustainable production of high-value lipids. [ABSTRACT FROM AUTHOR]

This paper reviews some of the most important aspects of microalgae as a potential source for biodiesel production. Microalgae are photosynthetic microorganisms that can grow rapidly in a variety of environments because of their unicellular or multicellular structure depending on the species. They have the advantage of self-reproduction using solar energy and converting it into chemical energy via photosynthesis. This process concludes a full cycle in a few days, obtaining higher lipid yields than terrestrial crops. This review shows several techniques and some methodologies used in the biodiesel production process from microalgae as well as the challenges that must be overcome for large-scale process and in bio-refineries. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The paper is dedicated to new unconventional sources of non-food renewable feedstock for third generation biofuel – microalgae biomass. Methods of lipid induction in microalgae have been considered. It represents the results of advanced microalgae strains state-of-the-art investigations – lipid producers. The paper discusses selection of stressors at two-stage culturing, where 1st stage includes culturing under most optimal conditions to produce maximum amount of biomass, and at 2nd stage biosynthesis and accumulation of lipids in biomass occurs. Types of stressors used for lipid induction have been briefly reviewed on the basis of foreign studies. Proper experimental results on isolation of new candidate microalgae strains from natural sources, as well as on selection of stressors for lipid induction have been shown and discussed. Nitrogen and phosphoric starvation, high and low illuminance, along with temperature conditions have been studied as stressors. Effectiveness of lipid-containing microalgae screening technique by fluorescent dye Nile red staining has been determined. Processible fast-growing Arhtrospira platensis microalgae/cyanobacteria use perspectiveness as a model for selection of stressors and overall lipid-containing microalgae culturing mode have been verified. Method of various microalgae heat-treated biomass conversion into biohydrogen by anaerobic acetone-butanol fermentation using cellular immobilized catalysts based on Clostridium acetobutylicum has been considered. Ultimate hydrogen efficiency has been found for Chlorococcum sp. rsemsu Ccc-7/11 strain biomass (8.4 и 6.1 mmol/l of medium/day); while hydrogen production is 23.7% and 18.6% of notionally possible level, A. platensis strains cultivated under the influence of stressors ( rsemsu 1/02-P – 5.6 mmol/l of medium/day, 32.3%; rsemsu 1/02-Т – 3.3 mmol/of medium/day, 28.8%) rank slightly below them in efficiency, outperforming in hydrogen production. [ABSTRACT FROM AUTHOR]

The present study was conducted with microalga Nannochloropsis sp. to evaluate its tolerance responses and biofuel perspectives under different arsenic regime (0–1000 μM As(III)). Results showed that optimal biomass (61.00 ± 3.72 mg/L/d) and lipid productivity (20.27 mg/L/d) were obtained in culture treated with 100 μM As(III) in comparison to other treatments. In addition, fatty acid profile of alga was in accordance with European biodiesel standards (EN 14214), which reflects good oxidative stability of oil. High antioxidants viz., ascorbic acid, GSH and cysteine tolerance responses as well as lipid yield at 100 μM As(III), opens a new insight in the field of algal biology. Thus, microalgae Nannochloropsis sp. may be employ in remediation as well as biodiesel production. [ABSTRACT FROM AUTHOR]

An integrated screening approach was developed to assess the potential of the Botryococcus genus for the production of lipids for biofuel application (hydrocarbons and triacylglycerols). The strategy developed in this study permitted to rigorously measure mandatory parameters for the determination of strain performance – i.e. growth rate and oil content. For that purpose, mini-photobioreactors run in parallel were used together with an exhaustive lipid class analysis. The quantitative productivity measurements indicated that the ten screened strains presented very different patterns in the conditions of PBR culture, firstly run in batch, and secondly in continuous mode. Indeed, with the applied setup, only four strains presented biomass productivities close to that previously measured for the reference strain 807/1 (between 74 and 307 mg L −1 day −1 of biomass for the tested strains). HC productivity obtained under continuous light (∼14 mg L −1 day −1 ) was close to that measured for the strain 807/1 (∼20 mg L −1 day −1 ), confirming B. braunii tested strains potential for biofuel application. The analysis of the lipid chemodiversity revealed moreover that this genus should be further investigated for its polar lipids, as it suggests potential pharmaceutical applications such as production of antitumorals or immunosuppressors. [ABSTRACT FROM AUTHOR]

Almost all oleaginous microorganisms are available for biodiesel production, and for the mechanism of oil accumulation, which is what makes a microbial approach economically competitive. This study investigated the potential that the yeast Candida lipolytica UCP0988, in an anamorphous state, has to produce simultaneously a bioemulsifier and to accumulate lipids using inexpensive and alternative substrates. Cultivation was carried out using waste soybean oil and corn steep liquor in accordance with 22 experimental designs with 1% inoculums (107 cells/mL). The bioemulsifier was produced in the cell-free metabolic liquid in the late exponential phase (96 h), at Assay 4 (corn steep liquor 5% and waste soybean oil 8%), with 6.704 UEA, IE24 of 96.66%, and showed an anionic profile. The emulsion formed consisted of compact small and stable droplets (size 0.2-5 μm), stable at all temperatures, at pH 2 and 4, and 2% salinity, and showed an ability to remove 93.74% of diesel oil from sand. The displacement oil (ODA) showed 45.34 cm2 of dispersion (central point of the factorial design). The biomass obtained from Assay 4 was able to accumulate lipids of 0.425 g/g biomass (corresponding to 42.5%), which consisted of Palmitic acid (28.4%), Stearic acid (7.7%), Oleic acid (42.8%), Linoleic acid (19.0%), and γ-Linolenic acid (2.1%). The results showed the ability of C. lipopytica to produce both bioemulsifier and biodiesel using the metabolic conversion of waste soybean oil and corn steep liquor, which are economic renewable sources. [ABSTRACT FROM AUTHOR]

This review includes works published in the general scientific literature during 2015 on the production of bioenergy and biofuel from waste residues generated during bioethanol and biodiesel production with a brief overview of current and emerging feedstocks. A section of this review summarizes literature on culturing algae for biofuels including bioreactors and open pond cultivation systems with the utilization of inorganic and organic sources of nutrients. New methods applicable to the mass culture of algae are highlighted. Algal cell harvesting and oil extraction techniques tested and developed for algae discussed alongwith policies and economics are also provided. [ABSTRACT FROM AUTHOR]

Co-hydroprocessing of petroleum fractions with residual lipids is a promising technology for hybrid fuels production. The aim of this study is the identification of an effective operating window for co-hydroprocessing of Heavy Atmospheric Gas Oil (HAGO) with Waste Cooking Oil (WCO) within the nominal operating limits of a refinery. In particular, two Liquid Hourly Space Velocities or LHSVs (0.66 and 1 h −1 ) and three hydrogen-to-oil or H 2 /Oil ratios (300, 400 and 500 L H 2 /L feed) were studied for a HAGO/WCO 90/10 V/V blended feedstock over a commercial hydrotreating NiMo/Al 2 O 3 catalyst. The two parameters were evaluated with respect to the attained diesel content and quality of the produced hybrid fuels. All experiments were performed at a constant pressure of 5.6 MPa and temperature of 350 °C. The results have shown that higher LHSV is preferable in terms of the hydrogen consumption affecting the conversion cost. As far as H 2 /Oil is concerned, high H 2 /Oil ratios are more effective, rendering higher conversion, diesel content and heteroatom removal. [ABSTRACT FROM AUTHOR]

Biological lipids derived from oleaginous microorganisms are promising precursors for renewable biofuel productions. Direct lipid extraction from wet cell-biomass is favored because it eliminates the need for costly dehydration. However, the development of a practical and scalable process for extracting lipids from wet cell-biomass is far from ready to be commercialized, instead, requiring intensive research and development to understand the lipid accessibility, mechanisms in mass transfer and establish robust lipid extraction approaches that are practical for industrial applications. This paper aims to present a critical review on lipid recovery in the context of biofuel productions with special attention to cell disruption and lipid mass transfer to support extraction from wet biomass. [ABSTRACT FROM AUTHOR]

High moisture content in wet algal biomass hinders effective performance of current lipid extraction methods. An improved aqueous extraction method combing thermal and enzymatic lysis was proposed and performed in algal slurry of Nannochloropsis oceanica (96.0% moisture) in this study. In general, cell-wall of N. oceanica was disrupted via thermal lysis and enzymatic lysis and lipid extraction was performed using aqueous surfactant solution. At the optimal conditions, high extraction efficiencies for both lipid (88.3%) and protein (62.4%) were obtained, which were significantly higher than those of traditional hexane extraction and other methods for wet algal biomass. Furthermore, an excessive extraction of polar lipid was found for wet biomass compared with dry biomass. The advantage of this method is to efficiently extract lipids from high moisture content algal biomass and avoid using organic solvent, indicating immense potential for commercial microalgae-based biofuel production. [ABSTRACT FROM AUTHOR]

High moisture content in wet algal biomass hinders effective performance of current lipid extraction methods. An improved aqueous extraction method combing thermal and enzymatic lysis was proposed and performed in algal slurry of Nannochloropsis oceanica (96.0% moisture) in this study. In general, cell-wall of N. oceanica was disrupted via thermal lysis and enzymatic lysis and lipid extraction was performed using aqueous surfactant solution. At the optimal conditions, high extraction efficiencies for both lipid (88.3%) and protein (62.4%) were obtained, which were significantly higher than those of traditional hexane extraction and other methods for wet algal biomass. Furthermore, an excessive extraction of polar lipid was found for wet biomass compared with dry biomass. The advantage of this method is to efficiently extract lipids from high moisture content algal biomass and avoid using organic solvent, indicating immense potential for commercial microalgae-based biofuel production. [ABSTRACT FROM AUTHOR]

• Methyl esterification targets lipids of coccolithophore. • Coccolithophore lipids were methyl-esterified at lower temperature than green alga. • Coccolithophore cell wall, composed of CaCO 3 , acted as a catalyst. • Effect of CaCO 3 on the methyl esterification by supercritical methanol was examined using green alga. • CaCO 3 is more effective than CaSO 4 -0.5H 2 O, which was previously considered effective. The methyl esterification of lipids employing supercritical methanol is an environmentally benign method since it does not produce alkaline wastewater, as is the case with conventional methods employing sodium hydroxide. Previous studies have shown that solid base catalysts are effective in decreasing reaction temperatures in the supercritical methanol methyl esterification. We focused on the coccolithophore Pleurochrysis carterae , which exhibits coccolith, i.e., CaCO 3 cell walls, and confirmed that the coccoliths acted as a catalyst in the methyl esterification of lipids in P. carterae employing supercritical methanol. To confirm the catalytic effect of the coccolith, the results of the supercritical methanol reaction of extracted lipids from P. carterae without coccolith were compared. The results showed that significant differences occurred, confirming that coccolith of P. carterae acts as a catalyst. To confirm the catalytic effect of CaCO 3 , the main component of coccolith, the green alga Chlorella vulgaris with cellulose cell walls was used to compare non-catalyst, addition of CaCO 3 and addition of CaSO 4 –0.5H 2 O, which is reported to be effective. The results revealed that the amount of the product obtained from the methyl esterification of fatty acids in C. vulgaris employing CaCO 3 was more significant than those obtained without any catalyst or with CaSO 4 –0.5H 2 O, indicating the effectiveness of CaCO 3 as a catalyst for methyl esterification by supercritical methanol. Coccolithophores, which exhibit CaCO 3 cell walls, are desirable raw materials for biofuels because they can function as catalysts. [ABSTRACT FROM AUTHOR]

Botryococcus terribilis is a peculiar species that directs a higher portion of the consumed CO 2 to metabolite biosynthesis. It results in a low growth rate associated with high oil productivity - compared to other species. In addition to its oils (mainly composed of lipids and hydrocarbons), this microalgae is also a promising source of proteins, carbohydrates, and pigments. The biosynthesis of these products depends on the cultivation conditions. Moreover, the extraction method applied has a direct influence on the quality of the products and their possible applications. Botryococcus terribilis metabolites can be used as fertilizers, biomaterials, pharmaceuticals, cosmetics, food supply, and in a range of biofuels (biodiesel, bioethanol, and biogas). However, biorefinery with this microalgae still needs to overcome economic and technical hurdles to reach a competitive market value. This work analyzed the evolution of the studies with the Botryococcus terribilis , approaching it main metabolites and relating it to the cultivation conditions, extraction methods, and the final products that can be obtained. For the first time, the studies with Botryococcus terribilis were summarized, creating a guide for further research on this microalgae by presenting the recommended conditions for its cultivation and extraction, its possible applications, the information missing in the literature, and the prospects for scale-up. • Approach the microalgae from metabolism to prospects for large-scale cultivation. • Summarize the conditions and results obtained with Botryococcus terribilis. • Botryococcus hydrocarbons are promising source of biofuels and biomaterials. • Botryococcus extracellular metabolites can be continuously extracted. • Recommendations and opportunities for further research with Botryococcus terribilis. [ABSTRACT FROM AUTHOR]

Taxonomy and phylogeny of twenty two microalgal isolates were examined using both universal and newly designed molecular primers. Among the isolates, Scenedesmus bijugus , Coelastrella sp., Auxenochlorella protothecoides , and Chlorella sp. were particularly promising in terms of producing lipids as measured by fatty acid methyl esters (FAME) analysis and significant concentration of carotenoids. A comparative experiment showed that S. bijugus and Chlorella sp. were the most promising candidates (L − 1 d − 1 , with biomass) 174.77 ± 6.75, 169.81 ± 5.22 mg, lipids 40.14 ± 3.31, 39.72 ± 3.89 mg, lutein 0.47, 0.36 mg, and astaxanthin 0.27, 0.18 mg respectively. The fatty acids produced by these microalgal isolates were mainly palmitic, stearic, oleic, linoleic, and linolenic acid. The freshwater microalgal isolate S. bijugus be the most suitable isolate for producing biodiesel and carotenoids, due to high productivity of biomass, lipids, metabolites, and its suitable fatty acid profile. [ABSTRACT FROM AUTHOR]

In this study, five Chlorella species ( Chlorella vulgaris, Chlorella minutissima, Chlorella pyrenoidosa, Chlorella sp.1 and Chlorella sp.2) were grown in various nutrient medium including BG-11, BBM, Fog's medium and MN medium for the evolution of biomass and lipid production potential. Among the tested medium, BG-11 was found most economical and efficient medium for all Chlorella species. To see the impact of organic carbon sources on lipid production potential, all microalgae species were also cultured in selected medium (BG-11) with different organic carbon sources like glucose, glycerol, sodium acetate, and sucrose under mixotrophic condition. The results showed that all Chlorella species performs better under mixotrophic condition, but Chlorella vulgaris achieved maximum lipid productivity (3.5 folds higher) in glycerol supplemented culture medium than control medium among all species. [ABSTRACT FROM AUTHOR]

Biofuel production from microalgae requires energy efficient processes for extracting and converting triacylglyceride lipids to fuel, compatible with coproduction of protein feeds and nutraceuticals. Wet solvent extraction involves mechanical cell rupture, lipid extraction via solvent contacting, physical phase separation, thermal solvent recovery, and transesterification. A detailed analysis of the effect of key process parameters on the parasitic energy demand of this process was performed. On a well-to-pump basis, between 16% and 320% of the resultant biodiesel energy was consumed depending solely on the process parameters. Highly positive energy balances can be achieved, but only if a correctly designed process is used. This requires processing concentrated biomass ( ca 25% w/w) with a high triacylglyceride content ( ca 30% w/w), and an efficient extraction process employing a non-polar solvent, low solvent-to-paste ratio, and efficient energy recovery. These requirements preclude many laboratory scale processes and polar co-solvents as viable options for large-scale biofuel production. [ABSTRACT FROM AUTHOR]

Currently microalgae are considered as an efficient biological producer of oil. Present study was conducted to explore the lipid yield percentage of three microalgal strains Chlorella sp., Oedogonium sp. and Spirogyra sp. Bligh and Dyer, Soxhlet, Folch and Microwave assisted extraction methods were employed for oil extraction. It was observed that Bligh and Dyer method with Chloroform-methanol (1:2, v/v) gave maximum extraction yield (15.46 ± 0.240%) for Chlorella sp. whereas Folch method with chloroform-methanol (2:1, v/v) gave more lipid yield as compared to Bligh and Dyer method i.e 5.53 ± 0.240% for Spirogyra sp., 13.67 ± 0.240% and 19.69 ± 0.667% for Oedogonium sp. and Chlorella sp. respectively. Soxhlet extraction resulted in less (14.5± 0.45) percentage yield as compared to Bligh and Dyer and Folch method (16.7± 0.24). Microwave assisted extraction with chloroform- methanol resulted in highest lipid yield (30%) with Chlorella sp. indicating that it contained the maximum lipid content among all the three species. [ABSTRACT FROM AUTHOR]

In the present investigation, the application of NMR spectroscopic techniques was extensively used with an objective to explore the biodiesel potential of biomass cultivated on a lab scale using strains of Chlorella vulgaris and Scenedesmus ecornis. The effect of variation in the composition of culturing medium on the neutral and polar lipids productivity, and fatty acid profile of solvent extracts of microalgae biomass was studied. Determination of unsaturated fatty acid composition (C18:N = 1-3, ω3 C20:5, ω3 C22:6), polyunsaturated fatty esters (PUFEs), saturated fatty acids (SFAs), unsaturated fatty acids (UFAs), free fatty acids (FFAs), and iodine value were achieved from a single H NMR spectral analysis. The results were validated by C NMR and GC-MS analyses. It was demonstrated that newly developed methods based on H and C NMR techniques are direct, rapid, and convenient for monitoring the microalgae cultivation process for enhancement of lipid productivity and their quality aspects in the solvent extracts of microalgal biomasses without any sample treatment and prior separation compared to other methods. The fatty acid composition of algae extracts was found to be similar to vegetable and fish oils, mostly rich in C16:0, C18:N (N = 0 to 3), and n-3 omega polyunsaturated fatty acids (PUFAs). The lipid content, particularly neutral lipids, as well as most of the quality parameters were found to be medium specific by both the strains. The newly developed methods based on NMR and ultrasonic procedure developed for efficient extraction of neutral lipids are cost economic and can be an effective aid for rapid screening of algae strains for modulation of lipid productivity with desired biodiesel quality and value-added products including fatty acid profile. [ABSTRACT FROM AUTHOR]

This study presents gravimetric enrichment of mixed culture to screen starch and lipid producing species separately in a sequencing batch reactor. In the enriched starch-producing mixed culture photobioreactor, the starch content at the end of steady state batch became 3.42 times the beginning of depletion. Whereas in the enriched lipid-producing photobioreactor, the lipid content at the end of steady state batch became 3 times the beginning of famine phase. The obtained results revealed that the gravimetric enrichment is a suitable screening method for specific production of storage compounds in none-sterile large-scaled condition. [ABSTRACT FROM AUTHOR]

This review includes works published in the general scientific literature during 2014 on the production of bioenergy and biofuel from waste residues generated during bioethanol and biodiesel production with a brief overview of current and emerging feedstocks. Another section of this review summarizes literature on culturing algae for biofuels including bioreactors and open pond cultivation systems with the utilization of inorganic and organic sources of nutrients. New methods applicable to the mass culture of algae are highlighted. Algal cell harvesting and oil extraction techniques tested and developed for algae are also discussed. [ABSTRACT FROM AUTHOR]

Sustainable mass production of algal biofuels requires a reduction in nutrient demand and efficient conversion into fuels of all biomass including lipid-extracted algal residues (LEA). This study evaluated methane production, nutrient recovery and recycling from untreated and enzymatically pretreated Nannochloropsis LEA using semi-continuous anaerobic digestion (AD). Additionally, this process was compared to methane generation from whole Nannochloropsis alga (WA) and thermally pretreated WA. The methane production from untreated LEA and WA reached up to 0.22 L and 0.24 L per gram of biomass volatile solids (VS), respectively, corresponding to only 36–38% of the theoretical potential. Additionally, observed VS reduction was only 40–50% confirming biomass recalcitrance to biodegradation. While enzymatic treatment hydrolyzed up to 65% of the LEA polysaccharides, the methane production increased by only 15%. Alternatively, WA thermal pretreatment at 150–170 °C enhanced methane production up to 40%. Overall, an integrated process of lipid conversion into biodiesel coupled with LEA conversion into methane generates nearly 40% more energy compared to methane production from WA, and about 100% more energy than from biodiesel alone. Additionally, the AD effluent contained up to 60–70% of the LEA phosphorus content, 30–50% of the nitrogen, sulfur, calcium and boron, 20% of the iron and cobalt, and 10% of manganese, zinc and copper, which can partially replace chemical fertilizers during algal cultivation. Consequently, supplementation of Nannochloropsis cultures with 5% AD effluent was optimal for a high algal growth rate. Therefore, coupling biodiesel and methane production provides significant energy advantages along with sustainability and economic benefits from nutrient recycling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Intrinsic interactions between lipid feedstocks and lipid-based biofuels. • Advancements in lipid-associated biofuel technology. • Properties and applicability of various lipid sources for biofuel production. • Biotechnology and progress in lipid production for advanced biofuels. The expanding use of fossil fuels has caused concern in terms of both energy security and environmental issues. Therefore, attempts have been made worldwide to promote the development of renewable energy sources, among which biofuel is especially attractive. Compared to other biofuels, lipid-derived biofuels have a higher energy density and better compatibility with existing infrastructure, and their performance can be readily improved by adjusting the chemical composition of lipid feedstocks. This review thus addresses the intrinsic interactions between lipid feedstocks and lipid-based biofuels, including biodiesel, and renewable equivalents to conventional gasoline, diesel, and jet fuel. Advancements in lipid-associated biofuel technology, as well as the properties and applicability of various lipid sources in terms of biofuel production, are also discussed. Furthermore, current progress in lipid production and profile optimization in the context of plant lipids, microbial lipids, and animal fats are presented to provide a wider context of lipid-based biofuel technology. [ABSTRACT FROM AUTHOR]

Aim of the present study was collection and identification of native algal species, optimization of their growth conditions and comparison of their oil content. From the collected 20 samples 3 different algal species were identified. The effect of growth media, temperature, pH level, light intensity and aeration on growth of Spirogyra sp. and Oedogonium sp. and Chlorella sp. was recorded. It was observed that both Oedogonium sp. and Chlorella sp. grow well in Blue green medium while Spirogyra sp. showed better growth in terms of fresh weight in Bold Basal medium. Algal growth optimum temperature was between 24-28 oC. It was also observed that neither very low nor very high pH is suitable for algal growth and at pH 7.5 algae were able to grow at maximum with fresh weights of 4.89±0.091 g and 4.79±0.021 g for Spirogyra sp. and Oedogonium sp. respectively. Artificial fluorescent light resulted in an increased growth of algae as compared to sunlight or when algae placed near window and exposed to indirect sunlight. The oil content of the three algal species is in order Chlorella sp > Oedogonium sp. Spirogyra sp. Hence, Chlorella sp. was found to have the highest lipid content with 15.46±0.240% yield for lipid content. [ABSTRACT FROM AUTHOR]

This study focuses on evaluating the effect of residual lipid co-hydroprocessing with a heavy petroleum fraction, towards the production of a hybrid diesel fuel of increased sustainability. Firstly, the effect of Waste Cooking Oil (WCO) co-hydroprocessing with Heavy Atmospheric Gas Oil (HAGO) at different relative ratios (100/0, 95/5, 90/10, 85/15, 80/20 and 70/30 v/v) was evaluated in terms of diesel quality. The experimental results showed explicitly that the addition of WCO did not limit any hydroprocessing reactions targeted. Particularly WCO integration led to a significant diesel content increase which reached 13% for the highest WCO content feedstock (30% v/v), while increasing hydrogen consumption. The study showed that co-hydroprocessing of residual lipids within a refinery can provide an effective and no-risk pathway for integrating residual liquid biomass in transportation fuels, without significant capital investments, while the addition of 5–10% v/v WCO in the hydroprocessing feedstock is considered optimal in terms of H 2 additional requirements (∼6.5%), product quality and WCO availability. [ABSTRACT FROM AUTHOR]

This study presents experimental measurements of the biochemical methane production for whole and lipid extracted Nannochloropsis salina . Results show whole microalgae produced 430 cm 3 -CH 4 g-volatile solids −1 (g-VS) ( σ = 60), 3 times more methane than was produced by the LEA, 140 cm 3 -CH 4 g-VS −1 ( σ = 30). Results illustrate current anaerobic modeling efforts in microalgae to biofuel assessments are not reflecting the impact of lipid removal. On a systems level, the overestimation of methane production is shown to positively skew the environmental impact of the microalgae to biofuels process. Discussion focuses on a comparison results to those of previous anaerobic digestion studies and quantifies the corresponding change in greenhouse gas emissions of the microalgae to biofuels process based on results from this study. [ABSTRACT FROM AUTHOR]

Biodiesel has received much attention in recent years. Due to significant lipid and carbohydrate production and the ability to grow using nonpotable water sources, microalgae are being scrutinized as a potential high-yield feedstock for biofuel production. For biodiesel production, selection of suitable strain of microalgae depends on various factors, such as lipid productivity, percentage of lipids, biomass productivity, CO2 tolerance, and nutrient requirements. In both natural and engineered systems, microalgae can be exposed to a variety of environmental conditions that have an effect on cellular composition and growth rate. Furthermore, the amount of carbon fixed in lipids and carbohydrates is highly influenced by nutrient availability and environmental factors. This article reviews the potential of microalgae for lipid production and effects of environmental factors (e.g., light, temperature, and pH) and nutrient availability (e.g., nitrogen, carbon, phosphorus, and trace metals). [ABSTRACT FROM AUTHOR]

This review includes works published in the general scientific literature during 2013 on the production of bioenergy and biofuel from waste residues generated from bioethanol and biodiesel production with a brief overview of current and emerging feedstocks. A later section of this review summarizes literature on culturing algae for biofuels including bioreactors and open pond cultivation systems with the utilization of inorganic and organic sources of nutrients. New methods applicable to the mass culture of algae are highlighted. Algal cell harvesting and oil extraction techniques tested and developed for algae are also discussed. [ABSTRACT FROM AUTHOR]

Ketchup is highly viscous and contains high concentrations of carbohydrates. These properties make waste ketchup more costly to treat prior to disposal. In this study ketchup was used to grow Ochromonas danica, a phagotrophic microalga that can produce and accumulate intracellular lipids using soluble or particulate organic substrates. Effects of the following factors on high-density O. danica fermentation were evaluated: nitrogen source, pH, temperature, agitation speed, aeration method, dissolved oxygen concentration, and nutrient feeding strategy. Under the optimized conditions the alga grew with a doubling time of about 10h. Cell yield and intracellular lipid yield from the consumed ketchup carbohydrate were 40% and 18%, respectively. The intracellular lipid content could be raised to 40%. The developed process may also be applied to effectively convert other organic wastes to algal lipids, for use as, e.g., biofuel feedstock. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sterol rich lipid was converted to a fuel in a single catalytic cracking step. [•] The cracking of sterol liberates hydrogen, resulting in a reduced olefin content. [•] Cracking over Pd/C gave a fuel with high ratio of linear alkanes & ∼10% aromatics. [•] The resulting hydrocarbon fuel could be blended up to 50% with ULSD. [Copyright &y& Elsevier]

This research assessed the efficacy of three harvesting methods on a strain of Dunaliella viridis. While there is strong potential to use lipids from microalgae as a feedstock for biofuels to replace petroleum-based fuel, at present microalgal harvesting for biofuel production is not yet economically feasible or energy efficient. pH-induced flocculation (by adjusting the pH of exponentially growing cells), indirect electrocoagulation (applying aluminum hydroxide coagulant to culture), and hollow fiber filtration (separating biomass from medium using tangential flow) were compared as potential harvesting mechanisms for small-scale (3-10 L) and large-scale (30-150 L) volumes of D. viridis. Both pH-induced flocculation and electrocoagulation yielded significant biomass recovery (>95 %), but both methods required removal of added chemicals and/or coagulant before the medium could be reused. In contrast, hollow fiber filtration did not require added chemicals or coagulant, and as another advantage, the filtrate was successfully reused as culture medium without apparent detrimental effects on cell size, cell shape, or cell production. When high salinity stress was imposed on the concentrate produced from the filtration method, total fatty acids (FAs) did not increase. However, total FAs did significantly increase after hollow fiber filtration (49 %) in comparison to FA content before filtration (36 %). This research indicates that hollow fiber filtration as a commercial harvesting mechanism offers attractive advantages as a harvesting mechanism for microalgae such as Dunaliella, relative to pH-induced flocculation and indirect electrocoagulation. [ABSTRACT FROM AUTHOR]

Abstract: Because some algae can be grown photoautotrophically, heterotrophically, and/or mixotrophically, they show promise for lipid production as biofuel feedstock with different conditions. In this study, we analyzed microalga Chlorella sorokiniana for biomass and lipid production under three culture modes. The best growth performance was obtained under mixotrophic conditions compared with photoautotrophic and heterotrophic conditions. With the addition of 4 g L−1 glucose, the specific growth rate (3.40 d−1) and maximum biomass dry weight (DW, 3.55 g L−1) in the mixotrophic culture were 1.8- and 2.4-fold of those in the heterotrophic culture, and 5.4- and 5.2-fold of those under the photoautotrophic culture. Most significantly, the biomass yield based on consumed glucose reached values of up to 0.82 g g−1, which was only 0.34 g g−1 in the corresponding heterotrophic condition. Moreover, the lipid content in mixotrophic algae also substantially increased. At a light intensity of 50 μmol m−2 s−1, a lipid content of 45% was achieved compared to only 13% in the heterotrophic culture. The PSII inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) had little effect on the maximum DW and lipid content in the heterotrophic culture, but caused a significant decline in the mixotrophic culture. Mixotrophic cultures supplied with air grew as well as cultures supplied with 1% CO2. Mixotrophy also changed the temperature profiles for growth, increasing the optimum from 25 °C to 37 °C. These results indicate that C. sorokiniana may be an ideal candidate for mixotrophic cultivation that offers great potential in the production of renewable biomass for bioenergy applications. [Copyright &y& Elsevier]

Regardless of current market conditions and availability of conventional petroleum sources, alternatives are needed to circumvent future economic and environmental impacts from continued exploration and harvesting of conventional hydrocarbons. Diatoms and green algae (microalgae) are eukaryotic photoautotrophs that can utilize inorganic carbon (e.g., CO) as a carbon source and sunlight as an energy source, and many microalgae can store carbon and energy in the form of neutral lipids. In addition to accumulating useful precursors for biofuels and chemical feed stocks, the use of autotrophic microorganisms can further contribute to reduced CO emissions through utilization of atmospheric CO. Because of the inherent connection between carbon, nitrogen, and phosphorus in biological systems, macronutrient deprivation has been proven to significantly enhance lipid accumulation in different diatom and algae species. However, much work is needed to understand the link between carbon, nitrogen, and phosphorus in controlling resource allocation at different levels of biological resolution (cellular versus ecological). An improved understanding of the relationship between the effects of N, P, and micronutrient availability on carbon resource allocation (cell growth versus lipid storage) in microalgae is needed in conjunction with life cycle analysis. This mini-review will briefly discuss the current literature on the use of nutrient deprivation and other conditions to control and optimize microalgal growth in the context of cell and lipid accumulation for scale-up processes. [ABSTRACT FROM AUTHOR]

Background Microalgae are a promising platform for producing neutral lipids, to be used in the application for biofuels or commodities in the feed and food industry. A very promising candidate is the oleaginous green microalga Scenedesmus obliquus, because it accumulates up to 45% w/w triacylglycerol (TAG) under nitrogen starvation. Under these conditions, starch is accumulated as well. Starch can amount up to 38% w/w under nitrogen starvation, which is a substantial part of the total carbon captured. When aiming for optimized TAG production, blocking the formation of starch could potentially increase carbon allocation towards TAG. In an attempt to increase TAG content, productivity and yield, starchless mutants of this high potential strain were generated using UV mutagenesis. Previous studies in Chlamydomonas reinhardtii have shown that blocking the starch synthesis yields higher TAG contents, although these TAG contents do not surpass those of oleaginous microalgae yet. So far no starchless mutants in oleaginous green microalgae have been isolated that result in higher TAG productivities. Results Five starchless mutants have been isolated successfully from over 3,500 mutants. The effect of the mutation on biomass and total fatty acid (TFA) and TAG productivity under nitrogenreplete and nitrogen-depleted conditions was studied. All five starchless mutants showed a decreased or completely absent starch content. In parallel, an increased TAG accumulation rate was observed for the starchless mutants and no substantial decrease in biomass productivity was perceived. The most promising mutant showed an increase in TFA productivity of 41% at 4 days after nitrogen depletion, reached a TAG content of 49.4% (% of dry weight) and had no substantial change in biomass productivity compared to the wild type. Conclusions The improved S. obliquus TAG production strains are the first starchless mutants in an oleaginous green microalga that show enhanced TAG content under photoautotrophic conditions. These results can pave the way towards a more feasible microalgae-driven TAG production platform. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thermal hydrolysis–pyrolysis was used to produce hydrocarbon from inedible lipids. [•] Feedstock fatty acid composition did not influence organic liquid product yield. [•] Organic liquid product had compounds in the gasoline and diesel boiling range. [•] The organic liquid product mostly met the CGSB specification for diesel fuel. [ABSTRACT FROM AUTHOR]

Highlights: [•] Algal biomass is a promising renewable energy source. [•] We review the potential of diatoms, an algal taxon, to become this energy source. [•] We suggest biological and technical ways to improve production and yield of diatoms. [•] Diatoms can replace fossil fuel using <5% of the USA land area. [Copyright &y& Elsevier]

The paper describes the genome sequence, gene annotation, and transcriptional profiling of the microalga Nannochloropsis gaditana B-31. The study identifies possible targets of genetic modification that could improve the yield of the strain for biodiesel production. The genome resource is available online at www.nannochloropsis.org with multiple tools for information retrieval.Nannochloropsis is rapidly emerging as a model organism for the study of biofuel production in microalgae. Here, we report a high-quality genomic assembly of Nannochloropsis gaditana, consisting of large contigs, up to 500 kbp long, and scaffolds that in most cases span the entire length of the chromosomes. We identified 10646 complete genes and characterized possible alternative transcripts. The annotation of the predicted genes and the analysis of cellular processes revealed traits relevant for the genetic improvement of this organism such as genes involved in DNA recombination, RNA silencing, and cell wall synthesis. We also analyzed the modification of the transcriptional profile in nitrogen deficiency—a condition known to stimulate lipid accumulation. While the content of lipids increased, we did not detect major changes in expression of the genes involved in their biosynthesis. At the same time, we observed a very significant down-regulation of mitochondrial gene expression, suggesting that part of the Acetyl-CoA and NAD(P)H, normally oxidized through the mitochondrial respiration, would be made available for fatty acids synthesis, increasing the flux through the lipid biosynthetic pathway. Finally, we released an information resource of the genomic data of N. gaditana, available online at www.nannochloropsis.org. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Environmental factors were proved to be helpful to lipid accumulation. [•] NaCl, Fe3+ and nitrogen starvation together made lipid content increase to 2.5 times. [•] Both high and low temperature could promote lipid accumulation. [•] UTEX 2341 was proved to be a potential species for high-quality biodiesel production. [ABSTRACT FROM AUTHOR]

Highlights: [•] Haematococcus pluvialis was cultivated in domestic secondary effluent. [•] The maximal biomass productivity of 27.8mgL−1 d−1 was achieved. [•] Nitrogen and phosphorus in the secondary effluent both were removed efficiently. [•] The maximal lipid accumulation rate of 12.0mgL−1 d−1 was obtained. [•] Haematococcus pluvialis outperformed most microalgal species in literatures. [ABSTRACT FROM AUTHOR]

Currently, very few studies address the relationship between diversity and biomass/lipid production in primary producer communities for biofuel production. Basic studies on the growth of microalgal communities, however, provide evidence of a positive relationship between diversity and biomass production. Recent studies have also shown that positive diversity-productivity relationships are related to an increase in the efficiency of light use by diverse microalgal communities. Here, we hypothesize that there is a relationship between diversity, light use, and microalgal lipid production in phytoplankton communities. Microalgae from all major freshwater algal groups were cultivated in treatments that differed in species richness and functional group richness. Polycultures with high functional group richness showed more efficient light use and higher algal lipid content with increasing species richness. There was a clear correlation between light use and lipid production in functionally diverse communities. Hence, a powerful and cost-effective way to improve biofuel production might be accomplished by incorporating diversity related, resource-use-dynamics into algal biomass production. [ABSTRACT FROM AUTHOR]

Piggery effluent is one of the most highly produced wastewaters throughout the world, containing high levels of inorganic nutrient species. In this study, a microalga Scenedesmus obliquus YSW-14 ( S. obliquus) was employed not only for nutrient removal from piggery wastewater effluent but also for lipid accumulation in the algal biomass as a feedstock for biofuel production. The piggery wastewater effluent was diluted up to fivefold with synthetic media to reduce the toxicity of (in)organic components, which resulted in improved microalgal growth, nutrient removal, and lipid productivity. Among the examined culture conditions, a 40% concentration of wastewater effluent was found to be most effective for microalga lipid productivity (). S. obliquus removed 155 mg total nitrogen and 4 mg total phosphate per gram of dried algae for growth at the same dilution condition. These results demonstrate the feasibility of using microalgae for advanced wastewater treatment and subsequent production of lipids as biofuel feedstock. [ABSTRACT FROM AUTHOR]

Abstract: This review aims to provide up-to-date knowledge on existing feedstocks for biofuels production (mainly biodiesel) from lipid-based biomasses. The 1st generation of lipid-based feedstocks was edible plant oils, whilst other alternative feedstocks were discovered and reported as the 2nd generation feedstocks. The 2nd generation feedstocks that are summarized in this work include non-edible oils, waste vegetable oil, animal fats, industrial wastes and by-products, lipid derived from insects and microorganisms. The general strong points of the 2nd generation feedstocks are that they are inexpensive, of high productivity and typically do not compete ethically or economically with food crops (edible oils). However, all 2nd generation feedstocks usually have a high level of moisture and free fatty acids that cause an extremely negative effect on conventional biodiesel production process. Thus, this article provides basic information on the processing techniques that are capable of handling 2nd generation feedstocks as well. [Copyright &y& Elsevier]

Highlights: [•] Dielectric spectroscopy (DES) was used to detect algal lipid accumulation. [•] DES could be automated for real-time industrial algal lipid monitoring. [•] A transmission line model of cell suspension permittivity was developed. [•] This initial model correctly predicts observed changes in dielectric properties. [Copyright &y& Elsevier]

The current situation due to the exhaustion of fossil fuels, increasing oil prices and environmental difficulties, urgent demand for alternative sources of energy, be an option promising the biodiesel: biofuel produced primarily from oils from oleaginous plants, the availability of which unfortunately, is incapable of replacing the petrodiesel market. The use of microalgae for biodiesel production is an advantageous alternative due to the high lipid content and ideal profile for obtaining biofuels they offer. In addition to this, other attributes are its high microalgae photosynthetic efficiency, which make them excellent sequestering of CO2, its ability to grow both in marine waters, sweet and salty waste, and its relatively high growth rate. However, microalgae culture systems currently have some limitations such as: insufficient information for scaling, difficulty maintaining monocultures, high operating costs for the production and harvesting of microalgae biomass, etc. Given these inconveniences, optimizing their culture systems is essential. The purpose of this paper is to design a research strategy that provides a critical overview of this alternative and bioenergetics, by analyzing the fundamentals of it. [ABSTRACT FROM AUTHOR]

The phenotypic and phylogenetic diversity of micro-algae capable of accumulating triacylglycerols provides a challenge for the accurate determination of biotechnological potential. High-yielding strains are needed to improve economic viability and their compositional information is required for optimizing biodiesel properties. To facilitate a high-throughput screening programme, a very rapid direct-derivatization procedure capable of extracting lyophilized material for GC analysis was compared with a scaled-down Folch-based method. This was carried out on ten micro-algal strains from 6 phyla where the more rapid direct-derivatization approach was found to provide a more reliable measure of yield. The modified Folch-based procedure was found to substantially underestimate oil yield in one Chlorella species ( P < 0.01). In terms of fatty acid composition however, the Folch procedure proved to be slightly better in recovering polyunsaturated fatty acids, in six out of the ten strains. Therefore, direct-derivatization is recommended for rapid determination of yields in screening approaches but can provide slightly less compositional accuracy than solvent-based extraction methods. [ABSTRACT FROM AUTHOR]

Phaeodactylum tricornutum is a marine diatom in the class Bacillariophyceae and is important ecologically and industrially with regards to ocean primary production and lipid accumulation for biofuel production, respectively. Triacylglyceride (TAG) accumulation has been reported in P. tricornutum under different nutrient stresses, and our results show that lipid accumulation can occur with nitrate or phosphate depletion. However, greater lipid accumulation was observed when both nutrients were depleted as observed using a Nile Red assay and fatty acid methyl ester (FAME) profiles. Nitrate depletion had a greater effect on lipid accumulation than phosphate depletion. Lipid accumulation in P. tricornutum was arrested upon resupplementation with the depleted nutrient. Cells depleted of nitrogen showed a distinct shift from a lipid accumulation mode to cellular growth post-resupplementation with nitrate, as observed through increased cell numbers and consumption of accumulated lipid. Phosphate depletion caused lipid accumulation that was arrested upon phosphate resupplementation. The cessation of lipid accumulation was followed by lipid consumption without an increase in cell numbers. Cells depleted in both nitrate and phosphate displayed cell growth upon the addition of both nitrate and phosphate and had the largest observed lipid consumption upon resupplementation. These results indicate that phosphate resupplementation can shut down lipid accumulation but does not cause cells to shift into cellular growth, unlike nitrate resupplementation. These data suggest that nutrient resupplementation will arrest lipid accumulation and that switching between cellular growth and lipid accumulation can be regulated upon the availability of nitrogen and phosphorus. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lipids in engineered cellulosic feedstocks can be source for biodiesel. • Hydrothermal pretreatment (170 °C, 20 min) was found to be optimal. • Enzymatic hydrolysis allows 79% glucose and 86% xylose recovery. • Pretreatment and enzymatic hydrolysis results in 2-fold increase in lipid. • Triglycerides and free fatty acids were observed in enzymatic residue and liquor. Lipids accumulated in the vegetative tissues of cellulosic feedstocks can be a potential raw material for biodiesel and bioethanol production. In this work, bagasse of genetically engineered sorghum was subjected to liquid hot-water pretreatment at 170, 180, and 190 °C for different reaction time. Under the optimal pretreatment condition (170 °C, 20 min), the residue was enriched in glucan (57.39 ± 2.63 % w/w) and xylan (13.38 ± 0.49 % w/w). The total lipid content of the pretreated residue was 6.81% w/w, similar to that observed in untreated bagasse (6.30% w/w). Pretreatment improved the enzymatic digestibility of bagasse, allowing a recovery of 79% w/w and 86% w/w of glucose and xylose, respectively. The pretreatment and enzymatic saccharification resulted in a 2-fold increase in total lipid in enzymatic residue compared to the original bagasse. Thus, pretreatment and enzymatic hydrolysis enabled high sugar recovery while concentrating triglycerides and free fatty acids in the residue. [ABSTRACT FROM AUTHOR]

There is a growing interest for the mixotrophic cultivation of microalgae using sustainable natural carbon sources. Chitin from shrimp waste was hydrolyzed using chitinase from Trichoderma asperellum and was exploited for the mixotrophic cultivation of microalgae. Chitin saccharification was optimized using Box-Behnken design to produce 50.41% (w/w) of reducing sugars using chitin, 0.83% (w/v), chitinase, 2.92 (v/v), temperature, 40 °C and time, 4.48 h. The biomass productivity of Tetradesmus obliquus and Aphanocapsa sp. was promoted to 39.1 and 40.57 mg L−1 day−1 in the presence of 0.5 g L−1 of N -acetylglucosamine oligomers (GlcNAc), which was estimated to be ∼1.9 and ∼2-folds higher than the autotrophic conditions, respectively. Modified Logistic kinetic model confirmed higher growth rates and shortened lag-time of the mixotrophic cultures. The lipid productivity of both microalgae species was >1.5-times higher than the autotrophic conditions. Nitrate removal from the culture medium was found to be an effective strategy to increase both lipid content and lipid productivity for T. obliquus , but this strategy was not effective for Aphanocapsa sp. Fatty acid analysis revealed an increase of saturated fatty acids under mixotrophic cultivation for both microalgae species. Additionally, several biodiesel evaluation parameters indicated superior characteristics for the mixotrophic culture compared to the autotrophic conditions. Accordingly, mixotrophic growth of microalgae using GlcNAc as a new, sustainable carbon and nitrogen source opens a new avenue for biofuel production with an effective waste conversion into valuable commodities. • Enzymatic production of reducing sugars from shrimp chitin was optimized to yield 50.41% (w/w). • Algal lipid productivity was enhanced >1.5 fold using chitin hydrolysate. • Nitrate removal enhanced lipid production of Tetradesmus obliquus. • Biodiesel from algal lipids obtained by mixotrophy had improved characteristics. [ABSTRACT FROM AUTHOR]

Microalgae have been considered as a promising biomass for biofuel production, but freshwater resource consumption during the scaled-up cultivation are still a challenge. Obtaining robust marine strains capable of producing triacylglycerols and high value-added metabolites are critical for overcoming the limitations of water resources and economical feasibility. In this study, a marine microalga with lipid and astaxanthin accumulation capability was isolated from Bohai Bay, China. The alga was named as Coelastrum sp. HA-1 based on its morphological and molecular identification. The major characteristics of HA-1 and the effects of nitrogen on its lipid and astaxanthin accumulations were investigated. Results indicated that the highest biomass, lipid and astaxanthin yields achieved were 50.9 g m-2 day-1, 18.0 g m-2 day-1 and 168.9 mg m-2 day-1, respectively, after cultivation for 24 days. The fatty acids of HA-1, identified in their majority as oleic acid (56.6%) and palmitic acid (25.9%), are desirable biofuel feedstocks. In addition, this alga can be harvested with simple sedimentation, achieving 98.2% removal efficiency after settling for 24 h. These results suggest that Coelastrum sp. HA-1 has several desirable key features that make it a potential candidate for biofuel production. [ABSTRACT FROM AUTHOR]