Effect of nitrogen source in low-cost media on biomass and lipid productivity ofNannochloropsis salinafor large-scale biodiesel production

The effective transesterification process to produce fatty acid methyl esters (FAME) requires the use of low-cost, less corrosive, environmentally friendly and effective catalysts. Currently, worldwide biodiesel production revolves around the use of alkaline and acidic catalysts employed in heterogeneous and homogeneous phases. Homogeneous catalysts (soluble catalysts) for FAME production have been widespread for a while, but solid catalysts (heterogeneous catalysts) are a newer development for FAME production. The rate of reaction is much increased when homogeneous basic catalysts are used, but the main drawback is the cost of the process which arises due to the separation of catalysts from the reaction media after product formation. A promising field for catalytic biodiesel production is the use of heteropoly acids (HPAs) and polyoxometalate compounds. The flexibility of their structures and super acidic properties can be enhanced by incorporation of polyoxometalate anions into the complex proton acids. This pseudo liquid phase makes it possible for nearly all mobile protons to take part in the catalysis process. Carbonaceous materials which are obtained after sulfonation show promising catalytic activity towards the transesterification process. Another promising heterogeneous acid catalyst used for FAME production is vanadium phosphate. Furthermore, biocatalysts are receiving attention for large-scale FAME production in which lipase is the most common one used successfully This review critically describes the most important homogeneous and heterogeneous catalysts used in the current FAME production, with future directions for their use.

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Integrated bioprocess for conversion of gaseous substrates to liquids

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1516867113 ◽

2016 ◽

Vol 113 (14) ◽

pp. 3773-3778 ◽

Cited By ~ 78

Author(s):

Peng Hu ◽

Sagar Chakraborty ◽

Amit Kumar ◽

Benjamin Woolston ◽

Hongjuan Liu ◽

...

Keyword(s):

Acetic Acid ◽

Synthesis Gas ◽

Large Scale ◽

Low Cost ◽

Cost Effective ◽

Integrated System ◽

Biodiesel Production ◽

Liquid Fuels ◽

Acid Product ◽

The Individual

In the quest for inexpensive feedstocks for the cost-effective production of liquid fuels, we have examined gaseous substrates that could be made available at low cost and sufficiently large scale for industrial fuel production. Here we introduce a new bioconversion scheme that effectively converts syngas, generated from gasification of coal, natural gas, or biomass, into lipids that can be used for biodiesel production. We present an integrated conversion method comprising a two-stage system. In the first stage, an anaerobic bioreactor converts mixtures of gases of CO2 and CO or H2 to acetic acid, using the anaerobic acetogen Moorella thermoacetica. The acetic acid product is fed as a substrate to a second bioreactor, where it is converted aerobically into lipids by an engineered oleaginous yeast, Yarrowia lipolytica. We first describe the process carried out in each reactor and then present an integrated system that produces microbial oil, using synthesis gas as input. The integrated continuous bench-scale reactor system produced 18 g/L of C16-C18 triacylglycerides directly from synthesis gas, with an overall productivity of 0.19 g⋅L−1⋅h−1 and a lipid content of 36%. Although suboptimal relative to the performance of the individual reactor components, the presented integrated system demonstrates the feasibility of substantial net fixation of carbon dioxide and conversion of gaseous feedstocks to lipids for biodiesel production. The system can be further optimized to approach the performance of its individual units so that it can be used for the economical conversion of waste gases from steel mills to valuable liquid fuels for transportation.

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Assessment of microalgal ACCase and rbcl gene expression as a function of nutrient and metal stress

10.51415/10321/3110 ◽

2017 ◽

Author(s):

◽

Poonam Singh

Keyword(s):

Large Scale ◽

Scale Up ◽

Biomass Productivity ◽

Photosynthetic Performance ◽

Lipid Productivity ◽

Biodiesel Production ◽

Rbcl Gene ◽

Limited Condition ◽

Bg11 Medium ◽

Microalgal Biodiesel

Microalgae are considered to be a potential feedstock for biodiesel production. However, the main concern with regard to the large scale microalgal biodiesel production process is its competence and economic viability. The commercial realization of microalgal biodiesel production requires substantial impetus towards development of efficient strategies to improve lipid yields upstream. Nitrogen (N) and phosphorus (P) stress during cultivation are the widely used lipid accumulation strategies for microalgae. However, these individual nutrient stress strategies are associated with compromised biomass productivity which hampers overall lipid productivity. Lipid enhancement strategies based on light, temperature and CO2 are associated with technological barriers for scale up and incur additional cost. Thus, the main aim of this study was to develop an integrated, easily applicable and scalable lipid enhancement strategy based on nutrients and metals such as N, P, iron (Fe), magnesium (Mg), calcium (Ca) and EDTA stress for selected indigenous microalgal strains. The effect of metal concentrations individually and in combination on microalgal lipids and biomass production is a scarcely exploited area. In this study, a novel approach involving individual as well as combined metals and EDTA stress under N and P limited conditions for lipid enhancement in microalgae was investigated. Microalgal growth physiology, photosynthetic performance, biochemical composition (lipid, carbohydrate and protein) and expression of selected key genes involved in photosynthesis (rbcL) and fatty acid biosynthesis (accD) were studied both under selected individual and combined stress conditions. Out of seven microalgal isolates obtained during the initial isolation and screening process, two strains were selected for lipid enhancement study based on their growth rates, biomass yields, lipid content and lipid productivities. The strains were later identified as Acutodesmus obliquus and Chlorella sorokiniana based on both morphological characteristics and phylogenetical analysis. The selected strains were thereafter subjected to different cultivation conditions involving varying metal, EDTA and nutrient stress conditions. A significant increase in lipid productivity was observed when the concentrations of Fe, Mg and EDTA were increased and Ca was decreased to degree in the N and P stress BG11 medium. For A. obliquus, a highest lipid productivity of 80.23 mgL-1d-1 was achieved with the developed strategy under limited N (750 mg L-1) condition which was 2.18 fold higher than BG11 medium and 1.89 fold higher than N limited condition alone. Similarly, for C. sorokiniana, highest lipid productivity of 77.03 mgL-1d-1 was achieved with the developed strategy under limited N (500 mgL-1) and P (10 mgL-1) which was 2.67 fold higher than BG11 medium and 2.35 fold higher than N and P limited condition alone. For both the microalgal strains, Fe was the most significant trace metal affecting their lipid productivity. These above observations were further confirmed through photosynthetic performance analysis and gene expression studies. At mid log phase, 6.38 and 5.15 fold increases in the expression levels of rbcL gene were observed under combined stress (OCMS+OE) as compared to the control (BG11) condition in A. obliquus and C. sorokiniana respectively. This also resulted in an increased expression level of accD gene involved in lipid biosynthesis to 10.25 fold and 9.79 fold in A. obliquus and C. sorokiniana respectively at late log phase. The results from expression studies of rbcL and accD genes were in compliance with biomass yields, photosynthetic performance, protein yield and lipid productivities for both the strains under different cultivating conditions. The universal applicability of the above strategy was confirmed by applying it to five other microalgae strains isolated in this study which resulted in considerable increase in their overall lipid productivity under optimized conditions. Attempts were made to scale up the lab scale study to open circular pond (3000L) cultivation for A. obliquus. Results showed a 2.08 fold increase in lipid productivity under optimized conditions compared to the control, which emphasizes the scalability of the developed strategy even under uncontrolled conditions. In conclusion, the developed combined metal and EDTA stress strategy not only assisted in alleviating the biomass productivity but also enhanced the lipid accumulation which resulted in overall increased lipid productivity under N and P limited condition. Furthermore, the improved carbohydrate and protein productivities observed with the developed lipid enhancement strategy make it suitable for biorefinery approach with multiple products. An improvement in lipid profile and high biodiesel conversion were also observed with this universally applicable and scalable lipid enhancement strategy confirming their potential applicability during large scale cultivation for biodiesel production.

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Operation Regimes: A Comparison Based on Nannochloropsis oceanica Biomass and Lipid Productivity

Energies ◽

10.3390/en14061542 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1542

Author(s):

Inês Guerra ◽

Hugo Pereira ◽

Margarida Costa ◽

Joana T. Silva ◽

Tamára Santos ◽

...

Keyword(s):

Large Scale ◽

Continuous Cultivation ◽

Fold Increase ◽

Continuous Operation ◽

Lipid Productivity ◽

Biodiesel Production ◽

Nannochloropsis Oceanica ◽

Operation Regime ◽

Significant Research ◽

Tubular Photobioreactors

Microalgae are currently considered to be a promising feedstock for biodiesel production. However, significant research efforts are crucial to improve the current biomass and lipid productivities under real outdoor production conditions. In this context, batch, continuous and semi-continuous operation regimes were compared during the Spring/Summer seasons in 2.6 m3 tubular photobioreactors to select the most suitable one for the production of the oleaginous microalga Nannochloropsis oceanica. Results obtained revealed that N. oceanica grown using the semi-continuous and continuous operation regimes enabled a 1.5-fold increase in biomass volumetric productivity compared to that cultivated in batch. The lipid productivity was 1.7-fold higher under semi-continuous cultivation than that under a batch operation regime. On the other hand, the semi-continuous and continuous operation regimes spent nearly the double amount of water compared to that of the batch regime. Interestingly, the biochemical profile of produced biomass using the different operation regimes was not affected regarding the contents of proteins, lipids and fatty acids. Overall, these results show that the semi-continuous operation regime is more suitable for the outdoor production of N. oceanica, significantly improving the biomass and lipid productivities at large-scale, which is a crucial factor for biodiesel production.

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Optimization cultivation of Chlamydomonas reinhardtii in a tubular photobioreactor (2000 Liter) for biomass and green bioenergy (biodiesel) production

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha48311803 ◽

2020 ◽

Vol 48 (3) ◽

pp. 1439-1457

Author(s):

Hanaa H. ABD EL BAKY ◽

Gamal S. EL BAROTY

Keyword(s):

Fatty Acids ◽

Chlamydomonas Reinhardtii ◽

Lipid Content ◽

Large Scale ◽

Saturated Fatty Acids ◽

Economic Feasibility ◽

Lipid Productivity ◽

Biodiesel Production ◽

Tubular Photobioreactor ◽

High Lipid

The biodiesel can be produced from diverse microalgae lipids as alternative and renewable fuel. Thus, the aim of this study was to optimize the Chlamydomonas reinhardtii promising species as biodiesel feedstock for large-scale cultivation in Egypt. To understand some of the triggers required for the metabolic pathway switch to lipid accumulation, the effect of carbon sources and the three elements availability (N, P, S) in C. reinhardtii growth medium was determined. A local microalgae C. reinhardtii was cultured in modified Sueoka medium containing various concentrations of CO2 and bicarbonate (NaHCO3) (in 2-liter flasks) as a carbon source. The optimal source in term biomass, high lipid productivity (10.3 mgL-1d-1) and a higher lipid content (22.76%) were obtained in 6% CO2 culture. Then, the availability of N, P, S (various concentrations of N, P and S) nutrients elements was added to 6% CO2 culture, for produce a highest lipid content and lipid productivity. As expected, under low availability N-1.78 mM; P-0.14mM and S-0.10 mM mediums, C. reinhardtii showed a high accumulation lipid content. Therefore, to improve the economic feasibility of microalgae biofuels production, its concentrations were selected to combine (N+P+S) in order to cultivation of C. reinhardtii in a multi-tubular photobioreactor (400 liter) to produce high lipid contents. Under limited condition, the biomass dry weight, biomass productivity, lipid content and lipid productivity were found to be 3.11 (gL-1), 0.15±0.012 (g-1L-1d-1), 22.76% (w/w %) and 1.9± 0.35 (mg-1L-1d-1), respectively. The extracted lipid was found to have physical and chemical properties similar that plant oils using for biodiesel production. The FAME profiling of prepared biodiesel shows the presence of considerable amount of 36.97% saturated fatty acids (palmitic acid and stearic acid, together) with 27.33% unsaturated (oleic acid and linoleic acid) fatty acids. The FAME had a low iodine value and high CN, which meet with the appropriate of biodiesel standards (EN 14214 and ASTM D6751). Thus, C. reinhardtii appears to be more feasible for high quality biodiesel production.

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Efficient Production of Lactic Acid from Distillers Grains Hydrolysates by Rhizopus oryzae CICC41411

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.873.689 ◽

2013 ◽

Vol 873 ◽

pp. 689-696

Author(s):

Hai Wei Ren ◽

Jin Ping Li ◽

Yi Zhang ◽

Zhi Zhong Li

Keyword(s):

Lactic Acid ◽

Nitrogen Source ◽

Large Scale ◽

Rhizopus Oryzae ◽

Ph Value ◽

Low Cost ◽

Distillers Grains ◽

Utilization Rate ◽

Efficient Production ◽

Fermentation Time

Lignocellulosic biomass-derived sugars is considered to be an economically attractive carbohydrate feedstock for large-scale fermentation of bulk chemicals such as lactic acid (LA). The aim of this study was to investigate the possibility of LA production from distillers grains hydrolysates (DGHs) by the Rhizopus oryzae CICC41411 and to optimize the biological conversion of reducing sugar into LA to evaluate the culture conditions. The effects of factors such as nitrogen source, inoculations size, CaCO3 addition, pH value and fermentation time on the lactic acid concentration (LAC) and the reducing sugars utilization rate (RSUR) were researched. The results show that ammonium chloride is the most favorable nitrogen source for LA production by Rhizopus. Oryzae CICC41411, the optimal fermentation conditions are inoculation size of 2.5% seed culture, CaCO3 addition of 80 g·L-1, fermentation time of 96 h and culture pH of 6.0. This study provides an encouraging means of producing LA from lignocellulosic resource such as the low-cost distillers grains.

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Metabolome profiles of the alphaproteobacterial methanotroph Methylocystis sp. Rockwell in response to carbon and nitrogen source

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa219 ◽

2020 ◽

Author(s):

Marina Lazic ◽

Scott Sugden ◽

Dominic Sauvageau ◽

Lisa Y Stein

Keyword(s):

Carbon Source ◽

Nitrogen Source ◽

Metabolic Regulation ◽

Large Scale ◽

Metabolic Response ◽

Low Cost ◽

Critical Role ◽

Value Added ◽

Nitrogen Sources ◽

Carbon And Nitrogen

Abstract Methanotrophs use methane as a sole carbon source and thus play a critical role in its global consumption. Intensified interest in methanotrophs for their low-cost production of value-added products and large-scale industrialization has led to investigations of strain-to-strain variation in parameters for growth optimization and metabolic regulation. In this study, Methylocystis sp. Rockwell was grown with methane or methanol as a carbon source and ammonium or nitrate as a nitrogen source. The intracellular metabolomes and production of polyhydroxybutyrate, a bioplastic precursor, were compared among treatments to determine how the different combinations of carbon and nitrogen sources affected metabolite production. The methane-ammonium condition resulted in the highest growth, followed by the methane-nitrate, methanol-nitrate, and methanol-ammonium conditions. Overall, the methane-ammonium and methane-nitrate conditions directed metabolism toward energy-conserving pathways, while methanol-ammonium and methanol-nitrate directed the metabolic response toward starvation pathways. Polyhydroxybutyrate was produced at greater abundances in methanol-grown cells, independent of the nitrogen source. Together, the results revealed how Methylocystis sp. Rockwell altered its metabolism with different combinations of carbon and nitrogen source, with implications for production of industrially relevant metabolites.

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An Assessment of a Low-Cost Wastewater Disposal System after Twenty-Five Years of Operation

Water Science & Technology ◽

10.2166/wst.1987.0249 ◽

1987 ◽

Vol 19 (5-6) ◽

pp. 701-710 ◽

Cited By ~ 3

Author(s):

B. L. Reidy ◽

G. W. Samson

Keyword(s):

Large Scale ◽

Low Cost ◽

Wastewater Disposal ◽

Industrial Base ◽

Industrial Wastewaters ◽

The Past ◽

Gasification Process ◽

Appropriate Treatment ◽

Environmentally Safe ◽

Coal Resource

A low-cost wastewater disposal system was commissioned in 1959 to treat domestic and industrial wastewaters generated in the Latrobe River valley in the province of Gippsland, within the State of Victoria, Australia (Figure 1). The Latrobe Valley is the centre for large-scale generation of electricity and for the production of pulp and paper. In addition other industries have utilized the brown coal resource of the region e.g. gasification process and char production. Consequently, industrial wastewaters have been dominant in the disposal system for the past twenty-five years. The mixed industrial-domestic wastewaters were to be transported some eighty kilometres to be treated and disposed of by irrigation to land. Several important lessons have been learnt during twenty-five years of operating this system. Firstly the composition of the mixed waste stream has varied significantly with the passage of time and the development of the industrial base in the Valley, so that what was appropriate treatment in 1959 is not necessarily acceptable in 1985. Secondly the magnitude of adverse environmental impacts engendered by this low-cost disposal procedure was not imagined when the proposal was implemented. As a consequence, clean-up procedures which could remedy the adverse effects of twenty-five years of impact are likely to be costly. The question then may be asked - when the total costs including rehabilitation are considered, is there really a low-cost solution for environmentally safe disposal of complex wastewater streams?

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Rapid, large-scale species discovery in hyperdiverse taxa using 1D MinION sequencing

BMC Biology ◽

10.1186/s12915-019-0706-9 ◽

2019 ◽

Vol 17 (1) ◽

Cited By ~ 17

Author(s):

Amrita Srivathsan ◽

Emily Hartop ◽

Jayanthi Puniamoorthy ◽

Wan Ting Lee ◽

Sujatha Narayanan Kutty ◽

...

Keyword(s):

Dna Sequences ◽

Large Scale ◽

Low Cost ◽

Small Body ◽

Small Subset ◽

Similar Species ◽

Large Species ◽

Morphological Examination ◽

Species Discovery ◽

Short Period

Abstract Background More than 80% of all animal species remain unknown to science. Most of these species live in the tropics and belong to animal taxa that combine small body size with high specimen abundance and large species richness. For such clades, using morphology for species discovery is slow because large numbers of specimens must be sorted based on detailed microscopic investigations. Fortunately, species discovery could be greatly accelerated if DNA sequences could be used for sorting specimens to species. Morphological verification of such “molecular operational taxonomic units” (mOTUs) could then be based on dissection of a small subset of specimens. However, this approach requires cost-effective and low-tech DNA barcoding techniques because well-equipped, well-funded molecular laboratories are not readily available in many biodiverse countries. Results We here document how MinION sequencing can be used for large-scale species discovery in a specimen- and species-rich taxon like the hyperdiverse fly family Phoridae (Diptera). We sequenced 7059 specimens collected in a single Malaise trap in Kibale National Park, Uganda, over the short period of 8 weeks. We discovered > 650 species which exceeds the number of phorid species currently described for the entire Afrotropical region. The barcodes were obtained using an improved low-cost MinION pipeline that increased the barcoding capacity sevenfold from 500 to 3500 barcodes per flowcell. This was achieved by adopting 1D sequencing, resequencing weak amplicons on a used flowcell, and improving demultiplexing. Comparison with Illumina data revealed that the MinION barcodes were very accurate (99.99% accuracy, 0.46% Ns) and thus yielded very similar species units (match ratio 0.991). Morphological examination of 100 mOTUs also confirmed good congruence with morphology (93% of mOTUs; > 99% of specimens) and revealed that 90% of the putative species belong to the neglected, megadiverse genus Megaselia. We demonstrate for one Megaselia species how the molecular data can guide the description of a new species (Megaselia sepsioides sp. nov.). Conclusions We document that one field site in Africa can be home to an estimated 1000 species of phorids and speculate that the Afrotropical diversity could exceed 200,000 species. We furthermore conclude that low-cost MinION sequencers are very suitable for reliable, rapid, and large-scale species discovery in hyperdiverse taxa. MinION sequencing could quickly reveal the extent of the unknown diversity and is especially suitable for biodiverse countries with limited access to capital-intensive sequencing facilities.

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