A PDF presentation on "Microalgae Production and Their Use in Animal Feeds".
Digital library
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Microalgae have been studied for decades, but a new wave of research has recently begun as part of the search for renewable and sustainable energy sources. For economic optimization, microalgal biomass is being considered as a whole (main products and co-products) in an overall ‘biorefinery’ concept. Applications of microalgae cover a broad spectrum, including the food and (livestock) feed industries, bioenergy, cosmetics, healthcare and environmental restoration or protection. In the field of biotechnology, the access to genomic data is playing a growing role. As the cost of sequencing strategies has fallen, studies of gene function at the transcript, protein and biosynthesis pathway levels have multiplied. Notably, sequencing and mass spectrometry technologies are used to delineate the pathways of lipid synthesis, which will be valuable for the future application of microalgae in the biotechnology and biofuel industries. Another field making an applied use of genomics is the ‘cell factory’ approach, which uses the cell to manufacture (express) natural or recombinant proteins for diverse purposes. In this chapter, we present a vision of the potential future of genomics in the biotechnology of microalgae from several points of view.
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Microalgae contribute significantly to the global carbon cycle through photosynthesis. Given their ability to efficiently convert solar energy and atmospheric carbon dioxide into chemical compounds, such as carbohydrates, and generate oxygen during the process, microalgae represent an excellent and feasible carbohydrate bioresource. Microalgae-based biofuels are technically viable and, delineate a green and innovative field of opportunity for bioenergy exploitation. Microalgal polysaccharides are one of the most versatile groups for biotechnological applications and its content can be increased by manipulating cultivation conditions. Microalgal carbohydrates can be used to produce a variety of biofuels, including bioethanol, biobutanol, biomethane, and biohydrogen. This review provides an overview of microalgal carbohydrates, focusing on their use as feedstock for biofuel production, highlighting the carbohydrate metabolism and approaches for their enhancement. Moreover, biofuels produced from microalgal carbohydrate are showed, in addition to a new bibliometric study of current literature on microalgal carbohydrates and their use.
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The purpose of this chapter is to provide an overview of the main sys- tems of microalgae production with highlights of biofuel production. The large-scale production systems (raceway ponds, horizontal tubular photobioreac- tors, and heterotrophic bioreactors) and small-scale photobioreactors (vertical and flat-plate photobioreactors) will be presented and discussed with a special emphasis on the main factors affecting its efficiency, biomass productivities reported in the literature, scaling-up, costs of construction and operation, and commercial appli- cations. Besides this, the recent developments in microalgae cultivation systems will be reviewed in their main aspects. Finally, the criteria for selecting an appropriate bioreactor for microalgae cultivation will be presented, as well as the pros and cons of each system will be discussed in this chapter.
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Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Fatty acid methyl ester (FAME) profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN), iodine value (IV), cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study) and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA) ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary) and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA) contents. Application of a polyunsaturated fatty acid (PUFA) weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.
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Microalgal photosynthesis is efficient enough to fix C02 in both atmosphere and industrially discharged gases, and is a possible future alternative for C02 reduction. This paper describes physiological responses of microalgal cells to extremely high C02 concentrations, capability of microalgal cells to fix C02 at both indoor and outdoor culture experiments, and efforts to establish a culture collection of marine microalgae. Recent researches indicate that microalgae are likely to playa key role in worldwide issues of the coming century.
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This edited book, is a collection of 25 chapters describing the recent advancements in the application of microbial technology in the food and pharmacology sector. The main focus of this book is application of microbes, food preservation techniques utilizing microbes, probiotics, seaweeds, algae, enzymatic abatement of urethane in fermentation of beverages, bioethanol production, pesticides, probiotic biosurfactants, drought tolerance, synthesis of application of oncolytic viruses in cancer treatment, microbe based metallic nanoparticles, agro chemicals, endophytes, metabolites, antibiotics etc. This book highlighted the significant aspects of the vast subject area of microbial biotechnology and their potential applications in food and pharmacology with various topics from eminent experts around the World. This book would serve as an excellent reference book for researchers and students in the Food Science, Food Biotechnology, Microbiology and Pharmaceutical fields.
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High salinity is an effective measure to preserve kelp, but salted kelp can still deteriorate after long-term preservation. In order to clarify the key conditions and microbial behavior of salted kelp preservation, 10% (S10), 20% (S20), and 30% (S30) salt concentrations were evaluated at 25 ◦C (T25) and 4 ◦C (T4). After 30 days storage, these salted kelps showed different states including rot (T25S10), softening (T25S20), and undamaged (other samples). By detecting polysaccharide lyase activity and performing high-throughput sequencing of the prokaryotic 16S rRNA sequence and metagenome, we found that deteriorated kelps (T25S10 and T25S20) had significantly higher alginate lyase activity and bacterial relative abundance than other undamaged samples. Dyella, Saccharophagus, Halomonas, Aromatoleum, Ulvibacter, Rhodopirellula, and Microbulbifer were annotated with genes encoding endonuclease-type alginate lyases, while Bacillus and Thiobacillus were annotated as the exonuclease type. Additionally, no alginate lyase activity was detected in undamaged kelps, whose dominant microorganisms were halophilic archaea without alginate lyase-encoding genes. These results indicated that room-temperature storage may promote salted kelp deterioration due to the secretion of bacterial alginate lyase, while ultra-high-salinity and low-temperature storage can inhibit bacterial alginate lyase and promote the growth of halophilic archaea without alginate lyase, thus achieving the preservation of salted kelp.
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Competition between reef-building corals and benthic algae is of key importance for reef dynamics. These interactions occur on many spatial scales, ranging from chemical to regional. Using microprobes, 16S rDNA pyrosequencing and underwater surveys, we examined the interactions between the reef-building coral Montastraea annularis and four types of benthic algae. The macroalgae Dictyota bartayresiana and Halimeda opuntia, as well as a mixed consortium of turf algae, caused hypoxia on the adjacent coral tissue. Turf algae were also associated with major shifts in the bacterial communities at the interaction zones, including more pathogens and virulence genes. In contrast to turf algae, interactions with crustose coralline algae (CCA) and M. annularis did not appear to be antagonistic at any scale. These zones were not hypoxic, the microbes were not pathogen-like and the abundance of coral–CCA interactions was positively correlated with per cent coral cover. We propose a model in which fleshy algae (i.e. some species of turf and fleshy macroalgae) alter benthic competition dynamics by stimulating bacterial respiration and promoting invasion of virulent bacteria on corals. This gives fleshy algae a competitive advantage over corals when human activities, such as overfishing and eutrophication, remove controls on algal abundance. Together, these results demonstrate the intricate connections and mechanisms that structure coral reefs.
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The microbiological conversion of marine plant biomass was studied with stabilized kelp-degrading methane-producing enrichment cultures. Mannitol and alginate are used concurrently. Ethanol is produced shortly after feeding kelp and subsides rapidly. Dissolved hydrogen ranged from 5 nM to 1.2 uM. The appearance of ethanol correlates with increased hydrogen levels which is expected if interspecies hydrogen transfer functions to maintain low concentrations of the more reduced fermentation products. An improved method was developed for measurement of volatile fatty acids in sea water medium based on gas chromatography of the phenyl ester derivatives. Acetate and propionate were found in the greatest concentrations with formate, butyrate and isobutyrate in lower concentrations. The pool sizes will be used with turnover rate constants to determine total flux of each intermediate. A strain of Methanococcus mazei has been isolated that degrades acetate to methane. Also, a highly enriched culture of a previously unreported acetate-degrading methanogen was obtained. New strains of hydrogen and formate-utilizing methanogens were isolated. Mannitol and alginate degrading strains were isolated that resemble Cytophaga sp.
Formate dehydrogenase from Methanobacterium,,formicicum was purified 71-fold and initially characterized. The isolated enzyme contains a cofactor not previously reported in methanogens.
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