Algal Alginate in Biotechnology: Biosynthesis and Applications

Algae are recognized as the main producer of commercial alginate. Alginate produced using algae is located in the walls and intracellular regions of their cells. Its properties vary depending on the species, growing and harvesting seasons, and extraction methods. Alginate has attracted the attention of several industries, thanks to its unique properties such as its biodegradability, biocompatibility, renewability and lack of toxicity features. For example, it is considered a good encapsulation agent due to the transparent nature of the alginate matrices. Also, this biopolymer is recognized as a functional food in the food industry. It can be tolerated easily in human body and has the ability to reduce the risk of chronic diseases. Besides, it is used as an abrasive agent, antioxidant, and thickening and stabilizing agents in cosmetic and pharmaceutic industries. Generally, it is used in emulsion systems and wound dressing patches. Furthermore, this polysaccharide has the potential to be used in green nanotechnologies as a drug delivery vehicle via cell microencapsulation. Moreover, it is suitable to adopt as a coagulant due to its wide range of flocculation dose and high shear stability. In this chapter, the mentioned usage areas of algal alginate are explained in more detail

Trends in a natural product fucoxanthin

Fucoxanthin is a xanthophyll pigment which occurs in marine brown seaweeds (macroalgae), diatoms and several microalgae species. It forms with chlorophyll a-c and several proteins, a major fucoxanthin-chlorophyll a/c complex, which transfers light energy to the photosynthesis center and plays a major role in light harvesting. Recent studies have reported that fucoxanthin has many physiological functions and biological effects, such as anti-obesity, antidiabetic, anti-inflammatory, anticancer and cardiovascular system protection. Therefore, this pigment is highly preferred for the prevention and treatment of various chronic diseases. In addition, potential applications of high value fucoxanthin can be found in cosmetic, food and feed industries. In this review paper, the historical development, characteristic properties and possible sources of fucoxanthin are extensively described. The potential biological activities of fucoxanthin are also discussed. Finally, brief overview of common applications and market analysis of commercial fucoxanthin are also reported

Biochemobrionic: A novel functional bioactive and biomimetic material for bioengineering applications

From bioengineering perspective, integration of biological/organic compounds into the chemobrionic structures hold great promise for obtaining functional materials. The present study aimed to development of bioactive and biomimetic material by the incorporation of Arthrospira platensis microalgae into chemobrionics. The developed material, which will be called biochemobrionic, was constructed by the controlled injection of microalgaecontaining magnesium/calcium solution into silicate/phosphate solution. Incorporation of microalgal biomass and extract was confirmed by several characterization analysis. Furthermore, it was proven that incorporation of A. platensis extract improved the mechanical strength of the chemobrionics. Finally, cytotoxicity, biodegradability, and antioxidant activity assays were performed to explore the potential of extract-incorporated biochemobrionics as bioactive materials. Results showed that chemobrionic and biochemobrionic materials did not show remarkable cytotoxicity and integration of microalgal extract exhibited antioxidant activity at considerable levels. According to the findings, incorporation of microalgal product into chemobrionics may expand the scope of these structures and open new routes for potential application areas.This study was a part of Cost Action CA17120 and the authors would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK) with the project number 120M111 for the financial support. Authors also would like to thank Animal Cell Engineering and Bioprocess Laboratory of Ege University Bioengineering department for their valuable contribution to share animal cell culture lines and laboratory infrastructure for cytotoxicity tests.Scientific and Technological Research Council of Turkey (TUBITAK) [120M111

Evaluation of scale-up methodologies and computational fluid dynamics simulation for fucoxanthin production in airlift photobioareactor

Deniz, Irem/0000-0002-1171-8259; Imamoglu, Esra/0000-0001-8759-7388; Demirel, Zeliha/0000-0003-3675-7315WOS: 000539793500001Researches about commercial-scale production of fucoxanthin are increasing day by day due to the much interest of its broad beneficial health effects. the aim of this study was to investigate the scale-up methodologies in airlift photobioreactor and to simulate fluid flow using computational fluid dynamics (CFD) for fucoxanthin production fromPhaeodactylum tricornutummicroalgae. During the transition process from 1-L cultivation bottle to the 2-L airlift photobioreactor, the constant mixing time, the constant volumetric oxygen transfer coefficient, and the constant volumetric power consumption rate were evaluated as scale-up methodologies under laboratory conditions. Maximum fucoxanthin yield was found as 1.01 +/- 0.07 mg g(-1)using scale-up strategy based on constant volumetric power consumption rate. After that, CFD simulation was performed in order to examine flow characteristics, mixing efficiency, hydrodynamics, and gas holdup for selected operation conditions. It was observed that mixing efficiency was low because the draft tube configuration prevented the circulation of fluid and caused a heterogenic culture medium inside the reactor. It is possible to overcome this bottleneck by developing the effective draft tube.Turkiye Bilimsel ve Teknolojik Arastirma KurumuTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115M014]Turkiye Bilimsel ve Teknolojik Arastirma Kurumu, Grant/Award Number: 115M01

Evaluation of different scale-up strategies for Haematococcus pluvialis cultivation in airlift photobioreactors

Large scale algal biomass production can be very challenging due to the potential issues of sustainability, environmental ethics, and economic concerns. A strategic approach to the transition from the laboratory to the industrial scale allows the prediction of process characteristics, design and analysis of large scale systems, and reduction of extra costs. In this study, a scale-up procedure that considered different approaches was carried out by selecting the Haematococcus pluvialis as a model organism. Three scale-up parameters (constant mixing time (t(m)), volumetric power consumption rate (P/V), and oxygen mass transfer coefficient (k(L)a)) were tested for biomass production in a 2-L airlift photobioreactor and they were compared with those obtained from a 1-L aerated cultivation bottle. Among three strategies, the maximum cell concentration, 4.60 +/- 0.20x10(5) cells/mL, was obtained in a constant volumetric power consumption rate experiment. Also, total carotenoid amount showed similar changes with the cell concentration and reached the maximum concentration of 2.02 +/- 0.11 mg/L under constant P/V experiment. However, the cultivation bottle presented the highest biomass amount of 0.62 g/L and specific growth rate of 0.38 day(-1) of all of the photobioreactors. This result might be attributed to the low aeration rates or improper configuration of the system, which created a non-homogenous culture medium and led to ineffective mass transfer.This study was funded by the Scientific and Technological Research Council of Turkey (TUBITAK) under grant number [115M014] . Acknowledgements: This study was a part of Cost action ES1408 and the authors would like to thank the Scientific and Technolog- ical Research Council of Turkey (TUBITAK) (project number 115M014) for the financial support.Scientific and Technological Research Council of Turkey (TUBITAK) [115M014

Computational fluid dynamics modelling of stirred tank photobioreactor for Haematococcus pluvialis production: Hydrodynamics and mixing conditions

Deniz, Irem/0000-0002-1171-8259; Imamoglu, Esra/0000-0001-8759-7388WOS: 000572122100023Agitated photobioreactors (PBR) have been widespread for the cultivation of microalgae because of their advantages in mixing and mass transfer conditions. However, it is difficult to investigate the behaviors of cultivation broth flow with experimental procedures in these PBRs. Computational Fluid Dynamics (CFD) is a common method that has been used to simulate the performance of fluid containing systems in order to investigate the fluid flow, reduce the design cost and improve the efficiency. the objective of this study was to evaluate hydrodynamics and mixing conditions of stirred tank PBR for Haematococcus pluvialis production experimentally and numerically. the cells were first cultivated in a stirred tank PBR containing Rushton turbine impeller and the cell growth was examined during 10 days. At the end of cultivation, the cell concentration was reached the value of 3.1 +/- 0.1 x 10(5) cells mL(-1) with the total carotenoid content of 2.47 +/- 0.01 mg L-1. Then, the hydrodynamic analyses were conducted to evaluate the average velocity magnitude, turbulence properties and dead zone inside the PBR. the simulation results obtained from realizable k-epsilon turbulence model showed that the uniformity index of average velocity was found as 0.86. This result showed that the fluid flow showed similar behavior in the most parts of PBR except around the impellers. the velocity contours supported that the mixing conditions were supplied efficiently, however the vortex formation was observed around the impellers in spite of the baffles. in addition, the turbulence kinetic energy having a vital influence on mixing characteristics was found between the values of 1.0 x 10(-2) and 3.0 x 10(-2) m(2) s(-2) and the lowest values were observed between two impellers due to extent of mixing. Obtained results could be used to re-design PBR configurations considering the impeller type, the distance between impellers and cultivation conditions.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115M014]This study was a part of Cost action ES1408 and the authors would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK) with the project number of 115M014 for the financial support

Transition from start-up to scale-up for fucoxanthin production in flat plate photobioreactor

Deniz, Irem/0000-0002-1171-8259; Demirel, Zeliha/0000-0003-3675-7315; Imamoglu, Esra/0000-0001-8759-7388WOS: 000469393600002Fucoxanthin is one of the most important carotenoids and is found in diatoms such as Phaeodactylum tricornutum. the aim of this study was to evaluate the use of both the constant volumetric power consumption rate as scale-up strategy and the constant light energy per unit volume for transition from 1000-mL bottle to 2-L and 7-L flat plate photobioreactors for fucoxanthin production in P. tricornutum, considering whether an increase in the fucoxanthin yield could be achieved. the cell concentration and fucoxanthin content were enhanced with increasing the cultivation volume. It was found that the fucoxanthin yield increased 2.3 times in 2-L photobioreactor and 2.6 times in 7-L photobioreactor in comparison to the value of 1.05mgg(-1) dry weight in the cultivation bottle. Consequently, fucoxanthin production was successfully step-wise scaled-up from 1000-mL bottle to 7-L photobioreactor using both constant volumetric power consumption rate and the constant light energy per unit volume under laboratory conditions.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115M014]This study was a part of Cost action ES1408 and this study was financially supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with the project number of 115M014

A novel subcritical fucoxanthin extraction with a biorefinery approach

Eco-friendly, cost efficient and effective extraction methods have become significant for the industries applying zero waste principles. The two main objectives of this study were; to examine fucoxanthin extraction from wet Phaeodactylum tricornutum using subcritical fluid extraction and to characterize the residual biomass in order to determine the potential application areas. The highest fucoxanthin yield of 0.69 ± 0.05 mg/g wet cell weight was achieved using methanol with solvent-to-solid ratio of 200:1 at 120 rpm, 20 MPa pressure and at 35 °C for 60 min by subcritical extraction. Microscopy images showed that most of the cells were disrupted and intracellular components were effectively released. Based on the results of energy dispersive spectroscopy, biomass contained a mixture of organic molecules including mainly carbon (57–72%), oxygen (26–41%), magnesium (0.6–1.4%) and silica (0.4–1%) (wt%). These results make the residual biomass a potential candidate for various areas such as bioenergy, material sciences and sensor technologies