Effect of culture hydrodynamics on Arthrospira platensis production using a single-use photobioreactor system through a CFD supported approach.

Laboratory scale conventional single-use bioreactor was used to investigate the effect of different stirrer speeds on the Arthrospira platensis (Spirulina platensis) culture. Experiments were handled in two steps. First step was the selection of the stirring speeds, which was simulated via using CFD, and the second was the long term cultivation with the selected speed. During 10 days of batches as the first step, under identical culture conditions, stirrer speed of 230 rpm gave higher results, compared to 130 and 70 rpm, with respect to dry biomass weight, absorbance value (AB) and chlorophyll-a concentration. Volumetric productivity during the growth phase of the cultures were calculated as 0.39 ± 0.03, 0.28 ± 0.01, and 0.19 ± 0.02 g L-1 d-1, from the fast to the slower speeds. According to the results a 17 day batch was handled with 230 rpm in order to monitor the effects on the culture. The culture reached a volumetric productivity of 0.33 ± 0.04 g L-1 d-1. Statistical analysis showed the significance of the parameters related with the stirring speed.

Animal Cell Lines as Expression Platforms in Viral Vaccine Production: A Post Covid-19 Perspective.

Vaccines are considered the most effective tools for preventing diseases. In this sense, with the Covid-19 pandemic, the effects of which continue all over the world, humanity has once again remembered the importance of the vaccine. Also, with the various epidemic outbreaks that occurred previously, the development processes of effective vaccines against these viral pathogens have accelerated. By these efforts, many different new vaccine platforms have been approved for commercial use and have been introduced to the commercial landscape. In addition, innovations have been made in the production processes carried out with conventionally produced vaccine types to create a rapid response to prevent potential epidemics or pandemics. In this situation, various cell lines are being positioned at the center of the production processes of these new generation viral vaccines as expression platforms. Therefore, since the main goal is to produce a fast, safe, and effective vaccine to prevent the disease, in addition to existing expression systems, different cell lines that have not been used in vaccine production until now have been included in commercial production for the first time. In this review, first current viral vaccine types in clinical use today are described. Then, the reason for using cell lines, which are the expression platforms used in the production of these viral vaccines, and the general production processes of cell culture-based viral vaccines are mentioned. Also, selection parameters for animal cell lines as expression platforms in vaccine production are explained by considering bioprocess efficiency and current regulations. Finally, all different cell lines used in cell culture-based viral vaccine production and their properties are summarized, with an emphasis on the current and future status of cell cultures in industrial viral vaccine production.

The potential of microalgal sources as coating materials: A case study for the development of biocompatible surgical sutures.

Sutures are considered as surgical materials that form excellent surfaces to integrate the postoperative parts of the body. These materials present suitable platforms for potential bacterial penetrations. Therefore, coating these biomedical materials with biocompatible compounds is seen as a potential approach to improve their properties while avoiding adverse effects. The aim of this study was to evaluate Arthrospira platensis, Haematacoccus pluvialis, Chlorella minutissima, Botyrococcus braunii, and Nostoc muscorum as potential surgical suture coating materials. Their crude extracts were absorbed into two different sutures as poly glycolic (90%)-co-lactic acid (10%) (PGLA) and poly dioxanone (PDO); then, their cytotoxic effects and antibacterial activities were examined. Both N. muscorum-coated sutures (PGLA and PDO) and A. platensis-coated (PGLA and PDO) sutures did not induce any toxic effect on L929 mouse fibroblast cells (>70% cell viability). The highest antibacterial activity against Staphylococcus aureus was achieved with N. muscorum-coated PGLA and A. platensis-coated PGLA at 11.18 ± 0.54 mm and 9.52 ± 1.15 mm, respectively. These sutures were examined by mechanical analysis, and found suitable according to ISO 10993-5. In comparison with the commercial antibacterial agent (chlorohexidine), the results proved that N. muscorum extract can be considered as the most promising suture coating material for the human applications.

Influenza Vaccine: An Engineering Vision from Virological Importance to Production.

According to data from the World Health Organization (WHO) every year, millions of people are affected by flu. Flu is a disease caused by influenza viruses. For preventing this, seasonal influenza vaccinations are widely considered the most efficient way to protect against the negative effects of the flu. To date, there is no "one-size-fits-all" vaccine that can be effective all over the world to protect against all seasonal or pandemic influenza virus types. Because influenza virus transforms its genetic structure and it can emerges as immunogenically new (antigenic drift) which causes epidemics or new virus subtype (antigenic shift) which causes pandemics. As a result, annual revaccination or new subtype viral vaccine development is required. Currently, three types of vaccines (inactivated, live attenuated, and recombinant) are approved in different countries. These can be named "conventional influenza vaccines" and their production are based on eggs or cell culture. Although, there is good effort to develop new influenza vaccines for broader and longer period of time protection. In this sense these candidate vaccines are called "universal influenza vaccines". In this article, after we mentioned the short history of flu then virus morphology and infection, we explained the diseases caused by the influenza virus in humans. Afterward, we explained in detail the production methods of available influenza vaccines, types of bioreactors used in cell culture based production, conventional and new vaccine types, and development strategies for better vaccines.

Recent Progress in Microalgal Squalene Production and Its Cosmetic Application.

Squalene, [oxidized form squalane] is a terpenoid with biological activity that produced by animals and plants. In the human body, a significant excretion named as sebum includes squalene in 12 percent. This bioactive compound shows anti-inflammatory, detoxifying, moisturizing and antioxidant effects on the human body. In addition to having these properties, it is known that squalene production decreases as less sebum is produced with age. Because of that, the need for supplementation of squalene through products has arisen. As a result, squalene production has been drawn attention due to its many application possibilities by cosmetic, cosmeceutical and pharmaceutical fields. At this point, approximately 3,000 of sharks, the major and the most popular source of squalene must be killed to obtain 1 ton of squalene. These animals are on the verge of extinction. This situation has caused to focus on finding microalgae strains, which are sustainable producers of squalene as alternative to sharks. This review paper summarizes the recent progresses in the topic of squalene. For this purpose, it contains information on squalene producers, microalgal squalene production and cosmetic evaluation of squalene.

A study of the THP-1 cell line as the potential biologics production platform with the emphasis on serum-free media substitution for economic expediency.

Cell cultures are frequently preferred in the industrial production of high value-added biopharmaceuticals on a large scale. In the production of biopharmaceuticals, the selection of the appropriate cell line, the cell culture medium, and the culture conditions are very important. In medical products to be offered for human use, authorized institutions do not allow the use of serum which increases the culture yield, added to the culture. For this reason, the cell lines to be used must be adapted to the serum-free medium. In this study, first, the direct and gradual adaptation of the THP-1 cell line, which has a high potential for use in biopharmaceutical production, to a locally produced chemically defined serum-free medium was carried out. Then, a comparison of the production efficiency in the shake flasks with the commercially available two different serum-free media was performed. Finally, for the first time, THP-1 cells were produced in spinner flasks and stirring tank bioreactor to simulate the large scale within the scope of this work.

Exosomes: Large-scale production, isolation, drug loading efficiency, and biodistribution and uptake.

Exosomes are nanovesicles with different contents that play a role in various biological and pathological processes. It offers significant advantages over other delivery systems such as liposomes and polymeric nanoparticles. Although exosomes are expected to be effective therapeutic agents, their optimal use remains a challenge. The development of methods for large-scale production, isolation, and drug loading is necessary to improve their efficiency and therapeutic potential. In this review, after mentioning general properties and biological functions of the exosomes, details of their potential for use in the drug delivery system are presented. For this purpose, methodologies for the large-scale production of exosomes, exosome isolation, exosomal cargo loading, and exosome uptake by the recipient cell are reviewed. The current challenges and potential directions of this new area of drug delivery that has become popular recently are also investigated.

Design of melanogenesis regulatory peptides derived from phycocyanin of the microalgae Spirulina platensis.

Pigmentation issues are common conditions associated with excessive or insufficient production of melanin. Recently peptides are investigated to discover novel melanogenesis regulators as low molecular weight compounds to regulate skin pigmentation. In this study, an internal library of peptides obtained through in silico enzymatic digestion of phycocyanin from microalgae S. platensis was tested to apprehend their anti-melanogenic effects. Seven peptides were investigated for their inhibitory potential against mushroom and B16-F10 murine tyrosinase enzymes. According to the results, P5 (SPSWY) and P7 (AADQRGKDKCARDIGY) were effective in lowering the activity of mushroom and B16-F10 tyrosinases. P5 was the most potent (IC50 value, 12.1 µM) in mushroom which was followed by P2 (MAACLR, 86.9 µM). Although the peptides were particularly powerful in inhibiting monophenolase activity, only moderate inhibition was observed for diphenolase activity in mushroom tyrosinase assay. Apart from tyrosinase inhibition, P2 and P3 (RCLNGRL) were efficient DPPH radical scavengers at low concentrations (IC50 < 200 µM). In the mammalian assay system, P5 and P7 were noticeably effective to decrease tyrosinase enzyme activity with IC50 values of 48.9 and 34.2 µM, respectively. However, although P4 (RYVTYAVF) was a potent mushroom tyrosinase inhibitor, it increased melanin synthesis up to 3-fold in B16-F10 cells. The results indicate that C-terminal tyrosine residue is important for tyrosinase inhibition. This study shows, for the first time, that microalgae proteins can be regarded as sources for melanogenesis regulation.

Effect of Agitation and Aeration on Keratinase Production in Bioreactors Using Bioprocess Engineering Aspects.

Streptomyces sp. 2M21 was evaluated for keratinase production in bioreactors using chicken feathers. Firstly, optimization of bioengineering parameters (agitation and aeration rates) using Response Surface Methodology was carried out in 2 L bioreactors. Optimized conditions identified by the modified quadratic model were verified as 150 rpm and 1 vvm experimentally corresponding to 351 U/ml of keratinase activity. Moreover, scaling up sequentially to 20 L bioreactors was implemented using constant impeller tip speed and constant mass transfer coefficient as key scale-up parameters. The keratinase activity in 5, 10 and 20 L bioreactors showed similar results with the one of shake flasks (412 U/ml) and 2 L bioreactors (351 U/ml)with respect to the keratinase activity values of 336, 385 and 344 U/ml, respectively. The results suggest keratinase production by evaluating chicken feathers in commercial level. Furthermore, this study has potential to contribute industrial scale production of keratinase by Streptomyces sp. 2M21 using the proposed bioreactor conditions.

The effect of medium and light wavelength towards Stichococcus bacillaris fatty acid production and composition.

Introduction of novel species will highlight technical feasibility of microalgae-based biofuels for commercial applications. This paper reports the effect of culture medium and light wavelength on biomass and fatty acid production of S. bacillaris which holds some advantages as short life cycle, easy cultivation, high lipid content, diversity of fatty acids and stability under harsh environmental conditions. The results displayed that, soil extract (SE) greatly enhance growth rate of cultures. Maximum biomass and lipid productivity were achieved in TAP medium as 81 mg/L·day, 19.44 mg/L·day; respectively. Light wavelength didn't significantly change growth kinetics but played a critical role on chlorophyll-a accumulation. C14:0, C16:0 and C18:0 fatty acids were abundant which are suitable for biodiesel conversion. Interestingly, blue and red light increased longer chain fatty acids content. These results indicated that; S. bacillaris holds potential for further development of biodiesel production and feasibility of algal biodiesel for fundamental and applied sciences.

Preparation of electrospun polycaprolactone nanofiber mats loaded with microalgal extracts.

Sustainable, ecological, and biocompatible materials are emerging for the development of novel components for tissue engineering. Microalgae being one of the unique organisms on Earth to provide various novel compounds with certain bioactivities are also a good source for the development of novel tissue scaffold materials. In this study, electrospinning technique was utilized to fabricate nanofibers from polycaprolactone loaded with microalgal extracts obtained from Haematococcus pluvialis (vegetative and carotenoid producing form) and Chlorella vulgaris. The FTIR results showed that, blending microalgae with polycaprolactone give unique bands rooted from microalgae and polycaprolactone structure. The samples were not diversified from each other, however stable bands were observed. SEM analysis revealed a uniform fiber fabrication with an average diameter of 810 ± 55 nm independent from microalgal extracts. MTT assay was done on HUVEC cell lines and results showed that nanofiber mats helped cell proliferation with extended time. Biodegradation resulted with mineral accumulation on the surface of same samples however the fiber degradation was uniform. With slow but stable biodegradation characteristics, microalgal extract loaded nanofiber mats holds great potential to be novel tissue scaffold material.

Photobiological hydrogen production via immobilization: understanding the nature of the immobilization and investigation on various conventional photobioreactors.

Hydrogen photoproduction from microalgae has been an emerging topic for biofuel development. However, low yield for large-scale cultivations seems to be the main challenge. Immobilization seems to be an alternative method for sustainable hydrogen generation. In this study we examined the bead stability, bead diameter and immobilization method in accordance with photobioreactors (PBR). 2.1 mm diameter beads were selected for PBR experiments. CSTR, tubular and panel type PBRs give important results to develop suitable immobilization matrixes and techniques for mass production in scalable PBR systems. In conclusion, we suggest to develop techniques specific for the design and operation characteristic of the PBR for a yield efficient hydrogen generation.

Investigation of in vitro digestibility of dietary microalga Chlorella vulgaris and cyanobacterium Spirulina platensis as a nutritional supplement.

Microalgal proteins are promising sources for functional nutrition and a sustainable candidate for nutraceutical formulations. They also gain importance due to emerging focus on a healthy nutrition and increase in the number of chronic diseases. In this study, dried dietary species of microalga, Chlorella vulgaris, and cyanobacterium Spirulina platensis were hydrolyzed with pancreatin enzyme to obtain protein hydrolysates. The hydrolysis yield of biomass was 55.1 ± 0.1 and 64.8 ± 3.6% for C. vulgaris and S. platensis; respectively. Digestibility, as an indicator for dietary utilization, was also investigated. In vitro protein digestibility (IVPD) values depicted that cell wall structure due to the taxonomical differences affected both hydrolysis and digestibility yield of the crude biomass (p < 0.05). Epithelial cells (Vero) maintained their viability around 70%, even in relatively higher concentrations of hydrolysates in the culture. The protein hydrolysates showed no any antimicrobial activities. This study clearly shows that the conventional protein sources in nutraceutical formulations such as soy, whey, and fish proteins can be replaced by enzymatic hydrolysates of microalgae, which shows elevated digestibility values as a sustainable and reliable source.