Lutein Production Research Articles

Pilot-scale cultivation of Chlorella sorokiniana FZU60 with a mixotrophy/photoautotrophy two-stage strategy for efficient lutein production

Chlorella sorokiniana FZU60, a lutein-enriching microalga, was cultivated in 50 L column photobioreactor to evaluate its potential for lutein production. Initial cell concentration, phosphate concentration and aeration rate were optimized, and results showed that optimal conditions of these three parameters were 0.10 g/L, 0.06 g/L and 0.02 vvm (2.5% CO2), respectively. In addition, a novel two-stage strategy was successfully developed, in which algae were firstly cultivated under fed-batch mixotrophic condition to achieve high biomass concentration, and then shifted to photoautotrophic condition for enhancing lutein accumulation. Moreover, dissolved oxygen was found to be an efficient indicator of acetate depletion in fed-batch stage. The obtained lutein content, production and productivity reached 9.51 mg/g, 33.55 mg/L and 4.67 mg/L/d, respectively, which were greater than those reported in other pilot-scale studies. This proposed strategy provided a cost-effective approach for high-efficient microalgae-based lutein production at pilot-scale, indicating great potential for commercial production.

Gamma irradiation of trilamellate packaged yellow corn ( Zea mays ) kernels enhances lutein content and shelf life

Yellow corn kernels were subjected to gamma (γ) irradiation (1.0–10.0 kGy), post packaging in polypropylene/polyethylene terephthalate/aluminium foil trilamellate. These packaged-irradiated corn grits were stored under ambient conditions (23 ± 2°C, 80% R.H.) and their shelf lives were ascertained chiefly w.r.t. lutein and aflatoxin contents. Among all samples investigated, 3 kGy-irradiated samples exhibited a unique combination of maximum carotenogenesis (lutein content: 422 ± 2.30 µg/100 g [d.b.] corn grits, on day 120) and minimum aflatoxin content (1.35 ± 0.10 µg/kg [d.b.] corn kernels, on day 120) during storage, causing minimum alterations to their sensory, physicochemical, phytochemical, and nutritional characteristics. Thus, packaged-cum-3 kGy-irradiated yellow corn kernels with a lead of 30 days in shelf life vis-à-vis their non-irradiated counterparts were considered to be the “best shelf stable” (shelf life: 120 days) sample set and γ-irradiation in combination with flexible packaging was established to be a new preservation technology for this horticultural produce. Practical applications Gamma (γ) irradiation is a well-known food preservation technology. Although there is published literature on the effects of the application of this technology on yellow corn kernels; enhancement of the content of its biotherapeutic molecule, lutein has not been reported. This study reports for the first time on increased carotenogenesis, that is, enhanced production of lutein (a member of the family of carotenoid pigments) in corn kernels consequent to γ-irradiation, besides increasing shelf lives of the irradiated kernels. The data presented in this study would be certainly useful for producers and consumers alike and offers a new advantage of γ-irradiation to industrial/commercial food irradiators who can commercialize the utilization of irradiated corn kernels as enhanced sources of its major bioactive compound, lutein.

Sustainable lipid and lutein production from Chlorella mixotrophic fermentation by food waste hydrolysate

Bioconversion of food waste into value-added products is a promising way to tackle the global food waste management problem. In this study, a novel valorisation strategy for bioenergy and lutein production via microalgal fermentation was investigated. Significant amount of glucose was recovered from enzymatic hydrolysis of food waste. The resultant hydrolysate was then utilised as culture medium in mixotrophic cultivation of Chlorella sp. to obtain high levels of lipid and lutein, whose accumulation patterns were consistent with molecular analyses. The resultant algal lipid derived from microalgal biomass using food hydrolysate was at high quality in terms of biodiesel properties. Further, in semi-continuous fermentation, the average algal biomass was 6.1 g L−1 with 2.5 g L−1 lipid and 38.5 mg L−1 lutein using hydrolysate with an initial glucose concentration of 10 g L−1. Meanwhile, the resultant algal biomass was 6.9 g L−1 with 1.8 g L−1 lipid and 63.0 mg L−1 lutein using hydrolysate with an initial glucose concentration of 20 g L−1, which suggests food waste hydrolysate could trigger algal products preferences. The experimental results of this study suggested the potential of microalgae as a platform for bioconversion of food waste into high-value products, especially sustainable bioenergy.

Enhanced biomass and lutein production by mixotrophic cultivation of Scenedesmus sp. using crude glycerol in an airlift photobioreactor

This study presents the mixotrophic cultivation of Scenedesmus sp. using crude glycerol (CG) obtained from lab scale biodiesel unit in an internal loop airlift photo-bioreactor (ALR) for enhanced biomass and lutein production. Prior to reactor studies, shake flask experiments were designed using Taguchi orthogonal array method to evaluate the influence of CG concentration, nitrogen to phosphorus ratio (N/P), and inhibitors concentration (methanol and KOH). Experimental run carried out with 5 g/l CG, 20:1 N/P ratio, 0.5 % methanol concentration, and 7.5 mg/l KOH produced a maximum biomass and lutein productivity of 310.18 mg/(l d) and 2.25 mg/(l d) respectively. During the mixotrophic cultivation of Scenedesmus sp. in an ALR, the step-wise addition of CG during the growth phase improved the productivity. The CG concentration of 6 g/l showed highest biomass and lutein productivity of 768 mg/(l d) and 3.59 mg/(l d), respectively. Monod and Logistic models were employed to fit the growth data. This study illustrated that the fed-batch strategy and mixotrophic cultivation offer higher biomass and lutein production.

Functional Identification of Two Types of Carotene Hydroxylases from the Green Alga Dunaliella bardawil Rich in Lutein.

The salt-tolerant unicellular alga Dunaliella bardawil FACHB-847 can accumulate large amounts of lutein, but the underlying cause of massive accumulation of lutein is still unknown. In this study, genes encoding two types of carotene hydroxylases, i.e., β-carotene hydroxylase (DbBCH) and cytochrome P450 carotenoid hydroxylase (DbCYP97s; DbCYP97A, DbCYP97B, and DbCYP97C), were cloned from D. bardawil. Their substrate specificities and enzyme activities were tested through functional complementation assays in Escherichia coli. It was showed that DbBCH could catalyze the hydroxylation of the β-rings of both β- and α-carotene, and displayed a low level of ε-hydroxylase. Unlike CYP97A from higher plants, DbCYP97A could not hydroxylate β-carotene. DbCYP97A and DbCYP97C showed high hydroxylase activity toward the β-ring and ε-ring of α-carotene, respectively. DbCYP97B displayed minor activity toward the β-ring of α-carotene. The high accumulation of lutein in D. bardawil may be due to the multiple pathways for lutein biosynthesis generated from α-carotene with zeinoxanthin or α-cryptoxanthin as intermediates by DbBCH and DbCYP97s. Taken together, this study provides insights for understanding the underlying reason for high production of lutein in the halophilic green alga D. bardawil FACHB-847.

Enhancing Biomass and Lutein Production From Scenedesmus almeriensis: Effect of Carbon Dioxide Concentration and Culture Medium Reuse.

The main purpose of this study is to investigate the effects of operative parameters and bioprocess strategies on the photo-autotrophic cultivation of the microalgae Scenedesmus almeriensis for lutein production. S. almeriensis was cultivated in a vertical bubble column photobioreactor (VBC-PBR) in batch mode and the bioactive compounds were extracted by accelerated solvent extraction with ethanol at 67°C and 10 MPa. The cultivation with a volume fraction of CO2 in the range 0–3.0%v/v showed that the highest biomass and lutein concentrations – 3.7 g/L and 5.71 mg/g, respectively – were measured at the highest CO2 concentration and using fresh growth medium. Recycling the cultivation medium from harvested microalgae resulted in decreased biomass and lutein content. The nutrient chemical composition analysis showed the highest consumption rates for nitrogen and phosphorus, with values higher than 80%, while sulfate and chloride were less consumed.

A comprehensive study on the effect of light quality imparted by light-emitting diodes (LEDs) on the physiological and biochemical properties of the microalgal consortia of Chlorella variabilis and Scenedesmus obliquus cultivated in dairy wastewater.

The effect of light wavelengths on the physiological, biochemical and lutein content of the microalgal consortia Chlorella variabilis and Scenedesmus obliquus was evaluated using different light sources. Among different light treatments, cool-white fluorescent light produced the highest biomass of 673 mg L-1 with a specific growth rate of 0.75 day-1 followed by blue (500 mg L-1; 0.73 day-1). The chlorophyll content was enhanced under blue light (10.7 mg L-1) followed by cool fluorescent light (9.3 mg L-1), whereas the lutein productivity was enhanced under cool fluorescent light (7.22 mg g-1). Protein content of the microalgal consortia was enhanced under all light treatments with the highest protein accumulation under cool-white fluorescent light (~56% of dry mass) closely followed by amber light (52% of dry mass), whereas the carbohydrate content was higher under amber light (~35% of dry mass). The results revealed that the consortia could grow well on diluted dairy wastewater thereby reducing the cost of algal production when compared with the use of inorganic media and a two-phase culture process utilizing cool fluorescent and amber light could be employed for maximizing algal biomass and nutrient composition with enhanced lutein production. The study also emphasizes on the economic efficiency of LED lights in terms of biomass produced based on the modest electricity consumed and the importance of using amber light for cultivating microalgae for its nutrient content which has seldom been studied.

Plant Origin, but Not Phylogeny, Drive Species Ecophysiological Response to Projected Climate.

Knowledge of the relationship between environmental conditions and species traits is an important prerequisite for understanding determinants of community composition and predicting species response to novel climatic conditions. Despite increasing number of studies on this topic, our knowledge on importance of genetic differentiation, plasticity and their interactions along larger sets of species is still limited especially for traits related to plant ecophysiology. We studied variation in traits related to growth, leaf chemistry, contents of photosynthetic pigments and activity of antioxidative enzymes, stomata morphology and photosynthetic activity across eight Impatiens species growing along altitudinal gradients in Himalayas cultivated in three different temperature regimes and explored effects of among species phylogenetic relationships on the results. Original and target climatic conditions determine trait values in our system. The traits are either highly plastic (e.g., APX, CAT, plant size, neoxanthin, β-carotene, chlorophyll a/b, DEPSC) or are highly differentiated among populations (stomata density, lutein production). Many traits show strong among population differentiation in degree of plasticity and direction in response to environmental changes. Most traits indicate that the species will profit from the expected warming. This suggests that different processes determine the values of the different traits and separating the importance of genetic differentiation and plasticity is crucial for our ability to predict species response to future climate changes. The results also indicate that evolution of the traits is not phylogenetically constrained but including phylogenetic information into the analysis may improve our understanding of the trait-environment relationships as was apparent from the analysis of SLA.

Co-production of lutein and fatty acid in microalga Chlamydomonas sp. JSC4 in response to different temperatures with gene expression profiles

Temperature has been regarded as an important factor for microalgal growth and the accumulation of lutein and fatty acid. In this study, the lutein and fatty acid producing microalga Chlamydomonas sp. JSC4 was cultivated at various temperatures (20, 25, 30, 35, and 40 °C). Maximum biomass productivity (1271 mg/L/d) and lutein productivity (3.27 mg/L/d) were achieved at 35 °C, whereas the highest lutein content (3.82 mg/g) was obtained at 20 °C. Similarly, maximum total fatty acid (TFA) productivity (177.31 mg/L/d) was obtained at 35 °C, yet TFA content (202.56 mg/g) was highest at 20 °C with increased unsaturated fatty acid proportion. It was observed that carotenoid, fatty acid, and protein contents increased, but carbohydrate content decreased at low temperature, which could be due to the modulation of metabolic flux from carbohydrate to carotenoid, fatty acid and protein. Inspection of gene expression profile showed that the lutein biosynthesis genes (psy, pds, and lut1) and fatty acid biosynthesis genes (bccp and bc) were upregulated at 20 °C when nitrate was replete and at the beginning of nitrate depletion. This study will help to develop temperature manipulation strategy and provide molecular basis of genetic engineering for improvement of the co-production of lutein and fatty acid in strain JSC4.

Lutein and biodiesel sequential production from microalga using an environmentally friendly approach

The use of microalgae as a raw material to extract pigments and biodiesel is an economical and environmental challenge due to the costs and toxicity of the chemical used, as well as the time and energy consumed in the production chain. Thus, the objective of this work was to develop an environmentally friendly sequential process to obtain lutein and biodiesel from Choricystis minor var. minor microalga. To overcome these challenges, the wet biomass of this microalga was dried in the sun, and lutein was obtained in an optimized extraction using methanolic solution containing potassium hydroxide, followed by the extraction of fatty acids and conversion into biodiesel using methanolic solution with phosphoric acid. The optimum conditions for lutein extraction were 0.3 mL of methanolic solution with 8% potassium hydroxide, at 60 °C for 1 hour. Then, the residual biomass was used to produce biodiesel by acid catalysis, with addition of 0.8 mL of methanolic solution containing 10% phosphoric acid at 100 °C for 1 hour. This approach obtained 1 kg of lutein and 10.83 kg of biodiesel from 75.75 kg of dry biomass of microalga. From the economical point of view, biodiesel is a less valuable coproduct of the lutein production chain.

Induction of β, ε-carotene-3, 3′-diol (lutein) production in green algae Chlorella salina with airlift photobioreactor: interaction of different aeration and light-related strategies

The impact and interaction of light irradiance strength (light intensities), lighting cycle (photoperiod), and aeration rate on biomass concentration and lutein production efficacy of the microalga Chlorella salina in a closed laboratory-scale airlift photobioreactor were investigated via the response surface method. Among the factors assessed, light intensity and aeration rate had significant influence on cell concentration, though a concurrent increment in light intensity noticeably decreased the lutein content. All the parameters were observed to be statistically significant. Best operating conditions for the growth of alga was evaluated to be as follows: light intensity, 200 μmol m−2 s−1; photoperiod, 12:12 h L D; and the aeration rate, 3 lpm. These conditions could substantially enhance the microalgal growth rate (0.82 day−1) and biomass production (665.89 mg). Specific lutein productivity and a recovery of 9.73 mg/L/day were achieved at a day light cycle of 16 h. According to the results of the experimental design, the optimum conditions led to a twofold increase in biomass and lutein productivity compared with unoptimized condition.

Two-phase method of cultivating Coelastrella species for increased production of lipids and carotenoids

Cultivation of Coelastrella sp. on Bold's basal medium (BBM) and Bold's triple nitrogen medium (B3N) over 12 days was performed for production of lipids and carotenoids by adjusting photoperiod and light intensity. The highest lipid content (30%) and maximum lipid productivity (77.83 mg/L/d) were attained on the 5th day of stage 2 in B3N media supplemented with 1% NaCl under light intensity of 4200 ± 100 Lux for 24 h. With the addition of 1% NaCl in B3N under light intensity of 4200 ± 100 Lux for 24 h (without any period of darkness) in stage 2, the biomass and lutein productivity were 1.8 and 1.6 folds of those under stage 1 in same medium. As judged by fatty acid profiles, the product, namely oil, met all the criteria stipulated for biodiesel in the international standard. We hypothesized that development of two phase cultivation may provide additional advantages which confirmed from the results obtained.

Defining the biosynthesis of ketocarotenoids in Chromochloris zofingiensis

Carotenoids are important pigments in photosynthetic organisms where they play essential roles in photoreception and photoprotection. Chromochloris zofingiensis is a unicellular green alga that is able to accumulate high amounts of ketocarotenoids including astaxanthin, canthaxanthin and ketolutein when growing heterotrophically or mixotrophically with glucose as a carbon source. Here we elucidate the ketocarotenoid biosynthesis pathway in C. zofingiensis by analyzing five algal mutants. The mutants were shown to have a single nucleotide insertion or substitution in β-carotene ketolase (BKT) gene 1, which resulted in a lack of ketocarotenoid production in Cz-bkt1-1, and decreased ketocarotenoid content in the other four mutants. These mutants accumulated much higher amounts of non-ketocarotenoids (β-carotene, zeaxanthin and lutein). Interestingly, the Cz-bkt1-5 mutant synthesized 2-fold the ketolutein and only 1/30 of the canthaxanthin and astaxanthin as its parent strain, suggesting that the mutated BKT1 exhibits much higher activity in catalyzing lutein to ketolutein but lower activity in ketolating β-carotene and zeaxanthin. Mutant and WT BKT2 gene sequences did not differ. Taken together, we conclude that BKT1 is the key gene involved in ketocarotenoid biosynthesis in C. zofingiensis. Our study provides insight into the biosynthesis of ketocarotenoids in green algae. Furthermore, Cz-bkt1 mutants may serve as a natural source for the production of zeaxanthin, lutein, and β-carotene.

Improved production of lutein and β-carotene by thermal and light intensity upshifts in the marine microalga Tetraselmis sp. CTP4

The industrial microalga Tetraselmis sp. CTP4 is a promising candidate for aquaculture feed, novel food, cosmeceutical and nutraceutical due to its balanced biochemical profile. To further upgrade its biomass value, carotenogenesis was investigated by testing four environmental factors, namely temperature, light intensity, salinity and nutrient availability over different growth stages. The most important factor for carotenoid induction in this species is a sufficient supply of nitrates leading to an exponential growth of the cells. Furthermore, high temperatures of over 30 °C compared to lower temperatures (10 and 20 °C) induced the accumulation of carotenoids in this species. Remarkably, the two different branches of carotenoid synthesis were regulated depending on different light intensities. Contents of β-carotene were 3-fold higher under low light intensities (33 μmol m−2 s−1) while lutein contents increased 1.5-fold under higher light intensities (170 and 280 μmol m−2 s−1). Nevertheless, highest contents of carotenoids (8.48 ± 0.47 mg g−1 DW) were found upon a thermal upshift from 20 °C to 35 °C after only two days at a light intensity of 170 μmol m−2 s−1. Under these conditions, high contents of both lutein and β-carotene were reached accounting for 3.17 ± 0.18 and 3.21 ± 0.18 mg g−1 DW, respectively. This study indicates that Tetraselmis sp. CTP4 could be a sustainable source of lutein and β-carotene at locations where a robust, euryhaline, thermotolerant microalgal strain is required.

Metabolic Engineering of Chlamydomonas reinhardtii for Enhanced β-Carotene and Lutein Production.

The metabolic engineering of Chlamydomonas reinhardtii, one of the fastest-growing microalgae, is a potential alternative for enhanced carotenoid productivity. CrtYB (phytoene-β-carotene synthase - PBS) gene from red yeast Xanthophyllomyces dendrorhous encodes for a bifunctional enzyme that harbours both phytoene synthase (psy) and lycopene cyclization (lcyb) activities. Heterologous expression of this bifunctional PBS gene led to 38% enhancement in β-carotene along with 60% increase in the lutein yields under low light conditions of 75 μmol photons m-2 s-1. Short Duration-High Light induction strategy led to overall 72% and 83% increase in β-carotene and lutein yield reaching up to 22.8 mg g-1 and 8.9 mg g-1, respectively. This is the first report of expression of heterologous bifunctional PBS gene resulting in simultaneous enhancement in β-carotene and lutein content in phototrophic engineered cells. Graphical Abstract.

Pilot-scale production of lutein using Chlorella vulgaris

Lutein is a carotenoid pigment which has applications in the food and nutraceutical sectors, both for its use as a colourant and for its applications as a nutraceutical. Microalgae are a promising source of lutein, however to meet market demand there is a need to develop technologies which can used for large-scale production. The effect of process conditions at a 5L scale were quantified, it was found that at low light intensities (160μmol photons m−2 s−1) the measured specific lutein concentration was 7.4±2.1mg g−1 which was greater than the concentration of 3.1±1.1mg g−1 obtained at higher (440μmol photons m−2 s−1) light intensities. Supplementation of the medium with nitrate led to significant increases in the maximum specific lutein concentration (10.4±5.5mg g−1) compared to medium without nitrate addition (4.3±2.9mg g−1). These conclusions were used to scale-up the process using 50L bubble column photo-bioreactors, it was found that the productivity was maximised (1.6mgL−1 day−1) using an air flow-rate of 1 vvm and 24h lighting. Finally, it was found that the process could be operated on a semi-continuous basis for 32 days, achieving high lutein concentrations (15–20mgL−1) with the performance of the system being consistent for this duration. Results from this work have clear application in the development of large-scale systems for the microalgal production of lutein.

The growth and lutein accumulation in heterotrophic Chlorella protothecoides provoked by waste Monascus fermentation broth feeding.

Although the potential of heterotrophic microalgae served as a sustainable source for lutein, it was still crucial to formulate a suitable medium to offset the cost involved in algal biomass cultivation while improve inherent lutein productivity. The objective of this study was to investigate the feasibilities of waste Monascus fermentation broth medium (MFBM) toward heterotrophic Chlorella protothecoides-enriched lutein. The results indicated that C. protothecoides subjected to MFBM batch feeding achieved 7.1g/L biomass and 7.27mg/g lutein. The resulting lutein productivity (7.34mg/L/day) represented 1.54-fold more than that of frequently used Basal medium. Concurrently, the effective metabolism and absorption of carbon, nitrogen, and phosphorus in MFBM by C. subellipsoidea cultivation make it easily complied with the permissible dischargeable limits for fermentation broth. When response to fed-batch culture mode, the biomass and lutein productivity peaked 20.4g/L and 9.11mg/L/day with concentrated MFBM feeding. Transcriptomics data hinted that MFBM feeding manipulated lutein biosynthesis key checkpoints (e.g., lycopene β-cyclase and lycopene ε-cyclase) while accelerated energy pathways (e.g., glycolysis and TCA cycle) to contribute such high lutein productivity in C. protothecoides. These encouraging findings not only provided indications in applying nutrient-rich fermentation broth for affordable microalgae cultivation but also presented possibilities in linking algal high value-added products like lutein with high-efficient biological nutrition removal from industrial fermentation processing.

Consolidated bioprocessing of wastewater cocktail in an algal biorefinery for enhanced biomass, lipid and lutein production coupled with efficient CO2 capture: An advanced optimization approach

We present a holistic approach in establishing a successful green integrated bio-refinery system with improved biomass, lipid and lutein productivity, while remediating wastewater and sequestering CO2 with potential biodiesel and healthcare applications. To achieve this we evaluated the effect of four process parameters: CO2% supply; acetate concentration; poultry litter waste (PLW) concentration; and light intensity on cultivation of Chlorella minutissma following the Taguchi's design of experimental technique. A four factors, three levels orthogonal array was adopted to cultivate Chlorella minutissma in specially developed waste water medium. Effect of the process parameters on biomass productivity, CO2 fixation rate, lipid content, lutein productivity and bioremediation capacity were determined. Results obtained from individual parametric combinations and Signal/Noise (S/N) ratio responses indicated S3 (5% CO2, 100 mg L−1 of acetate, 10 g L−1 of poultry litter, and 15, 000 lux of light intensity) combination as the optimum cultivation condition. Following the S3 combination a significant enhancement in biomass productivity (292 mg L−1 d−1) with exceedingly high CO2 fixation rate and photosynthetic efficiency (51.51 g L−1 d−1 of CO2; P.E: 15.81%) was achieved. A maximum of 169.29 mg L−1 d−1 of lipid with a balanced distribution of saturated and unsaturated fatty acids conformed to the international standard for biodiesel was achieved. Additionally, 7.21 mg L−1 d−1 of lutein productivity was also accomplished within 7 day of cultivation, while remediating up to 93-90% of nitrogenous and phosphate substrates. Statistically, the results reinforced our findings with the S/N responses and experimental observations for a particular property.

Nuances of microalgal technology in food and nutraceuticals: a review

PurposeThe purpose of this paper is to acquaint the readers with the insights regarding the interventions of microalgal technology for production of metabolites and functional ingredients from microalgae for food and nutraceutical application and exploration of microalgae biomass for food application.Design/methodology/approachVarious information databases such as journals, library catalogues and professional websites were used to collect information pertaining to application of microalgae in food and nutraceutical sector. Systematic review was made with recent studies covering the vital aspects of art of microalgae cultivation for metabolite production, functional ingredients from microalgae, market scenario and utilisation of microalgae biomass for the valorisation of the food products. Key points have been discussed after every section to highlight the practical implications to make this review more insightful for the readers.FindingsMicroalgal technology provides sustainable solution for its application in food and nutraceutical sector. The heart of metabolite production lies in the optimisation of cultivation conditions of microalgae. Wide array of functional components are obtained from microalgae. Microalgae offer an alternative source for omega-3 fatty acids. Microalgae is widely exploited for production of pigments, namely, ß-carotene, astaxanthin, lutein, phycocyanin and chlorophyll, that have important implication as natural colourants and nutraceuticals in food. Larger diversity of sterols found in microalgae confers bioactivity. Microalgae is finding its place in market shelves as nutraceuticals where its functional ingredients are in the form of powder, tablets, extract and beverages and in innovative products such as microalgae protein and fat, culinary algae oil and butter. Sprulina and Chlorella are popular choice for the supplementation of food products with microalgae biomass.Originality/valueThis is a comprehensive review that highlights the application of microalgal technology for the development of healthy food products and presents holistic intervention in food and nutraceutical sector.

Comparison of physics‐based and data‐driven modelling techniques for dynamic optimisation of fed‐batch bioprocesses

The development of digital bioprocessing technologies is critical to operate modern industrial bioprocesses. This study conducted the first investigation on the efficiency of using physics-based and data-driven models for the dynamic optimisation of long-term bioprocess. More specifically, this study exploits a predictive kinetic model and a cutting-edge data-driven model to compute open-loop optimisation strategies for the production of microalgal lutein during a fed-batch operation. Light intensity and nitrate inflow rate are used as control variables given their key impact on biomass growth and lutein synthesis. By employing different optimisation algorithms, several optimal control sequences were computed. Due to the distinct model construction principles and sophisticated process mechanisms, the physics-based and the data-driven models yielded contradictory optimisation strategies. The experimental verification confirms that the data-driven model predicted a closer result to the experiments than the physics-based model. Both models succeeded in improving lutein intracellular content by over 40% compared to the highest previous record; however, the data-driven model outperformed the kinetic model when optimising total lutein production and achieved an increase of 40-50%. This indicates the possible advantages of using data-driven modelling for optimisation and prediction of complex dynamic bioprocesses, and its potential in industrial bio-manufacturing systems.