Chlorella Cultivation Research Articles

Nutrient screening of Chlorella vulgaris and C. variabilis using high-throughput biolog phenotype arrays

Microalgae, particularly Chlorella species, are versatile microorganisms with significant scientific potential in various domains, including recombinant protein production, wastewater treatment, biofuel production, bio-fertilizers, food source, pharmaceuticals, and carbon capture. However, conventional growth media have often been the default choice for Chlorella cultivation. This study utilizes Biolog phenotype array plates to explore the growth responses of Chlorella vulgaris and Chlorella variabilis to a broad spectrum of carbon, nitrogen, phosphorus, and sulfur sources. The growth dynamics were captured by integrating the area under the OD-time curve. The results revealed growth preferences for both Chlorella species, emphasizing their unique nutrient source requirements and illuminated some unexpected growth behaviors. C. vulgaris exhibited equal preference for trehalose as glucose, and C. variabilis was unable to metabolize nitrate or sucrose, two staples of modified BBM media most commonly used for its cultivation. These findings contribute to a deeper understanding of the metabolic capacities of C. vulgaris and C. variabilis, informing potentially more efficient and tailored microalgal cultivation practices across diverse applications.

Effect of Media Formulations on Chlorophyll, Antioxidant Activity of Chlorella vulgaris and Its Potential as a Health Supplement

Graphical Abstract Highlight Research Chlorella indigenous from waters of Rokan River estuary was identified. The using of 4 chemicals KNO3, KH2PO4, MgSO4.7H2O and FeSO4.7H2O can reduce production cost and obtain an optimal medium formulation. The manipulated media was obtained can replace the commercial media of Chlorella Chlorella vulgaris contains high antioxidant activity. Abstract Chlorella is a microalga that is rich in chlorophyll and antioxidants so it has the potential to be a functional food or health supplement, however, the quality of Chlorella depends on the nutrient composition in cultivation. The research aimed to evaluate the effect of different formulations in Chlorella cultivation on the content of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids and antioxidants. Furthermore, to analyze the profile of amino acids, fatty acids and secondary metabolism in the best formulation. The experimental design used was a non-factorial Completely Randomized Design (CRD) with 5 formulations in Chlorella cultivation: control, F-1, F-2, F-3, and F-4 by manipulating the use of 4 chemicals: KNO3, KH2PO4, MgSO4.7H2O and FeSO4.7H2O. The data obtained were analyzed descriptively and analysis of variance (ANOVA). The results showed that F-1 treatment with the use of 1.50 KNO3, 1.25 KH2PO4, 1 MgSO4.7H2O and 0.0498 FeSO4.7H2O (g L-l) was the best treatment with the content of chlorophyll a 38.19 µg/mL, chlorophyll b 41.45 µg/mL, total chlorophyll 79.65 µg/mL, carotenoids 0.08 µg/mL, and antioxidants activity 49.52 mg/L (strong) which is the same as the control treatment. In addition, Chlorella cultivated with the F-1 formula has 17 amino acid profiles with a total of 301.52 mg/g, 7 fatty acids 84.32 mg/g, and secondary metabolites, namely alkaloid 109.471 mg/L, flavonoid 82.111 mg/L, saponin 1342.222 mg/L, tannin 411,591 mg/L, and phenolic 151.889 mg/L. Therefore, the F-1 formulation can be developed for large-scale Chlorella cultivation and applied as a health supplement.

Use of exogenous substrate in Chlorella cultivation: Strategy for biomass and polyhydroxybutyrate production

The aim of this study was to investigate the influence of exogenous carbon supplementation and nitrogen source reduction on Chlorella fusca LEB 111 growth, biomass composition, and polyhydroxybutyrate accumulation. First, assays were performed with 50 % and 25 % reduced nitrogen source concentrations (NaNO3). In the second stage, the influence of culture supplementation with 10, 20, and 30 mg L−1 D-xylose, associated with 50 and 25 % reductions in NaNO3, was evaluated. The experiments conducted with a 25 % reduction in NaNO3 and supplementation with 10 mg L−1 D-xylose resulted in a positive effect on the biomass productivity of C. fusca LEB 111, with production as high as 354.4 mg L−1 d−1. The maximum concentration of PHB extracted from C. fusca LEB 111 was 3.7 % (w w−1) and was obtained when the microalgae were cultivated with a 25 % of reduction in NaNO3 and supplementation of D-xylose at 20 mg L−1. Therefore, this study brings new perspectives regarding reducing the use of nutritional sources and using exogenous carbon sources in using microalgae to produce molecules of high biotechnological potential.

Implementation of mathematical models and algorithms in task control of the microalgae cultivation processes

This article considers the implementation of mathematical models and algorithms in the problems of controlling the process of chlorella cultivation. When building a control system, the following tasks are solved: collecting and primary processing of information, predicting the course of technological processes, optimizing regime parameters, managing a technological process, etc. One of the necessary conditions for the optimal conduct of the process of cultivating microorganisms is automatic control of the quality and composition of nutrients at the inlet, as well as control of the output indicators of the process. The frequency of solving control problems is set depending on the technological features, the control object, the mode of introducing the process, and also on the availability of a complex of technical means. As a result of the implementation of the proposed control system, the maximum ratio of the concentration of chlorella from its average value decreased by 23.8%. Thus, the control system for the cultivation of chlorella provides timely forecasting of the course of the technological process and the formation of control actions using a computing device, which contributes to an increase in the productivity of the cultivator by 8-12%.

Implementation of the developed models and algorithms in problems of control of the process of culturing of chlorella

The article considers the implementation of mathematical models and algorithms for hanging the efficiency of managing the chlorella cultivation process on the basis of the modeling algorithm of state parameters. One of the necessary conditions for the optimal conduct of the process of cultivating microorganisms is automatic control of the quality and composition of nutrients at the inlet, as well as control of the output indicators of the process. Based on the results of theoretical and experimental studies performed using modern methods and tools, as well as the positive results of industrial tests, it is possible to increase the efficiency of controlling the chlorella cultivation process on the basis of a modeling algorithm for state parameters.

The Role of Fe2o3 Nanoparticle Addition on Chlorella Cultivation: Effect of Culture Media on Growth and Biomass Composition

The Role of Fe2o3 Nanoparticle Addition on Chlorella Cultivation: Effect of Culture Media on Growth and Biomass Composition

Construction of mathematical modelling of a population of microalgae

This article devoted to the development of the mathematic model of the technological process of the chlorella cultivation process, its features and solving of this mathematic model. The Exponential growth of microalgae population under conditions of unlimited nutrient resources and population space proceeds at a rate proportional to the number of species of predominant cells and is described by the differential equation. In the presence of several inhibitors, specific velocity equations with the number of inhibitors can be used, but, as a rule, there are practically no elements acting as inhibitors in the cultivation of Chlorella microalgae. The modeling of this particular class of objects did not take into account the effect of inhibitors on the growth of microalgae. The consumption of nutrients to support the life of microalgae is described by the differential equation. In the course of this work, the processes of cultivation of microalgae were brought together into a system of equations. As a result, a system of differential equations of the technological process of Chlorella cultivation was obtained. Thus, the obtained system of equations describes the process of cultivation of microalgae and its technological process, implemented in a periodic mode.

Development of an algorithm for optimization of continuous technological process of cultivation of microorganisms

When implementing the tasks of controlling technological processes, finding the optimal control actions, and creating control algorithms that implement the optimal modes of technological processes, it is necessary to present the criterion of optimality in the form of a goal function, the extremum of which best meets the purpose of this object and expressed as - Relevant technical and economic indicators. The criterion of optimality should be an integral indicator that reflects the main aspects of production. Profit is most often taken as such a criterion for typical microbiological industries - as the most generalized indicator, reflecting almost all aspects of the enterprise. Possible criteria of optimality are analyzed in the form of technical and economic indicators of the process of cultivation of microorganisms, the extremum of which best meets the objectives of production and reflects the main aspects of the functioning of the control object. The analysis of possible modes of microalgae cultivation has been carried out. Two optimization algorithms are substantiated. The first one is based on random search method with an absolute bias, an algorithm for optimizing the process of cultivating microorganisms with continuous regeneration of the flow in one cultivator. The second is an algorithm for determining the optimal residence time of chlorella particles in multistage cultivators, focused on the method of dynamic programming implemented in Wellman's recurrence relation. The developed algorithm for operational forecasting and automatic control of the chlorella cultivation process allows, under given production conditions and the composition of nutrients, to increase the productivity of technological equipment and improve the quality of the target product, as well as to prevent in advance various unforeseen and emergency production situations.

Development and application of quantitative real-time PCR based on the mitochondrial cytochrome oxidase subunit I gene for early detection of the grazer Poterioochromonas malhamensis contaminating Chlorella culture

Poterioochromonas malhamensis is a flagellate grazer that readily contaminates Chlorella cultures and can have a devastating impact on them, especially in large-scale culture. Here, we developed a quantitative real-time polymerase chain reaction (qPCR) method to detect and quantify P. malhamensis from high-density Chlorella cultures. A set of primers specific to the mitochondrial cytochrome oxidase subunit I gene (COI) of P. malhamensis was screened and characterized comprehensively for specificity, sensitivity and applicability to the field samples. The results showed that the primers were sufficiently specific to distinguish P. malhamensis from a wide variety of micro-eukaryotes which often coexist with P. malhamensis in microalgal cultures, and could detect a very low concentration of P. malhamensis from high concentrations of Chlorella sorokiniana (106, 107, and 108C. sorokiniana cells mL−1). Moreover, the qPCR method was applied successfully to the monitoring of P. malhamensis population dynamics in Chlorella cultures in 100 L open ponds. Finally, the qPCR method was applied to the detection of this flagellate in the wider environment of the culture facility. It showed that the flagellate was widely distributed in the environment, and we speculate that Poterioochromonas in Chlorella cultures could originate from the air, the water, and the seed cultures. The qPCR method developed therefore proved to have the specificity and efficiency to be useful for early detection of P. malhamensis in industrial-scale Chlorella cultivation.

A novel lipids recovery strategy for biofuels generation on microalgae Chlorella cultivation with waste molasses

This study demonstrated a novel approach of lipids extraction with simultaneous biofuels conversion on microalgae Chlorella sorokiniana CY-1 cultivation using waste molasses as culture medium. The lipid extraction process was based on a hybrid liquid biphasic system (HLBS) which comprises of disruptive and extractive solvents in a single system. The microalgae cultivation with waste molasses showed a reduction in the chemical oxygen demand (COD), total suspended solid (TSS) and nitrate content on the waste medium (61.48 %, 63.94 % and 63.79 %, respectively). Additionally, a prompt lipids extraction with a recovery of 92.84 % and a cell disruption enhancement of 8.3-fold in the organic solvent phase was attained. The acid-treated C. sorokiniana CY-1 biomass showed a composition of carbon at 61.3 %, oxygen at 33.2 %, nitrogen at 5.5 % and potassium at 0.12 %. Sulphur content was not detected in the microalgae biomass and this had aided the production of fatty acids methyl ester (FAME) which was observed by a gas chromatographic-flame ionisation detector (GC-FID) profile. A disruptive-extraction method using acid assisted phase on HLBS showed potential for direct conversion of lipids into FAME to produce biofuels for engine combustion.

Ozonation as non-thermal option for bacterial load reduction of Chlorella biomass cultivated in airlift photobioreactor

The present study proposes the selective reduction of bacterial load in the microalgal cultures without affecting the microalgae. Bacteria was found to be symbiotically associated with microalgae and exponentially increased in the range of 103–1011 CFU mL-1 during Chlorella cultivation in the airlift photobioreactor. The bacterial load needs to be reduced to meet USFDA standards (∼103 CFU mL-1) for the use of microalgal biomass in food and feed applications. Ozone was evaluated as a non-thermal option for bacterial load reduction of Chlorella cultivated in the airlift photobioreactor. The results of ozonation w.r.t to time (5, 10, 15, 20, 25, and 30 min) and dissolved ozone concentrations (0.25, 0.49, 0.75, 0.99, and 1.25 mg of O3 L-1) showed a significant reduction of bacterial load in the range of 3 – 6.5 log. The bacterial disinfection kinetics of ozonation showed an overall second-order reaction with a rate constant (K) of 0.93 mg−1 min−1 L. Further, confocal laser microscopy imaging of Chlorella and its associated bacterial cells confirmed the selective and significant reduction of associated bacteria. The viability of the Chlorella cells were confirmed with trypan blue viability assay (∼99%) under a fluorescent microscope. The biomass quality with respect to metabolite integrity was also validated. In conclusion, ozonation can be a potential solution for selective reduction of bacterial load associated with Chlorella without affecting Chlorella cells viability.

Automatic control system for the technological process of chlorella cultivation

This article devoted to the implementation of mathematical models and algorithms in control problems of the chlorella cultivation process. The article gives us expanded concepts about the construction of the control functional – algorithmic structure, as well as the automation of various microbiological processes and productions, which based on modern computing devices, creation of a full-fledged complex for the task of chlorella mass cultivation process.When building the control system, problems are solved: collection and primary processing of information, prediction of technological processes progress, optimization of mode parameters, process control.Within the framework of these main tasks solutions have been found, which make it possible to facilitate the operator-technologist operational control or to implement reasonable management decisions depending on different production situations. For the considered class of objects, in particular the technological process of microalgae cultivation, the task of synthesis of control systems is to maintain the technological process at an optimal level that meets the technological and ecological standards of production.One of the necessary conditions for the optimal conduct of the process of cultivation of microorganisms is automatic control of the content and composition of nutrients at the entrance, as well as control of the output indicators of the process.The following technical tasks are also required to implement the management systems:- Improvement of local control and control systems (pH, T, light.);- Nutrient composition control, continuous medium circulation.Periodicity of control tasks solution is established depending on process features, control object, process introduction mode, as well as the availability of a set of hardware.As a result of the implementation of the proposed control system, the maximum ratio of chlorella concentration to its average value decreased by 23.8%.Thus, the control system of the chlorella cultivation process provides a timely prediction of the technological process and the formation of control actions using a computing device, which contributes to an increase in the productivity of the cultivator by 8-12%.Based on the theoretical and experimental studies performed as part of this work, the following main results were obtained:1. Based on the developed models and algorithms, a functional-algorithmic structure of a control system for the chlorella cultivation process is proposed, oriented towards solving the following problems: collecting and primary processing of information, predicting the progress of the technological process, optimizing operating parameters and controlling the course of the technological process.2. The implementation of the control system made it possible to increase the yield of chlorella from a unit of spent nutrients, to increase the productivity of the cultivator due to the strict maintenance of the optimal value of the residence time of the substrate particles in the apparatus.3. The results obtained make it possible to draw a conclusion about the adequacy of the constructed models for the real process, the correctness of the selected control actions and optimality criteria, as well as the efficiency and effectiveness of the developed algorithms for optimizing and controlling the technological process of chlorella production cultivation.

Photobioreactor Simulation for Microalgae Chlorella Cultivation in Process

Three-dimensional simulation of light fields in the photobioreactor for Chlorella cultivation was performed. It was shown, that light flux reduced due to the increase of optical density and growth of microalgae cells concentration. According to the fact that light intensity is an important factor, affecting growth rate and development of microalgae cells, process automation and light flux increase in dependence to Chlorella cells gain are needed to be introduced [1-3].

THE EFFECT OF GROWING CONDITIONS ON THE QUALITATIVE AND QUANTITATIVE INDICATORS OF CHLORELLA VULGARIS

The complex effect of two factors (the optimum ratio of nutrients of the medium and the electrostatic field) on the qualitative and quantitative indicators of Chlorella vulgaris was investigated. It is shown that the use of a medium with optimal concentrations of mineral substances and an electrostatic field with a voltage of 15 kV and an exposure time of 72 hours has a positive effect on growth rates, the size of microalgae cells and their viability, contributes to obtaining a culture with a density of 50 mln cells / ml 18 hours faster in comparison with the cultivation of generally accepted methods. It has been established that when two factors are influences on the cells of the Chlorella a mutagenic effect is not observed. Analysis of the microalgae culture grown under the influence of the studied factors showed that its chemical composition was consistent and with several indicators exceeded that of chlorella cultivation according to classical technologies. It was revealed that the activity of catalase and superoxide dismutase of microalgae grown in optimal conditions of the nutrient medium and the electrostatic field, significantly exceeded similar values of Chlorella vulgaris, which was not subjected to electrostatic stimulation. The high activity of the studied enzymes in Chlorella cells is shown in comparison with higher plants – components of bio-antioxidant preparations, such as Amaranthus paniculatus L. and Nicotiana tabacum L. According to the results of the toxicological study the absence of the content in Chlorella of the main poisonous substances for body animals and humans (mercury, arsenic) has been established. As a result of the research, it was proposed to use the established optimal parameters of both factors in the cultivation of C. vulgaris.

Pretreatment of pig manure liquid digestate for microalgae cultivation via innovative flocculation-biological contact oxidation approach

Liquid digestate with high concentration of organic matter and suspended solids cannot be directly used for microalgae cultivation. This study employed an innovative integrated approach, combining flocculation and biological contact oxidation (F-BCO), as a pretreatment to create a suitable environment for microalgae growth. The laboratory and pilot-scale experiments were both performed to verify operational performance. In F-BCO pretreatment, chemical oxygen demand (COD), NH3-N, and total phosphorus (TP) were reduced 55.0%, 46.1%, and 74.9%, respectively at pilot-scale in steady-state phase. It is further determined that the COD and TP removal were primarily attributed to flocculation, and NH3-N removal was mainly due to oxidation process (70%). The pretreated biogas slurry (BS) can be directly used for Chlorella cultivation, reaching a maximum accumulated biomass concentration of 3.3 g/L. The F-BCO process demonstrated a promising potential for pretreating BS to be a culture media for microalgae cultivation.

Enhanced MPBR with polyvinylpyrrolidone-graphene oxide/PVDF hollow fiber membrane for efficient ammonia nitrogen wastewater treatment and high-density Chlorella cultivation

Membrane fouling always as the main obstacle hinders wide application of membrane bioreactor (MBR). Development of antifouling membranes is a promising strategy to overcome this issue. In this study, novel polyvinylpyrrolidone (PVP)-graphene oxide (GO)/PVDF hollow fiber membrane with enhanced hydrophilicity and antifouling property was synthesized by assembling PVP-GO nanocomposites via chemical grafting method. The PVP-GO/PVDF membrane was successfully applied into algae-membrane photo-bioreactor (MPBR) with solids retention times (SRTs) of 30 d for high ammonia-nitrogen wastewater treatment at hydraulic retention times (HRTs) of 24 h. The permeability, removal performance and influence on extracellular polymeric substance (EPS) of algae-MPBR with modified PVDF membrane were compared to a control traditional system operated in parallel. Compared with pristine PVDF membrane, PVP-GO/PVDF membrane exhibited improved hydrophilicity (contact angle decreased from 97 to 62°), better permeability (1.7 times) and attractive flux recover rate (96%) in MPBR filtration, which was attributed to uniformly dispersed PVP-GO nanocomposites as spatial brushes for mitigating foulants on membrane surface. In terms of contaminants degradation, COD, NH4-N+ and NO3-N removal efficiency of algae-MPBR with modified membranes were kept above 97.8, 93.1 and 68.7%, much higher than traditional MBR. Moreover, remarkable reduction in hydrophobic proteins amount of EPS on fouling layer was observed for PVP-GO/PVDF membrane. The biomass concentration was maintained around 780 mg/L after 16 days and average biomass production rate reached as high as 45 mg/L d. These results indicated that PVP-GO/PVDF membrane exhibited superior antifouling performance for high-density microbes harvesting and efficient treatment for high ammonia-nitrogen wastewater.

Nutrient removal and microalgal biomass production from different anaerobic digestion effluents with Chlorella species

Potential of microalgal cultivation as an alternative approach to the treatment of anaerobic digestion (AD) effluents was examined using two representative Chlorella species, Chlorella vulgaris (CV) and Chlorella protothecoides (CP). Both species effectively removed NH4+-N from the AD effluents from four digesters treating different wastes under different operating conditions. In all experimental cultures on the AD effluents, NH4+-N (initial concentration, 40 mg/L) was completely removed within 10 days without residual NO3−-N or NO2−-N in batch mode. Compared to CP, CV showed greater biomass and lipid yields (advantageous for biodiesel production), regardless of the media used. Prolonged nitrogen starvation significantly increased the lipid accumulation in all cultures on the AD effluents, and the effect was more pronounced in the CV than in the CP cultures. On the other hand, compared to CV, CP showed significantly faster settling (advantageous for biomass harvesting) in all media. Our results suggest that the Chlorella cultivation on AD effluents under non-sterile, mixed-culture conditions may provide a viable way to manage and valorize the problematic effluents. Diverse bacteria derived from the AD effluents co-existed and presumably interacted with the Chlorella species in the cultures.

Identification of harmful protozoa in outdoor cultivation of Chlorella and the use of ultrasonication to control contamination

Contaminating organisms in mass cultivation present one of the major challenges that must be overcome for successful commercialization of algal biofuels. The present study identified a range of contaminating organisms in Chlorella cultures cultivated in outdoor raceway ponds at the Arizona Center for Algae Technology and Innovation (Mesa, AZ). Nineteen organisms or Operational Taxonomic Units (OTU) in the Chlorella culture were identified by a combination of microscopic observation and 18S rRNA denaturing gradient gel electrophoresis (DGGE). More detailed analyses identified these contaminating organisms as 2 fungi, 7 flagellates, 3 amoebae, 4 ciliates, 1 rotifer, and 2 large insects. Among them Poterioochromonas sp., a small flagellate, appeared to be one of the most harmful causing culture collapse. In order to control Poterioochromonas sp., various operational parameters and application strategies of ultrasonic treatment were investigated. During sixteen-day consecutive Chlorella cultivation in batch mode, the ultrasonication conditions of 6 L min−1 flow rate with the power of 495 W at 100% amplitude and a treatment frequency of once for 1 h every day, was proven to be the most effective in preventing Poterioochromonas outbreak in Chlorella culture with volume of 60 L. The above ultra-sonication method was also effective at destroying an unknown fungus, an amoeba (Acanthocystis sp.), and ciliates (a member of the family Orchitophryidae). Our findings can serve as a technical foundation for the application of ultrasonication to control some of the contaminating microorganisms in mass cultivation of microalgae including Chlorella.

Effect of Enzymatic Beech Fagus Sylvatica Wood Hydrolysate on Chlorella Biomass, Fatty Acid and Pigment Production

This work evaluates the possibility of applying enzymatic beech wood (Fagus sylvatica) hydrolysate as a feedstock for Chlorella sorokiniana growth, and fatty acid and pigment production. Beech wood solids were pretreated with NaOH at high temperature to partially remove xylose and Klason lignin, and enable production of glucose during subsequent enzymatic hydrolysis. Neutralized wood enzymatic hydrolysate containing glucose (TGP-Enz10), was tested on Chlorella growth during heterotrophic cultivation and compared with microalgae growth in a medium containing synthetic glucose (TGP). Results show that enzymatic hydrolysate enabled Chlorella growth in the dark for biomass, fatty acid and pigment production due to the presence of glucose, although the productivity obtained was smaller, if compared to heterotrophic cultivation in a synthetic TGP medium. Partial growth inhibition and diminished productivity in wood hydrolysate supplemented Chlorella culture was due to the presence of neutralized citrate buffer. Neutralized citrate buffer (TGP-Cit10) was found to partially inhibit heterotrophic growth and also strongly suppress mixotrophic growth in Chlorella culture. This buffer was also shown to alter fatty acid composition and to slightly affect ChlTotal/CarTotal ratio during heterotrophic cultivation. Heterotrophic Chlorella cultivation with TGP-Enz10 showed that wood enzymatic hydrolysate can constitute a potential feedstock for microalgae cultivation, although the composition of the buffer used during enzymatic hydrolysis should be taken into consideration.

Beech wood Fagus sylvatica dilute-acid hydrolysate as a feedstock to support Chlorella sorokiniana biomass, fatty acid and pigment production

This work evaluates the possibility of using beech wood (Fagus sylvatica) dilute-acid (H2SO4) hydrolysate as a feedstock for Chlorella sorokiniana growth, fatty acid and pigment production. Neutralized wood acid hydrolysate, containing organic and mineral compounds, was tested on Chlorella growth at different concentrations and compared to growth under phototrophic conditions. Chlorella growth was improved at lower loadings and inhibited at higher loadings. Based on these results, a 12% neutralized wood acid hydrolysate (Hyd12%) loading was selected to investigate its impact on Chlorella growth, fatty acid and pigment production. Hyd12% improved microalgal biomass, fatty acid and pigment productivities both in light and in dark, when compared to photoautotrophic control. Light intensity had substantial influence on fatty acid and pigment composition in Chlorella culture during Hyd12%-based growth. Moreover, heterotrophic Chlorella cultivation with Hyd12% also showed that wood hydrolysate can constitute an attractive feedstock for microalgae cultivation in case of lack of light.