Schizochytrium Sp Research Articles

Development of a Strategy to Improve the Stability of Culture Environment for Docosahexaenoic Acid Fermentation by Schizochytrium sp.

A stable culture environment is the key for optimal growth and metabolic activity of microorganisms, especially in marine species, and intermittent feeding during DHA production using Schizochytrium sp. generates an unstable culture environment. To investigate the effect of unstable culture environment on the cells' physiological status and DHA synthesis, fermentations with different feeding strategies were performed on the lab scale. The intermittent feeding strategy caused fluctuations of substrate concentration and osmotic pressure, which had a negative effect on cell division and product synthesis. The physiological status and metabolic level of Schizochytrium sp. were relatively stable under a continuous feeding strategy with a relatively stable substrate concentration of 20-25g/L, which was beneficial for the efficient transformation of substrate, leading to an improvement of DHA productivity. This strategy was further applied to pilot scale, whereby the DHA content, DHA productivity, convert ratio of glucose to lipid and DHA reached 55.02%, 320.17mg/(L·h), 24.35%, and 13.40%, respectively. This study therefore provides an efficient strategy for ensuring a stable culture environment for the production of DHA and similar metabolites. Graphical Abstract.

RETRACTED: Enteromorpha hydrolysate as carbon source for fatty acids production of microalgae Schizochytrium sp.

Numerous heterotrophic microalgae have the ability to accumulate lipids from various carbon sources. In this study, the dried Enteromorpha was pretreated by acidic hydrolysis and detoxification to increase monosaccharide content, and then the ability of Enteromorpha hydrolysate as a low-cost carbon source for the production of biomass and fatty acids by Schizochytrium sp. was first investigated. The results reveal that the total sugar contained in Enteromorpha hydrolysate were up to 43.93% of cell dry weight, which is a rich source of glucose. The strain was capable of utilizing the algal hydrolysate up to its maximum concentration of 100 g/L and could produce highest biomass (4.31 g/L) and total fatty acids yield (0.64 g/L), which were not significantly different from the maximum yields under pure glucose culture condition. Therefore, Enteromorpha hydrolysate can be used as a low-cost and effective carbon source for the biomass and fatty acids production of Schizochytrium sp. (C) 2020 Elsevier Ltd. All rights reserved.

The Delta 5,7‐Sterols and Astaxanthin in the Marine Microheterotroph Schizochytrium sp. S31

AbstractThe thraustochytrids, the heterotrophic marine microorganisms, have received increasing attention because of their capacity for the production of high‐value products such as docosahexaenoic acid (DHA), carotenoids, and sterols. In this study, three potential Δ5,7‐sterols, showing similar UV absorption spectra to that of ergosterol, in the thraustochytrid Schizochytrium sp. S31, were estimated by the ultraperformance liquid chromatography (UPLC) − APCI−MS/MS method. The proposed structures of three Δ5,7‐sterols were ergosta‐5,7,24(28)‐trien‐3β‐ol, ergosta‐5,7‐dien‐3β‐ol, and 24‐ethylcholesta‐5,7,22‐trien‐3β‐ol. The contents of astaxanthin, ergosterol, and the other three Δ5,7‐sterols in Schizochytrium sp. S31 during the cultivation performed in three separate batches were analyzed by a fast UPLC–PDA method. The results demonstrated that astaxanthin, ergosterol, and ergosta‐5,7‐dien‐3β‐ol were the predominant carotenoid and Δ5,7‐sterols, respectively, and their contents kept increasing during the growth and reached a maximum after 23 days of cultivation. The estimated maximum contents of astaxanthin and four Δ5,7‐sterols, including ergosterol, ergosta‐5,7‐dien‐3β‐ol, ergosta‐5,7,24(28)‐trien‐3β‐ol, and 24‐ethylcholesta‐5,7,22‐trien‐3β‐ol were 2.31, 4.02, 3.43, 0.30, and 0.97 mg g−1 dry biomass, respectively. These findings are different to other strains reported in the composition and accumulation of Δ5,7‐sterols and carotenoids. The present study suggests that Schizochytrium sp. S31 might be a promising marine microorganism for the productions of high‐value natural pigment astaxanthin, the provitamin D2 ergosterol, and the provitamin D4 ergosta‐5,7‐dien‐3β‐ol, and taken as a model organism to study the sterologenesis of the microorganisms because of its complexity of sterol compositions.

Optimization of cultivation conditions for efficient production of carotenoid-rich DHA oil by Schizochytrium sp. S31

The high carotenoid content in docosahexaenoic acid (DHA) oil may serve as an avenue to avoid DHA oxidation during storage. To obtain carotenoid-rich DHA oil from Schizochytrium sp. S31, the effects of several key medium components were investigated. Shake-flask experiment revealed that in optimal conditions, glycerol was used as the carbon source with 0.25 g/L of KH2PO4 and a C/N ratio of 75:20. Fed-batch cultivation further showed that a high lipid accumulation (30.81 g/L) with 497.56 μg/g carotenoid and 12.24 g/L DHA was obtained under the optimized conditions. The increased carotenoid content resulted in improved defense against environmental stress, as indicated by the catalase (CAT) and superoxide dismutase (SOD) activities. Further transcriptome analysis demonstrated that the synthesis pathway of β-carotene was enhanced during the lipid turnover stage, which suggested that more carotenoids were produced to reduce oxidative stress. This study presented an efficient strategy for DHA oil production with high carotenoid content.

THE EFFECT OF SUPPLEMENTATION OF MICROALGAE SCHIZOCHYTRIUM SP. AS A SOURCE OF DOCOSAHEXAENOIC ACID (DHA) ON DOGS WITH NATURALLY OCCURRING GINGIVITIS

The objective of this study was to evaluate the effects of the microalgae Schizochytrium sp., as a dietary source of docosahexaenoic acid (DHA), on dogs with gingivitis. Two diets containing 0 and 0.4% of microalgae Schizochytrium sp. were offered for 30 days to 12 randomly distributed adult Beagles to determine gingivitis. Gingivitis score and area were analyzed on days 0 and 30. Prior to the analysis, the area was gently cleaned with cotton wool on the surface of the crown of the teeth. There was no change in the gingivitis score (P>0.05). However, there was a reduction (P<0.05) in the area affected by gingivitis (day 30 - day 0) in animals supplemented with 0.4% microalgae Schizochytrium sp. The addition of 0.4% dietary microalgae reduced the area of gingivitis on dogs.

Regulation of lipid accumulation using nitrogen for microalgae lipid production in Schizochytrium sp. ABC101

Lipid-rich microalgae are a potential source for the bio-oil production. We isolated a novel oleaginous Thraustochytrid microalga from seawater, Schizochytrium sp. ABC101, and tested the effect of different growth conditions on its production of lipids. Batch fermentation experiments indicated that depletion of nitrogen led to lipid accumulation, and lipid accumulation led to increased cell size and decreased cell wall thickness. Based on these results, we tested three types of fed-batch fermentations (carbon and no nitrogen feeding, carbon and limited nitrogen feeding, carbon and sufficient nitrogen feeding) to examine the effect of adjusting the nitrogen supply on lipid accumulation. The limited nitrogen feeding provided the most efficient lipid production, with maxima after 60 h (dry cell weight [DCW]: 64.7 g/L, lipids: 25.4 g/L, docosahexaenoic acid [DHA]: 11.0 g/L). Use of corn steep liquor (CSL) as the sole nitrogen source also led to excellent performance, with maxima at 84 h (DCW: 86.0 g/L, lipids: 37.2 g/L, DHA: 16.7 g/L). In addition, use of CSL rather than yeast extract reduced the lipid production cost by 50%. Our results suggest that regulation of the nitrogen source improves the efficiency of microalgal lipid production and use of a low-cost nitrogen source reduces production costs.

Ultrasound-assisted extraction ameliorates the physicochemical properties of defatted mulberry seed protein to promote lipid production in Schizochytrium sp. SR21

To improve protein extraction rate and the utilization of mulberry seed protein (MSP) for biorefinery purposes, ultrasound-assisted extraction was used to treating defatted mulberry seed protein (DMSP) for enhancing lipid production in Schizochytrium sp. SR21. Under ultrasound irradiation with solid-liquid ratio of 1:40, temperature of 60 °C, time of 9 min, and output power of 600 W, the extraction rate of DMSP reached 77.05%, which was significantly improved than the blank control (18.70%) and microwave treatment (22.50%). Moreover, the solubility and emulsibility of DMSP treated by ultrasound were significantly improved; the assay results measured by near-infrared Raman Spectroscopy showed that ultrasound-assisted treatment could reduce the α-helix in the protein (reduced by 9.75%); correspondingly, structures of β-sheet and β-turn increased 1.33% and 3.01%; it indicated that ultrasound treatment changed the spatial arrangement of protein main chain atoms. The antioxidant activity test and the amino acid composition of defatted mulberry seed protein hydrolysate (DMSPH) showed that ultrasound-assisted treatment enhanced the antioxidant activity of the protein hydrolysate and there was no significant difference in amino acid composition between the DMSP and yeast extract. The DMSPH was used as nitrogen source to cultivate Schizochytrium sp. SR21 which showed that DMSPH promoted lipid production and the DHA content was 35.55%, which was better than the results of cultured with traditional nitrogen source; it indicates that DMSP can be used as nitrogen source in culture of microorganisms and further explanation of ultrasound-assisted treatment of modified MSP as an alternative nitrogen source achieved the goal of biorefinery.

Nutrient recovery from tofu whey wastewater for the economical production of docosahexaenoic acid by Schizochytrium sp. S31

Docosahexaenoic acid plays a vital role in human health as it is essential for the proper function of the nervous system and for visual functions. To decrease the cost of docosahexaenoic acid production by Schizochytrium, the cost of the medium should be further decreased. In this study, the use of tofu whey wastewater to culture Schizochytrium sp. for docosahexaenoic acid production was tested, with the goal of reducing the medium cost. The results indicated that tofu whey wastewater presented a better culture performance with respect to biomass, lipid, and docosahexaenoic acid production compared with three traditional media. Through simple pH adjustment, the biomass and docosahexaenoic acid productivity reached 1.89 and 0.24 g/L/day, respectively, which were much higher than those obtained using traditional medium. The removal efficiency of chemical oxygen demand, total nitrogen, and total phosphorus reached 64.7, 66.0, and 59.3%, respectively. Due to the rich nutrients in tofu whey wastewater, the use of extra nitrogen source was avoided and the total medium cost for docosahexaenoic acid production in cultures using tofu whey wastewater was <1/3 of that of traditional media. This result indicated that tofu whey wastewater is an effective and economic basal medium for docosahexaenoic acid production by Schizochytrium sp.

Effects of dietary supplementation with a microalga (Schizochytrium sp.) on the hemato-immunological, and intestinal histological parameters and gut microbiota of Nile tilapia in net cages

Nutritional improvements in intensive aquaculture production systems is necessary for the reduction of stress, maximum utilization of nutritional components, and expression of the genetic potential of fish. The objective of this study was to evaluate the hemato-immunological, and histological parameters and gut microbiota of Nile tilapia fed with the microalga Schizochytrium sp. Males of Nile tilapia were distributed among eight net cages (6 m3), and fed for 105 days with two diets: control (CON), without Schizochytrium sp., and supplemented (SUP), with 1.2% Schizochytrium sp. in the diet. The final weight, mortality, hematocrit, total erythrocyte count (RBC), hemoglobin, hematimetric indices, white blood cell count (WBC), total protein, and serum lysozyme were measured. Alterations in intestinal morphology were evaluated. The gut microbiota was evaluated with next-generation sequencing. No significant differences (p>0.05) were found in the final weight and mortality between diets. Regarding the hematological parameters, a difference (p<0.05) was detected only in RBC, with there being lower values in the SUP, although this group also showed a tendency toward having an increased mean corpuscular hemoglobin level. There were no differences (p>0.05) in total protein and serum lysozyme concentrations or in WBCs between diets, except for lymphocytes, which presented lower values (p<0.05) in the SUP, suggesting immunomodulation by the polyunsaturated fatty acids present in the microalga. There was no difference (p>0.05) in the intestinal morphology between diets. Metagenomic data indicated greater richness (represented by the Chao index) and a higher abundance of the bacterial phylum Firmicutes in the gut microbiota of the tilapia fed with the SUP diet, demonstrating that the digestion and use of the components of the microalga could influence the microbial community. The results indicated that the microalga had modulatory effects on blood cells and the intestinal microbiota, without affecting the structure and integrity of the intestinal villi.

Towards sustainable and ocean-friendly aquafeeds: Evaluating a fish-free feed for rainbow trout (Oncorhynchus mykiss) using three marine microalgae species

Aquaculture, the fastest growing food sector, is expected to expand to produce an additional 30 million metric tons of fish by 2030, thus filling the gap in supplies of seafood for humans. Salmonids aquaculture exploits the vast majority of fishmeal and fish oil rendered from ocean-dwelling forage fish. Most forage fish diverted to these commodities are human-food grade, and all are primary prey for marine predators. Rising costs, price volatility, and environmental sustainability concerns of using these commodities for aquaculture feed are driving the global search for alternatives, including marine microalgae originating from the base of marine food webs but produced in culture. We report the first evaluation of two marine microalgae, Nannochloropsis sp. and Isochrysis sp., for their potential to fully replace fishmeal and fish oil in diets of rainbow trout (Oncorhynchus mykiss), an important model for all salmonid aquaculture. We conducted a digestibility experiment with dried whole cells of Nannochloropsis sp. and Isochrysis sp., followed by a growth experiment using feeds with different combinations of Nannochloropsis sp., Isochrysis sp., and Schizochytrium sp. We found that digestibilities of crude protein, crude lipid, amino acids, fatty acids, omega 3 polyunsaturated fatty acids (n3 PUFA), docosahexaenoic acid (DHA), n6 (omega 6) PUFA in Isochrysis sp. were significantly higher than those in Nannochloropsis sp. Digestibility results suggest that for rainbow trout diets Isochrysis sp. is a better substitute for fishmeal and fish oil than Nannochloropsis sp. The lower feed intake by fish fed diets combining multiple microalgae, compared to fish fed the reference diet, was a primary cause of the growth retardation. In trout fillets, we detected an equal amount of DHA in fish fed fish-free diet and reference diet. This study suggests that Isochrysis sp. and Schizochytrium sp. are good candidates for DHA supplementation in trout diet formulations.

Surface-Modified Filter-Based Continuous Recovery of Microalgal Lipid-in-Solvent with High Recovery Efficiency, Long-Term Stability, and Cost Competitiveness.

Microalgal lipid-derived biofuels have been regarded as promising candidate materials to replace fossil fuels, but their production cost, especially for lipid extraction, still must be lowered substantially for field application. Although lipid extraction from concentrated wet microalgae using a nonpolar solvent is considered as a feasible method, an effective recovery method to regain the nonpolar solvent with microalgal lipid from the emulsified extraction mixture has not yet been addressed significantly. In this study, microalgal lipid is cost-efficiently recovered in continuous manner directly from the emulsified, highly concentrated extraction mixture by utilizing a surface-modified filter. The surface of a highly porous sponge filter is modified conformally by an oil-absorbing but water-repellent polymer coating via an initiated chemical vapor deposition (iCVD) process. Concentrated wet Schizochytrium sp. ABC101 microalgal cells are disrupted, and the microalgal lipid components are extracted out by adding n-hexane in the aqueous disrupted microalgae. The surface-modified filter is capable of selective permeation of the n-hexane phase with microalgal lipid while blocking the water-phase permeation simply by immersing the filter into the emulsified extraction mixture. The absorbed n-hexane phase is recovered in a continuous manner by pumping it out. The continuous filter-based recovery system shows a high recovery yield of 95% and an extremely high permeation flux of 2640 L m-2 h-1. Moreover, the recovery performance is maintained for more than 24 h without any filter-cleaning step. Techno-economic analysis of the method developed in this study with the conventional phase recovery methods shows that the rapid but highly cost-efficient filter-based recovery method will be a useful platform for scalable, continuous microalgae lipid production.

Enzymatic Synthesis of Ether Lipids Rich in Docosahexaenoic Acid with Squalene as Reaction Medium

AbstractUsing squalene as reaction medium was tried for the enzymatic synthesis of ether lipids rich in docosahexaenoic acid (DHA) via transesterification of alkylglycerols (AKG) obtained from shark liver oil and DHA‐enriched ethyl esters (DHA‐EE) from Schizochytrium sp. The effects of reaction time, temperature, molar ratio (AKG /DHA‐EE), and enzyme dosage were investigated. DHA conversion of 74.47% was achieved for 48 hours of reaction at 60 °C using a molar ratio of 1:2 and an enzyme dosage of 30% based on AKG in the presence of squalene with Lipozyme® 435 (Novozymes, Tianjin, China) as the catalyst. With a high boiling point, squalene could act as a solvent without being vaporized from the reaction system under vacuum and improve the operational stability of immobilized lipase, which may be useful for enzymatic reactions under vacuum for lipid modification with byproducts of low boiling points.

Exergy analysis for docosahexaenoic acid production by fermentation and strain improvement by adaptive laboratory evolution for Schizochytrium sp.

Exergy analysis is powerful tool for process optimization and mechanism analysis. In this study, exergy analysis was performed for docosahexaenoic acid (DHA) fermentation process. More than 86% of input exergy was contributed by glucose. The exergy of biomass was about 64.66% of the total output exergy when the phosphate concentration was 4 g L−1. The exergy efficiencies of DHA (ηDHA) for the starting strains and the evolved strains under high oxygen concentration, low temperature, and two-factor conditions were also investigated. The ηDHA in the collected experimental data was not more than 20.9%. It was proved that there was a positive correlation between ηDHA and the biomass yield. It was indicated that adaptive laboratory evolution (ALE) improved biomass yield which had the most important effect on enhancing ηDHA and DHA yield (or DHA productivity). It is necessary to improve ηDHA through process optimization and ALE in future.

The role of fluconazole in the regulation of fatty acid and unsaponifiable matter biosynthesis in Schizochytrium sp. MYA 1381

BackgroundSchizochytrium has been widely used in industry for synthesizing polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA). However, unclear biosynthesis pathway of PUFAs inhibits further production of the Schizochytrium. Unsaponifiable matter (UM) from mevalonate pathway is crucial to cell growth and intracellular metabolism in all higher eukaryotes and microalgae. Therefore, regulation of UM biosynthesis in Schizochytrium may have important effects on fatty acids synthesis. Moreover, it is well known that UMs, such as squalene and β-carotene, are of great commercial value. Thus, regulating UM biosynthesis may also allow for an increased valuation of Schizochytrium.ResultsTo investigate the correlation of UM biosynthesis with fatty acids accumulation in Schizochytrium, fluconazole was used to block the sterols pathway. The addition of 60 mg/L fluconazole at 48 h increased the total lipids (TLs) at 96 h by 16% without affecting cell growth, which was accompanied by remarkable changes in UMs and NADPH. Cholesterol content was reduced by 8%, and the squalene content improved by 45% at 72 h, which demonstrated fluconazole’s role in inhibiting squalene flow to cholesterol. As another typical UM with antioxidant capacity, the β-carotene production was increased by 53% at 96 h. The increase of squalene and β-carotene could boost intracellular oxidation resistance to protect fatty acids from oxidation. The NADPH was found to be 33% higher than that of the control at 96 h, which meant that the cells had more reducing power for fatty acid synthesis. Metabolic analysis further confirmed that regulation of sterols was closely related to glucose absorption, pigment biosynthesis and fatty acid production in Schizochytrium.ConclusionThis work first reported the effect of UM biosynthesis on fatty acid accumulation in Schizochytrium. The UM was found to affect fatty acid biosynthesis by changing cell membrane function, intracellular antioxidation and reducing power. We believe that this work provides valuable insights in improving PUFA and other valuable matters in microalgae.

Black Soldier Fly (Hermetia illucens) reared on roasted coffee by-product and Schizochytrium sp. as a sustainable terrestrial ingredient for aquafeeds production

Promoting circularity in the aquaculture sector through the conversion of great amount of organic by-products produced on land is a valuable strategy for a further development of the aquaculture sector. In this regard, insects represent a very promising example of bio-converting organisms; their application in aquafeeds, however, still faces possible limitations because of their lack in polyunsaturated fatty acids and the presence of chitin.The aim of the present study was to apply circularity to Black Soldier Fly (BSF) (Hermetia illucens) culture and to improve the insect's biomass fatty acid composition by culturing them on a land-produced by-product (coffee silverskin) enriched with a 10% Schizochytrium sp. The insect biomass was then used to formulate five fish diets containing 0, 25, 50, 75 and 100% of insect meal respect to fish meal, respectively. Diets were used for a feeding trial during zebrafish (Danio rerio) larval development (21 days) and a multidisciplinary approach including biometry, histology, gas chromatography, spectroscopy (FTIR), microbiota analyses and molecular biology was applied to better understand fish responses to the new diets. Results showed that the 50% substitution of fish meal with insect meal represented the best compromise between ingredient sustainability and proper fish growth and welfare. Fish fed with higher BSF inclusions (75 and 100%) showed a severe degree of hepatic steatosis, microbiota modification, a higher lipid content (FTIR), fatty acid modification and higher expression of both stress and immune response markers.

Study on Schizochytrium sp. improving the growth performance and non-specific immunity of golden pompano (Trachinotus ovatus) while not affecting the antioxidant capacity

A feeding experiment was conducted to determine the effects of Schizochytrium sp. on growth performance, antioxidant capacity and non-specific immunity in golden pompano (Trachinotus ovatus).Two diets were formulated with or without Schizochytrium sp. supplemented (D1:0% and D2: 3%) to feed fish for 8 weeks. Results showed that growth performance, feed intake and survival rate increased significantly with Schizochytrium sp. supplemented (P < 0.05). Feed coefficient rate (FCR) of golden pompano fed the diet supplemented with Schizochytrium sp. was significantly lower than that of fish fed the control diet (P < 0.05). No significant differences were found in antioxidant capacity both in transcriptional level, including nclear factor erythroid-2-related factor-2 (Nrf2), Kelch-like-ECH-associated protein (keap1), catalase (CAT), glutathione peroxidase (GSH-PX) and heme oxygenase 1 (HO-1) and enzyme activity, such as total antioxidant capacity (T-AOC), malondialdehyde (MDA) and superoxide dismutase (SOD) (P > 0.05). Gut amylase and lipase were significantly higher in dietary Schizochytrium sp. supplemented treatment than that in control group (P < 0.05). The relative peroxisome proliferator-activated receptor-α (PPARα) expression level in liver was significantly higher in Schizochytrium sp supplemented treatment than that in control one (P < 0.05). The mRNA expression of myeloid differentiation factor 88 (MyD88), IL-1R-associated kinases 4 (IRAK4), interferon regulating Factor 3 (IRF3), interferon regulating Factor 3(IRF7) and heat shock protein 70 (HSP70) were significantly lower in Schizochytrium sp. supplemented treatment than that in control one (P < 0.05). In Schizochytrium sp. supplemented diet, golden pompano had significantly longer villi length than that in control diet (P < 0.05); muscle thickness in Schizochytrium sp. supplemented diet was thicker than that in control one (P < 0.05) and there were more goblet cells in Schizochytrium sp. treatment (P < 0.05). After the rearing trial, an air exposure trial was conducted. Results showed that the air-exposure mortality (AEM) and mRNA expression level of Nrf2, keap1, CAT, GSH-PX and HO-1 showed no significant difference (P > 0.05). These results indicated that dietary Schizochytrium sp. improved the growth performance and non-specific immunity of golden pompano while made no difference to antioxidant capacity.

Inositol as a new enhancer for improving lipid production and accumulation in Schizochytrium sp. SR21.

Lipids produced from agricultural and industrial residues using oleaginous microorganisms for use as biofuels are attracting the attention of researchers due to their environmental benefits. However, low efficiencies and high costs limit their application to a certain extent. The present study is the first to use inositol as an enhancer to improve the production and accumulation of lipids during fermentation by the microalga Schizochytrium sp. SR21. The study aimed to maximize the production of lipids and docosahexaenoic acid (DHA) by optimizing the conditions of inositol addition into the fermentation medium. The corresponding key enzyme and metabolite profiles of SR21 were evaluated. The results indicated that the addition of 120mgL-1 of inositol to the medium at 48h improved lipid and DHA production by 13.90 and 20.82%, resulting in total concentrations of 22.86 and 8.53g/L, respectively. Moreover, the ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) increased by 23.38% and is consistent with the results of the metabolomic analysis. The activity of enzymes (i.e., PC, G6PDH, NADPH-ME, and ACL) related to fatty acid synthesis in strain SR21 also increased significantly (43.38%, 28.68%, 37.47%, and 19.87%, respectively). Metabolomic analysis also showed that inositol promoted lipid synthesis in SR21 and significantly increased the relative proportion of UFAs by affecting the citrate cycle and SFA and UFA metabolic pathways. Thus, inositol is an ideal enhancer of lipid production and accumulation by oleaginous microorganisms. Graphical abstract.

Lipid Distribution Pattern and Transcriptomic Insights Revealed the Potential Mechanism of Docosahexaenoic Acid Traffics in Schizochytrium sp. A-2.

Schizochytrium sp. A-2 is a heterotrophic marine fungus used for the commercial production of docosahexaenoic acid (DHA). However, the pattern of the distribution of DHA and how DHA is channeled into phospholipid (PL) and triacylglycerol (TAG) are unknown. In this study, we systematically analyzed the distribution of DHA in TAG and PL during the growth of the cell. The migration of DHA from PL to TAG was presumed during the fermentation cycle. DHA and docosapentaenoic acid were accumulated in both TAG and phosphatidylcholine (PC), whereas eicosapentaenoic acid was mainly deposited in PC. RNA seq revealed that malic enzyme may provide lipogenic NADPH. In addition, long-chain acyl-CoA synthase and acyl-CoA:lysophosphatidylcholine acyltransferase may participate in the accumulation of DHA in PL. No phosphatidylcholine:diacylglycerol cholinephosphotransferase was identified from the genome sequence. In contrast, phospholipid:diacylglycerol acyltransferase-mediated acyl-CoA-independent TAG synthesis pathway and phospholipase C may contribute to the channeling of DHA from PC to TAG.

Metabolic engineering to enhance biosynthesis of both docosahexaenoic acid and odd-chain fatty acids in Schizochytrium sp. S31

BackgroundDocosahexaenoic acid (DHA, C22:6) and odd-chain fatty acids (OCFAs, C15:0 and C17:0) have attracted great interest, since they have been widely used in food and therapeutic industries, as well as chemical industry, such as biodiesel production and improvement. The oil-producing heterotrophic microalgae Schizochytrium sp. 31 is one of main DHA-producing strains. Recently, it was found that Schizochytrium can also synthesize OCFAs; however, contents and titers of DHA and OCFAs in Schizochytrium are still low, which limit its practical application.ResultsIn this study, we found that acetyl-CoA carboxylase suffered from a feedback inhibition by C16-CoA in Schizochytrium, and relief of the inhibition resulted in improved both lipid content and the ratio of OCFAs in total fatty acids. Based on this finding, a novel strategy for elevating both DHA and OCFAs contents was established. First, the total lipid accumulation was increased by overexpressing a malic enzyme from Crypthecodinium cohnii to elevate NADPH supply. Second, the inhibition effect on acetyl-CoA carboxylase was relieved by overexpressing a codon-optimized ELO3 gene from Mortierella alpina, which encodes an elongase enzyme responsible for converting C16 into C18 fatty acids. After the above two-step engineering, contents of DHA and OCFAs were increased by 1.39- and 3.30-fold, reaching a level of 26.70 and 25.08% of dry cell weight, respectively, which are the highest contents reported so far for Schizochytrium. The titers of DHA and OCFAs were elevated by 1.08- and 2.57-fold, reaching a level of 3.54 and 3.32 g/L, respectively. Notably, the OCFAs titer achieved was 2.66-fold higher than the highest reported in Escherichia coli (1.25 g/L), implying potential value for industry application. To reveal the potential metabolic mechanism for the enhanced biosynthesis of both DHA and OCFAs, LC–MS metabolomic analysis was employed and the results showed that the pentose phosphate pathway and the glycolysis pathway were strengthened and intracellular propionyl-CoA concentration were also significantly increased in the engineered Schizochytrium, suggesting an increased supply of NADPH, acetyl-CoA, and propionyl-CoA for DHA and OCFAs accumulation.ConclusionsThe discovery provides a new source of OCFAs production, and proposes a new strategy to improve contents and titers of both DHA and OCFAs in Schizochytrium. These will be valuable for improving commercial potential of Schizochytrium and guiding the engineering strategy in other fatty acids producing heterotrophic microalga.

The Move toward Biopharma 4.0

Genetic Engineering & Biotechnology NewsVol. 39, No. 6 Bioprocessing TutorialThe Move toward Biopharma 4.0Insilico Biotechnology develops “smart” processes that benefit biomanufacturing through Digital TwinsShilpa Nargund, PhD, Kathrin Guenther, PhD, and Klaus MauchShilpa Nargund, PhDShilpa Nargund, PhD, is a Data Scientist & Business Development ManagerSearch for more papers by this author, Kathrin Guenther, PhDKathrin Guenther, PhD, is a Sr. Business Development ManagerSearch for more papers by this author, and Klaus MauchKlaus Mauch E-mail Address: (klaus.mauch@insilico-biotechnology.com) is the CEO & CTO at Insilico Biotechnology. Website: www.insilico-biotechnology.comSearch for more papers by this authorPublished Online:29 May 2019https://doi.org/10.1089/gen.39.06.18AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetailsCited byContinuous integrated manufacturing for biopharmaceuticals: A new paradigm or an empty promise?28 September 2022 | Biotechnology and Bioengineering, Vol. 120, No. 2Exploring the potential of machine learning for more efficient development and production of biopharmaceuticals11 August 2022 | Biotechnology Progress, Vol. 38, No. 6Arduino Soft Sensor for Monitoring Schizochytrium sp. Fermentation, a Proof of Concept for the Industrial Application of Genome-Scale Metabolic Models in the Context of Pharma 4.029 October 2022 | Processes, Vol. 10, No. 11Architectural and Technological Improvements to Integrated Bioprocess Models towards Real-Time Applications9 October 2022 | Bioengineering, Vol. 9, No. 10Artificial intelligence and machine learning applications in biopharmaceutical manufacturingTrends in Biotechnology, Vol. 349AI-ML applications in bioprocessing: ML as an enabler of real time quality prediction in continuous manufacturing of mAbsComputers & Chemical Engineering, Vol. 164Holistic Process Models: A Bayesian Predictive Ensemble Method for Single and Coupled Unit Operation Models29 March 2022 | Processes, Vol. 10, No. 4Modeling and optimization of bioreactor processesReprint of: Basic considerations for a digital twin of biointelligent systems: Applying technical design patterns to biological systemsCIRP Journal of Manufacturing Science and Technology, Vol. 34Computational Efforts for the Development and Scale-up of Antibody-Producing Cell Culture Processes1 January 2022Continuous downstream bioprocessing for intensified manufacture of biopharmaceuticals and antibodiesChemical Engineering ScienceBasic considerations for a digital twin of biointelligent systems: Applying technical design patterns to biological systemsCIRP Journal of Manufacturing Science and Technology, Vol. 31Digitalization in microbiology – Paving the path to sustainable circular bioeconomyNew Biotechnology, Vol. 59ChromaTech: A discontinuous Galerkin spectral element simulator for preparative liquid chromatographyComputers & Chemical Engineering, Vol. 141Digital Twins and Their Role in Model-Assisted Design of Experiments15 August 2020The Kalman Filter for the Supervision of Cultivation Processes11 November 2020History and Evolution of Modeling in Biotechnology: Modeling & Simulation, Application and Hardware PerformanceComputational and Structural Biotechnology Journal, Vol. 18The Rocky Road From Fed-Batch to Continuous Processing With E. coli20 November 2019 | Frontiers in Bioengineering and Biotechnology, Vol. 7 Volume 39Issue 6Jun 2019 InformationCopyright © by GEN PublishingTo cite this article:Shilpa Nargund, PhD, Kathrin Guenther, PhD, and Klaus Mauch.The Move toward Biopharma 4.0.Genetic Engineering & Biotechnology News.Jun 2019.53-55.http://doi.org/10.1089/gen.39.06.18Published in Volume: 39 Issue 6: May 29, 2019PDF download