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For biofuels and nutraceuticals, the green microalga Haematococcus pluvialis (Chlorophyceae) is a prospective source of biomass and lipids. This study examined how biomass production and lipid accumulation were affected by temperature (10 °C, 20 °C, and 30 °C) and potassium nitrate (KNO₃) concentrations (0.41 g/L, 0.31 g/L, 0.21 g/L, 0.10 g/L, and 0). The findings showed that the largest biomass (0.665 ± 0.200 g/L) was produced at a potassium nitrate concentration of 0.21 g/L at 20 °C, whereas the highest lipid content (46.31 ± 0.026% dry weight) was produced at a temperature without nitrate. Notably, a balanced result was obtained with a modest nitrate content (0.10 g/L) at 20 °C, yielding significant biomass (0.560 ± 0.136 g/L) and lipids (40.30 ± 0.012% dry weight). These results highlight how crucial it is to optimize cultivation settings in order to increase H. pluvialis's dual productivity, offering important new information for its industrial-scale use. By adjusting growing conditions, this research helps meet the need for renewable resources worldwide by promoting the production of high-value bioproducts and sustainable, commercially viable algae-based biofuels. [ABSTRACT FROM AUTHOR]

Research on enhancing the production of lipids, particularly polyunsaturated fatty acids that are considered important for health, has focused on improvement of metabolism as well as heterologous expression of biosynthetic genes in the oleaginous fungus Aspergillus oryzae. To date, the productivity and production yield of free fatty acids have been enhanced by 10-fold to 90-fold via improvements in metabolism and optimization of culture conditions. Moreover, the productivity of ester-type fatty acids present in triacylglycerols could be enhanced via metabolic improvement. Culturing A. oryzae in a liquid medium supplemented with non-ionic surfactants could also lead to the effective release of free fatty acids from the cells. The current review highlights the advancements made in this field so far and discusses the future outlook for research on lipid production using A. oryzae. I hope the contents are useful for researchers in this field to consider the strategy of increasing production of various valuable metabolites as well as lipids in A. oryzae. [ABSTRACT FROM AUTHOR]

Microalgae are considered valuable bioresources due to their ability to produce high lipid content and grow under a variety of environmental conditions, making them strong candidates for sustainable biofuel production. However, the economic feasibility of microalgae-based biofuels depends on optimizing growth conditions in large-scale cultivation systems. This study investigates the effects of varying inoculum cell concentrations on the growth, lipid yield, and fatty acid composition of the locally isolated microalga Chlorella sp. SW5 in 2 L and 5 L cultivation systems. The results indicate that higher inoculum concentrations generally enhance biomass accumulation, with the 2 L system achieving the highest growth rate of 0.42 ± 0.01 day⁻1 at an inoculum concentration of 10⁶ cells/mL. Interestingly, while higher inoculum concentrations reduced lipid production in the 2 L system, the 5 L system showed the highest lipid yield (51.23% ± 4.71% dry weight) at the highest inoculum concentration (10⁷ cells/mL). Despite its moderate growth rate, the 5 L culture with a starting inoculum concentration of 10⁷ cells/mL was selected for fatty acid profiling due to its superior lipid yield and productivity. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the culture produced a total of 93.18% C14-C18 fatty acids, with a profile dominated by saturated (56.33%) and monounsaturated (16.85%) fatty acids, which are essential for biodiesel quality. These findings provide valuable insights into the potential for scaling up microalgal systems for commercial biofuel production, highlighting strategies to optimize productivity. [ABSTRACT FROM AUTHOR]

Oleaginous microorganisms have the unique ability to accumulate lipids that can exceed 20% of their dry cell weight under certain conditions. Despite their potential for efficient lipid production, the metabolic pathways involved are not yet fully understood, largely due to the complexity of intracellular processes and the challenges in phenotypic prediction. This review synthesizes the latest research on the application of Genome‐scale Metabolic Network Models (GSMMs) to study oleaginous microorganisms, including bacteria, cyanobacteria, yeast, microalgae, and fungi, and provides a comprehensive analysis of how GSMMs have been utilized to decipher the metabolic mechanisms behind lipid accumulation and to identify key genes involved in lipid synthesis. The review highlights the role of GSMMs in predicting cellular behavior, optimizing metabolic engineering strategies, and discusses the future directions and potential of GSMMs in enhancing lipid production in microorganisms. This comprehensive overview not only summarizes the current state of research but also identifies gaps and opportunities for further investigation in the field. [ABSTRACT FROM AUTHOR]

ABSTRACT Oleaginous microorganisms have the unique ability to accumulate lipids that can exceed 20% of their dry cell weight under certain conditions. Despite their potential for efficient lipid production, the metabolic pathways involved are not yet fully understood, largely due to the complexity of intracellular processes and the challenges in phenotypic prediction. This review synthesizes the latest research on the application of Genome‐scale Metabolic Network Models (GSMMs) to study oleaginous microorganisms, including bacteria, cyanobacteria, yeast, microalgae, and fungi, and provides a comprehensive analysis of how GSMMs have been utilized to decipher the metabolic mechanisms behind lipid accumulation and to identify key genes involved in lipid synthesis. The review highlights the role of GSMMs in predicting cellular behavior, optimizing metabolic engineering strategies, and discusses the future directions and potential of GSMMs in enhancing lipid production in microorganisms. This comprehensive overview not only summarizes the current state of research but also identifies gaps and opportunities for further investigation in the field.

Microalgae are considered valuable bioresources due to their ability to produce high lipid content and grow under a variety of environmental conditions, making them strong candidates for sustainable biofuel production. However, the economic feasibility of microalgae-based biofuels depends on optimizing growth conditions in large-scale cultivation systems. This study investigates the effects of varying inoculum cell concentrations on the growth, lipid yield, and fatty acid composition of the locally isolated microalga Chlorella sp. SW5 in 2 L and 5 L cultivation systems. The results indicate that higher inoculum concentrations generally enhance biomass accumulation, with the 2 L system achieving the highest growth rate of 0.42 ± 0.01 day⁻1 at an inoculum concentration of 10⁶ cells/mL. Interestingly, while higher inoculum concentrations reduced lipid production in the 2 L system, the 5 L system showed the highest lipid yield (51.23% ± 4.71% dry weight) at the highest inoculum concentration (10⁷ cells/mL). Despite its moderate growth rate, the 5 L culture with a starting inoculum concentration of 10⁷ cells/mL was selected for fatty acid profiling due to its superior lipid yield and productivity. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the culture produced a total of 93.18% C14-C18 fatty acids, with a profile dominated by saturated (56.33%) and monounsaturated (16.85%) fatty acids, which are essential for biodiesel quality. These findings provide valuable insights into the potential for scaling up microalgal systems for commercial biofuel production, highlighting strategies to optimize productivity.

Microalgal lipids hold significant potential for the production of biodiesel and dietary supplements. To enhance their cost-effectiveness and commercial competitiveness, it is imperative to improve microalgal lipid productivity. Metabolic engineering that targets the key enzymes of the fatty acid synthesis pathway, along with transcription factor engineering, are effective strategies for improving lipid productivity in microalgae. This review provides a summary of the advancements made in the past 5 years in engineering the fatty acid biosynthetic pathway in eukaryotic microalgae. Furthermore, this review offers insights into transcriptional regulatory mechanisms and transcription factor engineering aimed at enhancing lipid production in eukaryotic microalgae. Finally, the review discusses the challenges and future perspectives associated with utilizing microalgae for the efficient production of lipids. [ABSTRACT FROM AUTHOR]

Currently, microalgae have become a marvelous and resource-friendly alternative source of advantageous bioproducts, such as lipids, carbohydrates, proteins, or other bioactive compounds. Because of the richness of microalgae in these high-value-added metabolites, still, it is an underdeveloped source of sustainable energy and food. There are some hurdles to profitable production, such as culture contamination and costly harvesting techniques. In the current work, a chrysophyte was isolated from dairy wastewater, identified as Poterioochromonas malhamensis based on its morphology and partial 18S rRNA gene sequences. This isolate was used to remediate dairy waste water (DWW) and to obtain neutral lipids (fatty acids) from microalgae. Microalgal growth was optimized by using different concentrations of DWW, supplemented with all the nutritive requirements for better progression and flourishment. Maximum biomass yield 1.478 g L−1 was achieved by optimized cultural conditions (different concentrations of DWW with BBM media). This strain showed high nitrate and phosphate removal efficiency (87.45% and 88.96%), respectively in 15 days. The experimental results highlighted that the lipid content and the chemical oxygen demand (COD) removal were 31.60% and 88.84%, respectively, and the lipid profile of isolated microalga was C16:0, C16:1, C18:0, C18:1, and C18:2 fatty acids. For growth and treatment purposes, 75% DWW with Bold’s Basal Medium (BBM) media showed better results. This is the first report of DWW treatment using the microalga Poterioochromonas malhamensis, as far as we are aware. Its cultivation prevented the spread of pollution of freshwater sources, remedied the DWW, and generated important lipids for industry.

Microalgal lipids hold significant potential for the production of biodiesel and dietary supplements. To enhance their cost-effectiveness and commercial competitiveness, it is imperative to improve microalgal lipid productivity. Metabolic engineering that targets the key enzymes of the fatty acid synthesis pathway, along with transcription factor engineering, are effective strategies for improving lipid productivity in microalgae. This review provides a summary of the advancements made in the past 5 years in engineering the fatty acid biosynthetic pathway in eukaryotic microalgae. Furthermore, this review offers insights into transcriptional regulatory mechanisms and transcription factor engineering aimed at enhancing lipid production in eukaryotic microalgae. Finally, the review discusses the challenges and future perspectives associated with utilizing microalgae for the efficient production of lipids.

Summary: Central metabolism produces amino and fatty acids for protein and lipids that establish seed value. Biosynthesis of storage reserves occurs in multiple organelles that exchange central intermediates including two essential metabolites, malate, and pyruvate that are linked by malic enzyme. Malic enzyme can be active in multiple subcellular compartments, partitioning carbon and reducing equivalents for anabolic and catabolic requirements. Prior studies based on isotopic labeling and steady‐state metabolic flux analyses indicated malic enzyme provides carbon for fatty acid biosynthesis in plants, though genetic evidence confirming this role is lacking. We hypothesized that increasing malic enzyme flux would alter carbon partitioning and result in increased lipid levels in soybeans.Homozygous transgenic soybean plants expressing Arabidopsis malic enzyme alleles, targeting the translational products to plastid or outside the plastid during seed development, were verified by transcript and enzyme activity analyses, organelle proteomics, and transient expression assays. Protein, oil, central metabolites, cofactors, and acyl‐acyl carrier protein (ACPs) levels were quantified overdevelopment.Amino and fatty acid levels were altered resulting in an increase in lipids by 0.5–2% of seed biomass (i.e. 2–9% change in oil).Subcellular targeting of a single gene product in central metabolism impacts carbon and reducing equivalent partitioning for seed storage reserves in soybeans. See also the Commentary on this article by Schwender, 239: 1539–1541. [ABSTRACT FROM AUTHOR]

In this work, microbial lipid production from non-detoxified Eucalyptus bark hydrolysate (EBH) with oleaginous xylose-utilizing Ashbya gossypii strains was explored. The best producing strain from a set of engineered strains was identified in synthetic media mimicking the composition of the non-detoxified EBH (SM), the lipid profile was characterized, and yeast extract and corn steep liquor (CSL) were pinpointed as supplements enabling a good balance between lipid accumulation, biomass production, and autolysis by A. gossypii. The potential of the engineered A. gossypii A877 strain to produce lipids was further validated and optimized with minimally processed inhibitor-containing hydrolysate and high sugar concentration, and scaled up in a 2 L bioreactor. Lipid production from non-detoxified EBH supplemented with CSL reached a lipid titer of 1.42 g/L, paving the way for sustainable single-cell oil production within the concept of circular economy and placing lipids as an alternative by-product within microbial biorefineries. [ABSTRACT FROM AUTHOR]

Mucor circinelloides has the ability to use a wide range of carbon sources to accumulate lipids. The different carbon sources have significantly influenced the total lipids through different metabolic pathways in oleaginous organisms. In the present study, the effects of exogenous oil (soybean oil) at different concentrations as an alternative carbon source on its fungal growth and lipid accumulation were investigated without changing fermentation culture conditions and the original C/N ratio, while using 100% glucose as a control. Total lipids and their fatty acid composition were determined by gas chromatography (GC). Moreover, the expression levels of desaturases genes involved in fatty acid biosynthesis were investigated in the studied strains using real-time fluorescence quantitative PCR. The results showed that a concentration of 35 g/L of glucose mixed with 24.3 g/L of soybean oil were the optimal carbon sources with constant carbon to nitrogen ratio. The biomass, lipid content and lipid yield of M. circinelloides grown in this medium increased rapidly in the early stage of fermentation, and the growth trend gradually slowed down in the late stage of fermentation, decreasing slightly after 72 h of fermentation. It was found that the highest biomass, total lipids, and lipid yields were significantly increased at 19.60 g/L, 42.62%, and 8.35 g/L (33.15%, 23.8%, and 65.10%), respectively. In contrast, the control group (those cultured on glucose as a single carbon source) was only 14.72 g/L, 34.41%, and 5.06 g/L, respectively. The critical step was in which α-linolenic acid (ALA) was stored from the exogenous oil in fungal cells supplying enough soybean oil with mixed substrates for fatty acids synthesis. The overexpression of the △12-desaturase gene in WJ11 significantly (P

Abstract Background Microalgae, with their high adaptability to various stress conditions and rapid growth, are considered excellent biomass resources for lipid production and biodiesel feedstocks. However, lipid yield and productivity of the natural strains are common bottlenecks in their large-scale use for lipid production, which can be overcome by evolving new strains using conventional and advanced mutagenic techniques. It is challenging to generate microalgae strains capable of high lipid synthesis through natural selection. As a result, random mutagenesis is currently considered a viable option in many scenarios. The objective of this study was to explore atmospheric and room temperature plasma (ARTP) as a random mutagenesis technique to obtain high lipid-accumulating mutants of a green microalga for improved biodiesel production. Results A green microalgal species was isolated from the Chinese Yellow Sea and identified as Parachlorella kessleri (OM758328). The isolated microalga was subsequently mutated by ARTP to obtain high lipid-accumulating mutants. Based on the growth rate and lipid content, 5 mutants (named M1, M2, M4, M5, and M8) were selected from 15 pre-selected mutants. These five mutants varied in their growth rate from 0.33 to 0.68 day−1, with the lipid content varying between 0.25 g/L in M2 to 0.30 g/L in M8 at 10th day of cultivation. Among the mutants, M8 showed the maximum biomass productivity (0.046 g/L/day) and lipid productivity (20.19 mg/L/day), which were 75% and 44% higher than the wild strain, respectively. The triglyceride (TAG) content of M8 was found to be 0.56 g/L at 16th day of cultivation, which was 1.77-fold higher than that of the wild strain. Furthermore, M8 had the highest saturated fatty acids (C16-18) with the lowermost polyunsaturated fatty acid content, which are favorable properties of a biodiesel feedstock according to international standards. Conclusion The mutant strain of P. kessleri developed by the ARTP technique exhibited significant improvements in biomass productivity, lipid content, and biodiesel quality. Therefore, the biomass of this mutant microalga could be a potential feedstock for biodiesel production.

Microalgae provide a potential alternative for high-value products. Integrating microalgae into the landfill leachate valorization process gives the opportunity to save water sources for biomass production. The aim of this study is to investigate the ability of landfill leachate to support microalgal biomass production and to explore how leachate affects the fatty acid and lipid content of microalgae. The wild "Chlorella sp." strain was isolated from a Tunisian natural lake and experimented in standard culture medium (Bold) as well as in different rates of landfill leachate. Results revealed that the leachate rate of 10% produced the highest amount of biomass (2.6 g L−1), which was significantly higher than Bold's medium. The final percentage of lipids recorded was 53% and 78% in Bold's medium and in leachate, respectively. Lipid productivity was stimulated 11 times more than obtained in Bold's medium with 823 mg L−1 d−1 in 10% leachate and 69.6 mg L−1 d−1 for Bold's medium. Characterization of the lipid extract using gas chromatography with a flame ionization detector (GC-FID) showed that around 90% of the total lipid content appeared mainly composed with saturated fatty acids such as palmitic acid (C16:0) and linoleic acid (C18:2) indicating a good quality of biodiesel. The leachate rate of 10% promotes the oleic, linoleic and linolenic acids known as omega 9, 6 and omega 3, respectively, by increasing its production to 10, 37 and 4%, respectively, while it was about only 5, 30 and 2%, respectively, in Bold's culture medium. It could be concluded that the Chlorella strain isolated from natural lake performs as a good tolerant organism to landfill leachate, and its culture in this effluent could be a potential source for lipid and biodiesel production. Using landfill leachate as a culture medium gives the opportunity to save water sources for microalgal biomass production. Growth and lipid production performances of a wild Chlorella sp.microalgae using landfill leachate as a culture medium [ABSTRACT FROM AUTHOR]

Currently, microalgae have become a marvelous and resource-friendly alternative source of advantageous bioproducts, such as lipids, carbohydrates, proteins, or other bioactive compounds. Because of the richness of microalgae in these high-value-added metabolites, still, it is an underdeveloped source of sustainable energy and food. There are some hurdles to profitable production, such as culture contamination and costly harvesting techniques. In the current work, a chrysophyte was isolated from dairy wastewater, identified as Poterioochromonas malhamensis based on its morphology and partial 18S rRNA gene sequences. This isolate was used to remediate dairy wastewater (DWW) and to obtain neutral lipids (fatty acids) from microalgae. Microalgal growth was optimized by using different concentrations of DWW, supplemented with all the nutritive requirements for better progression and flourishment. Maximum biomass yield 1.478 g L−1 was achieved by optimized cultural conditions (different concentrations of DWW with BBM media). This strain showed high nitrate and phosphate removal efficiency (87.45% and 88.96%), respectively in 15 days. The experimental results highlighted that the lipid content and the chemical oxygen demand (COD) removal were 31.60% and 88.84%, respectively and the lipid profile of isolated microalga was C16:0, C16:1, C18:0, C18:1, and C18:2 fatty acids. For growth and treatment purposes, 75% DWW with Bold’s Basal Medium (BBM) media showed better results. This is the first report of DWW treatment using the microalga Poterioochromonas malhamensis, as far as we are aware. Its cultivation prevented the spread of pollution of freshwater sources, remedied the DWW, and generated important lipids for industry. [ABSTRACT FROM AUTHOR]

Low biomass yield and nutrient removal efficiency are problems challenging the employment of microorganisms for wastewater remediation. Starch processing effluent (SPE) was used as a fermentation substrate to co-culture Chlorella vulgaris and Rhodotorula glutinis for biofuel feedstock production. Co-culture options were compared, and the optimal conditions were identified. The result shows that microalgae and yeast should be inoculated simultaneously at the beginning of SPE-based fermentation to achieve high biomass yield and the optimal inoculation ratio, light intensity, and temperature should be 2:1, 150 μmol/m2/s, and 25 °C, respectively. Under the optimal conditions, the lipid yield of microorganisms was 1.81 g/L and the carbon–conversion ratio reached 82.53% while lipid yield and the carbon–conversion ratio in a monoculture fell in the range of 0.79–0.81 g/L and 55.93–62.61%, respectively. Therefore, compared to the monoculture model, the co-fermentation of Chlorella vulgaris and Rhodotorula glutinis in starch processing effluent could convert nutrients to single-cell oil in a more efficient way. It should be noted that with the reduced concentration of residual organic carbon in effluent and the increased carbon–conversion ratio, co-fermentation of microalgae and yeast can be regarded as a promising and applicable strategy for starch processing effluent remediation and low-cost biofuel feedstock production. [ABSTRACT FROM AUTHOR]

Oleic acid is increasingly required in many industries, causing the indiscriminate extension of land for the cultivation of certain agricultural products to extract their oil. The current contribution aimed to cultivate Candida wangnamkhiaoensis (CW) for the production of lipids and determine the profile of fatty acids in these lipids. The lipid yield was compared in the yeast when using glucose or glycerol as the substrate, in both cases being over 24%. The main fatty acids in the oil derived from CW were oleic, palmitic, stearic, and linoleic acid. The fatty acid composition of the oil from CW was very similar to that of avocado oil and resembled that of olive oil and palm oil. The advantages of cultivating CW include its relatively high percentage of oleic acid and the balance of other fatty acids, its capacity to generate lipids in a short time (48–72 h), the controlled environment of production (versus the variability of the cultivation of agricultural products), and the relatively limited surface area required. CW shows potential as an alternative and economical source of oleic acid for the food, drug, cosmetics, lubricant, and biofuel industries, and does not require the alteration of large extensions of land. [ABSTRACT FROM AUTHOR]

Abstract Background Schizochytrium sp. is a heterotrophic, oil-producing microorganism that can efficiently produce lipids. However, the industrial production of bulk chemicals using Schizochytrium sp. is still not economically viable due to high-cost culture medium. Replacing glucose with cheap and renewable lignocellulose is a highly promising approach to reduce production costs, but Schizochytrium sp. cannot efficiently metabolize xylose, a major pentose in lignocellulosic biomass. Results In order to improve the utilization of lignocellulose by Schizochytrium sp., we cloned and functionally characterized the genes encoding enzymes involved in the xylose metabolism. The results showed that the endogenous xylose reductase and xylulose kinase genes possess corresponding functional activities. Additionally, attempts were made to construct a strain of Schizochytrium sp. that can effectively use xylose by using genetic engineering techniques to introduce exogenous xylitol dehydrogenase/xylose isomerase; however, the introduction of heterologous xylitol dehydrogenase did not produce a xylose-utilizing engineered strain, whereas the introduction of xylose isomerase did. The results showed that the engineered strain 308-XI with an exogenous xylose isomerase could consume 8.2 g/L xylose over 60 h of cultivation. Xylose consumption was further elevated to 11.1 g/L when heterologous xylose isomerase and xylulose kinase were overexpressed simultaneously. Furthermore, cultivation of 308-XI-XK(S) using lignocellulosic hydrolysates, which contained glucose and xylose, yielded a 22.4 g/L of dry cell weight and 5.3 g/L of total lipid titer, respectively, representing 42.7 and 30.4% increases compared to the wild type. Conclusion This study shows that engineering of Schizochytrium sp. to efficiently utilize xylose is conducive to improve its utilization of lignocellulose, which can reduce the costs of industrial lipid production.

Sucrose non-fermenting 1 (SNF1) protein kinase plays an important role in the utilization of selective carbon sources and regulation of lipid metabolism. In order to further explore the function of SNF1 in regulating lipid accumulation by responding nutritional signals from non-glucose carbon sources, in the present study, the lipid production and SNF1 transcriptional levels of Mucor circinelloides were analyzed and compared on different carbon sources. The results indicated that M. circinelloides could effectively utilize some secondary metabolic carbon sources of monosaccharides and disaccharides for growth and lipids production, such as fructose, maltose and galactose. Snf-β subunit was associated with the regulation of lipid metabolism in response to nutritional signals from different carbon sources. This is the first report on the transcriptional analysis of SNF1 subunits on different carbons metabolism in oleaginous filamentous fungi. This research has suggested that genetic engineering of SNF1 subunits will alter the lipid production of M. circinelloides from alternative carbon sources. [ABSTRACT FROM AUTHOR]

The study evaluated the use of Chlorella vulgaris for bioremediating hydroponic wastewater and producing biomass under different cultivation modes and to explore the economic implications of microalgal biofuels. Total nitrogen (TN) removal efficiency was 98.5% in mixotrophic conditions and 96% in heterotrophic conditions, and total phosphorus (TP) was completely removed (>99%) in both cultivation conditions. TN removal was higher for that which was cultivated under the mixotrophic mode of cultivation. The maximum biomass production (1.26 g/L) and biomass productivity (0.1108 g/L/day) were also reported for mixotrophic conditions. Lipid content was slightly higher for that which was cultivated under heterotrophic conditions: 33 wt% on an ash-free dry weight (AFDW) basis. The highest lipid production was obtained under mixotrophic growth (0.341 g/L). Higher net profit was obtained for both mixotrophic and heterotrophic cultivations: 30.6 million $/year for a plant capacity of 3.29 × 104 tone/year and 30.12 million $/year for a plant capacity of 3.17 × 104 tone/year respectively. Sensitivity analysis showed that biodiesel and nutritious supplements from soluble protein have the greatest impact on the process economics regarding mixotrophic cultivation, while biodiesel and feeds from insoluble protein have the largest effect on the process economics regarding heterotrophic and autotrophic cultivations. HIGHLIGHTS C. vulgaris was cultivated in hydroponic wastewater to remove nutrients and to produce lipid and biomass.; C. vulgaris showed higher TN removal efficiency under mixotrophic growth (TN: 98.5%).; Maximum lipid content was reported for heterotrophic growth (33 wt% AFDW).; Mixotrophic cultivation showed maximum biomass production (1.26 g/L) and biomass productivity (0.1108 g/L/day).; The best economic benefits were obtained for mixotrophic (net profit: 30.6 million $/year) and heterotrophic (net profit: 30.12 million $/year) cultivations.;

Bioenergy production from algae has gained significant attention due to its potential as a sustainable and renewable energy source. This research investigates the optimization of bioenergy production by focusing on bioreactor design to enhance the efficiency of algal biomass growth and lipid extraction. The study involves analyzing key bioreactor parameters such as light intensity, nutrient concentration, pH levels, and carbon dioxide (CO₂) supply. Experimental results demonstrated a 25% increase in lipid production through optimized conditions, showing promising improvements in biofuel yield. The findings of this research provide valuable insights into the potential scalability of algae-based bioenergy systems.

This article is a Commentary on Morley et al. (2023), 239: 1834–1851. [ABSTRACT FROM AUTHOR]

The interest in microorganisms to produce microbial lipids at large-scale processes has increased during the last decades. Rhodosporidium toruloides-1588 could be an efficient option for its ability to simultaneously utilize five- and six-carbon sugars. Nevertheless, one of the most important characteristics that any strain needs to be considered or used at an industrial scale is its capacity to grow in substrates with high sugar concentrations. In this study, the effect of high sugar concentrations and the effect of ammonium sulfate were tested on R. toruloides-1588 and its capacity to grow and accumulate lipids using undetoxified wood hydrolysates. Batch fermentations showed a catabolic repression effect on R. toruloides-1588 growth at sugar concentrations of 120 g/L. The maximum lipid accumulation was 8.2 g/L with palmitic, stearic, oleic, linoleic, and lignoceric acids as predominant fatty acids in the produced lipids. Furthermore, R. toruloides-1588 was able to utilize up to 80% of the total xylose content. Additionally, this study is the first to report the effect of using high xylose concentrations on the growth, sugar utilization, and lipid accumulation by R. toruloides-1588. [ABSTRACT FROM AUTHOR]

In the present study, Synechococcus elongatus and Anabaena, two cyanobacterial species were cultured using different media conditions such as ASN III, modified ASN III, BG-11, and BBM for the enrichment of biomass and lipid productivity. The experimental result clearly shows that BG 11 was the efficient and cost-effective medium for both the isolated cyanobacterial species such as Synechococcus elongatus and Anabaena. The influence of organic carbon sources on biomass and lipid productivity of the selected cyanobacterial species were studied when cultivated in a BG-11 medium using different organic carbon sources such as sucrose, glucose, sodium acetate and glycerol under mixotrophic conditions. Based on the experimental results, the isolated cyanobacterial strain Synechococcus elongatus and Anabaena showed an enriching effect on lipid production under mixotrophic conditions, but whereas Synechococcus elongatus showed a significant effect three times greater lipid productivity compared with Anabaena cyanobacterial strain, by the addition of glycerol as a supplement to the culture media. [ABSTRACT FROM AUTHOR]

Lipid extraction from microbial and microalgae biomass requires the separation of oil-rich cells from the production media. This downstream procedure represents a major bottleneck in biodiesel production, increasing the cost of the final product. Flocculation is a rapid and cheap system for removing solid particles from a suspension. This natural characteristic is displayed by some microorganisms due to the presence of lectin-like proteins (called flocculins/adhesins) in the cell wall. In this work, we showed, for the first time, that the heterologous expression of the adhesin Cfl1p endows the oleaginous species Cutaneotrichosporon oleaginosus with the capacity of cell flocculation. We used Helm's test to demonstrate that the acquisition of this trait allows for reducing the time required for the separation of lipid-rich cells from liquid culture by centrifugation without altering the productivity. This improves the lipid production process remarkably by providing a more efficient downstream. [ABSTRACT FROM AUTHOR]

POME is an excellent cultivation medium for the production of microalgae because it includes high macro and micronutrients. Nevertheless, microalga cultivation is laborious to maintain under outdoor condition. The aim of this reseasch was to evaluate the potency of co-cultivation strategy to improve growth and lipid production of mixed algae when growing on POME under dynamic outdoor condition. Cultivation was done in outdoor condition by comparing synthetic medium and POME medium, and optimizing the enviromental and nutritional conditions by using Box-behnken response surface methodology (RSM). Results showed that high growth rate (0.35/d) and lipid (40%) were achieved when 75% POME fraction, 30 PSU salinity, and 450 mg/L urea were used. The increasing POME fraction and urea addition enhanced SFA formation to MUFA and PUFA in the fatty acid profiles. We conclude that co-cultivation strategy on POME could promote growth rate and lipid production of mixed algae under outdoor condition. [ABSTRACT FROM AUTHOR]

An effective prototype of photobioreactor namely hollow fiber membrane bioreactor is employed to produce algal biomass for biofuel production. The effect of two-stage cultivation system on the biomass productivity and lipid production is studied using freshwater green microalga Tetradesmus obliquus MT188616.1. The hybrid system combines exponential biomass production in hollow fiber membrane photobioreactor (HFMPBr) and a coordinated high-lipid stimulation phase in nitrogen-deprived medium by the shake flask method. This work is proposed to examine the usefulness of HFMPBr module to enhance the microalgal growth rate through the effective mass transfer by standardizing the culture medium re-circulation flow rates (5 – 45 mL min−1) through the hollow fiber membranes. Cultivation is carried out at continuous mode in HFMPBr containing polysulfone fabricated membranes at fixed light intensity of 50 µmol m−2 s−1 and temperature at 28 °C. Biomass productivity and specific growth rate obtained are 0.44 g L−1d−1 and 1.61 µ d−1 with a lipid yield of 0.1 g L− 1. The key operating parameter i.e., liquid flow rate is optimized based on biomass production. The highest biomass concentration is produced at the flow rate of 45 mL min−1. The results showed that HFMPBr module is a better choice for the algal-cultivation to obtain higher biomass yield. The effect of two-stage cultivation system on the growth rate, biomass productivity, and lipid yield was studied in freshwater green microalga Tetradesmus obliquus MT188616.1. The hybrid system combines exponential biomass production in hollow fiber membrane photobioreactor (HFMPBr) and a coordinated high-lipid stimulation phase in nitrogen deprived medium by the shake flask method. The algal cultivation was carried out at continuous mode in HFMPBr containing polysulfone fabricated membranes at fixed light intensity of 50 µmol m−2 s−1 and temperature at 28 °C. Biomass productivity and specific growth rate obtained were 0.44 g L−1d−1 and 1.61 µ d−1 with a lipid yield of 0.1 g L− 1. The key operating parameter i.e., liquid flow rate was optimized based on biomass production. The highest biomass concentration was produced at the highest flow rate of 45 mL min−1, whereas the lowest biomass was at the lowest flow rate of 5 mL min−1. The results showed that HFMPBr module was a better choice for the cultivation of Tetradesmus obliquus MT188616.1 to obtain higher biomass yield. [Display omitted] • Integrated HFMPBr and shake flask approach to attain higher lipid yield of algae. • Optimized salt medium flow rate in HFMPBr for continuous algal growth. • Attained efficient delivery of nutrients via membranes for algal growth and waste removal by maintaining optimal flow rate. • Achieved close to 0.44 gL-1day-1 biomass productivity under 45 mL min-1 flow rate during 10 h light – 14 h dark photoperiod. [ABSTRACT FROM AUTHOR]

Background: Microalgae, with their high adaptability to various stress conditions and rapid growth, are considered excellent biomass resources for lipid production and biodiesel feedstocks. However, lipid yield and productivity of the natural strains are common bottlenecks in their large-scale use for lipid production, which can be overcome by evolving new strains using conventional and advanced mutagenic techniques. It is challenging to generate microalgae strains capable of high lipid synthesis through natural selection. As a result, random mutagenesis is currently considered a viable option in many scenarios. The objective of this study was to explore atmospheric and room temperature plasma (ARTP) as a random mutagenesis technique to obtain high lipid-accumulating mutants of a green microalga for improved biodiesel production. Results: A green microalgal species was isolated from the Chinese Yellow Sea and identified as Parachlorella kessleri (OM758328). The isolated microalga was subsequently mutated by ARTP to obtain high lipid-accumulating mutants. Based on the growth rate and lipid content, 5 mutants (named M1, M2, M4, M5, and M8) were selected from 15 pre-selected mutants. These five mutants varied in their growth rate from 0.33 to 0.68 day-1, with the lipid content varying between 0.25 g/L in M2 to 0.30 g/L in M8 at 10th day of cultivation. Among the mutants, M8 showed the maximum biomass productivity (0.046 g/L/day) and lipid productivity (20.19 mg/L/day), which were 75% and 44% higher than the wild strain, respectively. The triglyceride (TAG) content of M8 was found to be 0.56 g/L at 16th day of cultivation, which was 1.77-fold higher than that of the wild strain. Furthermore, M8 had the highest saturated fatty acids (C16-18) with the lowermost polyunsaturated fatty acid content, which are favorable properties of a biodiesel feedstock according to international standards. Conclusion: The mutant strain of P. kessleri developed by the ARTP technique exhibited significant improvements in biomass productivity, lipid content, and biodiesel quality. Therefore, the biomass of this mutant microalga could be a potential feedstock for biodiesel production. [ABSTRACT FROM AUTHOR]

Abstract Rhodosporidium toruloides is a useful oleaginous yeast, but lipids production is affected by various factors including nutrients in the culture medium. Herein, the R-ZL2 high-yield mutant strain was used to investigate the effects of different carbon sources (sucrose, glucose, xylose), nitrogen sources (ammonium sulphate, ammonium nitrate), and C/N ratio on lipids production capacity, get the following conclusion (1) Compared with glucose and xylose, sucrose was a superior carbon source for lipids production; (2) When using ammonium sulphate as the nitrogen source, a C/N ratio of 200:1 achieved the highest biomass, lipids production and lipids content (10.7 g/L, 6.32 g/L and 59%, respectively), and lipids produced under different C/N conditions have potential for biodiesel production (except for C/N = 40 and C/N = 80); (3) When using ammonium nitrate as the nitrogen source, a C/N ratio of 200:1 achieved the highest biomass, lipids production and lipids content (12.1 g/L, 8.25 g/L and 65%, respectively), and lipids produced under different C/N ratio conditions have potential for biodiesel production. Thus, a combination of sucrose and ammonium nitrate was optimal for the lipid accumulation in R-ZL2. The findings will lay a foundation for further improving lipids yields.

In this work, microbial lipid production from non-detoxified Eucalyptus bark hydrolysate (EBH) with oleaginous xylose-utilizing Ashbya gossypii strains was explored. The best producing strain from a set of engineered strains was identified in synthetic media mimicking the composition of the non-detoxified EBH (SM), the lipid profile was characterized, and yeast extract and corn steep liquor (CSL) were pinpointed as supplements enabling a good balance between lipid accumulation, biomass production, and autolysis by A. gossypii. The potential of the engineered A. gossypii A877 strain to produce lipids was further validated and optimized with minimally processed inhibitor-containing hydrolysate and high sugar concentration, and scaled up in a 2 L bioreactor. Lipid production from non-detoxified EBH supplemented with CSL reached a lipid titer of 1.42 g/L, paving the way for sustainable single-cell oil production within the concept of circular economy and placing lipids as an alternative by-product within microbial biorefineries.

The pH of skin is very decisive in the life of humans because it helps in enhancing infections that are related to antimicrobials. So far, the skin of humans considered is the main outdoor for several bacterial infections. The acidic Nature (pH) of the skin performs an integral physiologically part in the body and it has been identified as a regulatory component in the stratum corneum's homeostasis and skin barrier permeability. Surveys were done later illustrated that aggregation, skin barrier function& lipid production, epidermal differentiation& desquamation are basically impacted by the pH itself. Multiple epidermal pH figures have also been observed and tested in this study, all within the acidic condition however varying from pH 4.0 to 7.0, and depending on this pH, the 'natural' skin surface pH is expected to be 4.7 to 5.75 or 6. In addition, various studies are available in the latest days that focused primarily on alterations inside the pH of the stratum corneum's deeper layers including the effect of various physiological and pathological variables. Whenever the skin barrier is compromised, pH rises, resulting in a variety of ailments, including dermatitis, irritating contact dermatitis, ichthyosis, acne, and dry and ageing skin. In the current review, we will summarise many autogenous factors and exogenic factors such as skin moisture, sweat, sebum (produced by sebaceous glands), anatomic site, genetic susceptibility, age, detergents, so-called skin health maintenance products, wounds occlusive dressing could bother the pH of the skin. With that, we collected several publications in this review and explored the importance of pH surface and the key factors that influence skin's pH-related skin illness. We'll also go over how to determine the pH of the surface of the skin and also how it would affect skin and wounds. [ABSTRACT FROM AUTHOR]

As an interesting alternative microbial platform for the sustainable synthesis of oleochemical building blocks and biofuels, oleaginous yeasts are increasing in both quantity and diversity. In this study, oleaginous yeast species from northern Thailand were discovered to add to the topology. A total of 127 yeast strains were isolated from 22 forest soil samples collected from mountainous areas. They were identified by an analysis of the D1/D2 domain of the large subunit rRNA (LSU rRNA) gene sequences to be 13 species. The most frequently isolated species were Lipomyces tetrasporus and Lipomyces starkeyi. Based on the cellular lipid content determination, 78 strains of ten yeast species, and two potential new yeast that which accumulated over 20% of dry biomass, were found to be oleaginous yeast strains. Among the oleaginous species detected, Papiliotrema terrestris and Papiliotrema flavescens have never been reported as oleaginous yeast before. In addition, none of the species in the genera Piskurozyma and Hannaella were found to be oleaginous yeast. L. tetrasporus SWU-NGP 2-5 accumulated the highest lipid content of 74.26% dry biomass, whereas Lipomyces mesembrius SWU-NGP 14-6 revealed the highest lipid quantity at 5.20 ± 0.03 g L−1. The fatty acid profiles of the selected oleaginous yeasts varied depending on the strain and suitability for biodiesel production. [ABSTRACT FROM AUTHOR]

Using Palm Oil Mill Effluent (POME) as a medium for culturing oleaginous yeast is advantageous for simultaneous lipid production and waste removal. The organic compounds in POME can be utilised as a nutrient source for yeast growth. Rhodotorula toruloides yeast was cultivated in filtered and unfiltered raw POME as growth media in this study. The yeast growth, pH changes in media, lipid production and removal of chemical oxygen demand (COD) of Rhodotorula toruloides cultivated in POME were examined and compared to Rhodotorula toruloides grown in yeast peptone dextrose (YPD) control media. The COD level of filtered POME was reduced by nearly 50% after filtration. The biomass concentration of Rhodotorula toruloides in filtered POME surpassed the other media in the following order: filtered POME > YPD > unfiltered POME (152 mg/ml > 121 mg/ml > 37 mg/ml). The filtered POME was found favourable for yeast growth due to the minimal amount of colloidal particles and suspended solids. Meanwhile, the lipid production (4.51 %) in filtered POME was 4.8-fold higher than in control media. The water analysis indicated about 43% of COD reduction, signifying the ability of Rhodotorula toruloides to utilise nutrient components present in POME for growth. This study provides insightful knowledge on the utilisation of oleaginous yeast for simultaneous green waste disposal and sustainable microbial oil production. [ABSTRACT FROM AUTHOR]

Chlamydomonas reinhardtii is a model strain to explore algal lipid metabolism mechanism, and exhibits great potentials in large-scale production of lipids. Completely lacking nitrogen is an efficient strategy to trigger the lipid synthesis in microalgal cells, while it always leads to the obvious reduction in the biomass. To illustrate the optimal culture substrate carbon (C) and nitrogen (N) levels to simultaneously stimulate the growth and lipid production of C. reinhardtii, cells were cultivated under altered C and N concentrations. Results showed that replenishing 6 g/L sodium acetate (NaAc) could increase 1.50 and 1.53 times biomass and lipid productivity compared with 0 g/L NaAc treatment (the control), but total lipid content slightly decreased. Reducing 75% of basic medium (TAP) N level (0 g/L NaAc + 0.09 g/L NH4Cl treatment) could promote 21.57% total lipid content in comparison with the control (containing 0.38 g/L NH4Cl), but decrease 44.45% biomass and 34.15% lipid productivity. The result of the central composite design (CCD) experiment suggested the optimum total lipid content together with higher biomass and lipid productivity could be obtained under the condition of 4.12 g/L NaAc and 0.20 g/L NH4Cl. They reached 32.14%, 1.68 g/L and 108.21 mg/L/d, and increased by 36.77%, 93.10% and 1.75 times compared with the control, respectively. It suggests moderately increasing C supply and decreasing N levels could synchronously improve the biomass and lipid content of C. reinhardtii. [ABSTRACT FROM AUTHOR]

Toxic cyanobacterial blooms are recurrent for few decades throughout the globe, due to climate change, atmospheric warming and various anthropogenic activities with severe impacts of potential toxins on various ecosystems finally affecting the entire environment. These cyanobacteria are merely unexplored regarding their biochemical components except toxins. Variable influences and interactions of different factors including nitrogen, carbon, and availability of light are well known to crucially regulate cyanobacterial growth and metabolism. Thus, current research work is motivated for the evaluation and optimization of the effects of the aforementioned vital factors for improvement of biomass and lipid production of a freshwater, toxic strain of Anabaena circinalis. The modelling and optimization of factors such as nitrogen, light intensity and bicarbonate concentration (source of carbon) to maximize growth and lipid production were based on 20 design point experiments by Response Surface Methodology (RSM) and optimized values were further improved and validated by Particle Swarm Optimization (PSO) algorithm. The maximum optima were obtained 1.829 g L-1 and 39.64 % for biomass production and lipid content respectively from PSO optimization with two different sets of optimal values of factors. It shows 0.44 % and 2.77 % higher values of responses than that of RSM optimization. These asynchronous findings pioneered the enhanced lipid accumulation as well as the growth of a toxic cyanobacterium by optimizing interaction effects of culture conditions through various statistical and computational approaches. • Influencing factors were optimized for the improvement of biomass and lipid production. • RSM was used to optimize the system parameters and validated by PSO algorithm. • Maximum optima were obtained as 1.829 g L-1 and 39.64 % for biomass production. • Results shows that 0.44 % and 2.77 % higher values than that of RSM optimization. [ABSTRACT FROM AUTHOR]

Environmental pollution, greenhouse gas emissions, depletion of fossil fuels, and a growing population have sparked a search for new and renewable energy sources such as biodiesel. The use of waste or residues as substrates for microbial growth can favor the implementation of a biorefinery concept with reduced environmental footprint. Cyanobacteria constitute microorganisms with enhanced ability to use industrial effluents, wastewaters, forest residues for growth, and concomitant production of added-value compounds. In this study, a recently isolated cyanobacterium strain of Pseudanabaena sp. was cultivated on hydrolysates from pretreated forest biomass (silver birch and Norway spruce), and the production of biodiesel-grade lipids was assessed. Optimizing carbon source concentration and the (C/N) carbon-to-nitrogen ratio resulted in 66.45% w/w lipid content when microalgae were grown on glucose, compared to 62.95% and 63.79% w/w when grown on spruce and birch hydrolysate, respectively. Importantly, the lipid profile was suitable for the production of high-quality biodiesel. The present study demonstrates how this new cyanobacterial strain could be used as a biofactory, converting residual resources into green biofuel. [ABSTRACT FROM AUTHOR]

Aims: The synergistic bio-activity between oleaginous yeast and microalga has been recognized, which would enhance lipid production as biodiesel feedstock. Nevertheless, yeast and microalga require different conditions for optimal growth. In this study, the locally isolated oleaginous yeast Rhodotorula toruloides and microalga Chaetoceros muelleri were cocultivated to enhance biomass and lipid production. Methodology and results: The growth characteristics of both yeast and microalga monocultures were initially determined prior to optimizing the co-cultivation conditions. The biomass and lipid productivity of the co-culture were investigated and compared to their monocultures. The results showed that R. toruloides grew actively within 3 days while C. muelleri exhibited more prolonged cultivation, up to 21 days. The co-cultivation could be carried out optimally using growth media at pH 6, light intensity of 15,000 lux and yeast/microalga ratio of 1:2, yielding the highest biomass productivity determined at 0.18 g/l/day and lipid production of 17%. The lipid productivity of the co-culture increased by 42% and 75% as compared to monocultures of yeast and microalga, respectively. Furthermore, the biomass productivity was also higher than the monoculture, about 1.2-fold for the yeast and 13-fold for the microalga. Conclusion, significance and impact of study: The findings revealed that co-cultivation of yeast and microalga is a viable technique for long-term microbial oil production. [ABSTRACT FROM AUTHOR]

This paper studied the bifurcation phenomena that can occur in a continuous bioreactor for lipid-rich biomass production using Rhodococcus opacus that feeds on refinery wastewater. An unstructured model of the bioreactor was developed based on experimentally validated studies reported in the literature. The analysis of the unsteady-state model was carried out both analytically and through numerical simulations. It was shown that the inhibition effect of the biomass growth rate can lead to the occurrence of static bistability in the model. Periodic behavior was also found for some range of model parameters. The effect of model parameters on the productivity of the bioreactor was also investigated. The analysis carried out in this paper allowed for the detection of unsafe operating regions in the bioreactor which, would help in the attenuation of these operational problems in the early stage of process design. [ABSTRACT FROM AUTHOR]

Adding organic compounds to wastewater can improve the carbon/nitrogen ratio and benefit microalgae growth. We studied microalgal growth, nutrient removal and lipid accumulation of Chlorella pyrenoidosa cultured in a mixture of swine wastewater (SW) and furfural wastewater (FW). The mix ratio of SW:DFW (diluted furfural wastewater) had a significant effect on microalgae growth. As the mix ratio of SW:DFW decreased from 1:0.5 to 1:19, the maximum microalgal biomass increased, while the specific growth rate initially increased and then decreased. The efficiency of nutrient removal also depended on the mix ratio of wastewater. The highest chemical oxygen demand (COD) removal efficiency (57.30%) occurred at the mix ratio of SW:DFW = 1:3. The highest removal efficiencies of total phosphorous (TP) reached 61.93% when the mix ratio of SW:DFW was 1:9. Wastewater at the mix ratio of SW:DFW = 1:19 had a maximum lipid productivity of 49.48 mg L−1 d−1, which was 4.9 times higher than that at a mix ratio of SW:DFW = 1:0.5. These results showed that C. pyrenoidosa can be used to remove nutrients from mixed wastewater sources and simultaneously produce algal lipids. [ABSTRACT FROM AUTHOR]

AimOur aim was to identify the relationship between several surrogate insulin resistance (IR) indices based on lipid products and the development of hypertension.Materials and methodsA total of 3,281 participants aged ≥ 18 years enrolled in the China Health and Nutrition Survey from 2009 to 2015 and who were followed up for 6 years were included in the final analysis. Logistic regression was used to analyze the association between different IR indices and incident hypertension.ResultsThere were 882 (28.9%) hypertensive participants in 2015. With regard to the homeostasis model assessment of insulin resistance (HOMA-IR) based on insulin level, subjects in the highest quartile of HOMA-IR values were more likely to develop hypertension [RR = 1.58 (1.26–1.98), P < 0.001] after being adjusted by sex and age, smoke habits, alcohol consumption, community type, married status, and education years in 2009. Subjects in the highest quartile of the triglyceride-glucose index (TyG) combined with body mass index (BMI) and waist circumference (WC) had more than two times the risk of hypertension after full adjustment compared with individuals in the lowest quartile (both P < 0.001), and the trend continued when adjusted for the HOMA-IR. Compared with those in the lowest quartile of TyG-BMI values, females in the highest quartile had a higher risk of developing hypertension than males [2.82 (2.01–3.97) vs. 2.56 (1.80–3.64)] after the full adjustment, and the trend existed independent of IR. Young participants in the highest quartile of the HOMA-IR had significantly higher risks of hypertension compared with subjects in the lowest quartile [1.67 (1.31–2.14), P < 0.005], and this trend was not significant in the elderly participants.ConclusionThe results from our large-scale study elucidate the superiority of the TyG-BMI and TyG-WC compared with the HOMA-IR in the prediction of hypertension, which may be related to lipid deposition. The sex-specific predictive value is distinct for different IR indicators.

Oleaginous yeast can produce lipids while degrading phenol in wastewater treatment. In this study, a Plackett-Burman Design (PBD) was adopted to identify key factors of phenol degradation and lipid production using R toruloides 9564T. While temperature, inoculum size, and agitation were significant for both the processes (p < 0.05), pH and incubation were significant for lipid production, and phenol removal, respectively. Results from four factors (pH, temperature, inoculum size, and incubation period) central composite design (CCD) experiment were used to formulate quadratic and genetic algorithm-optimized ANN models. The reduced quadratic model for phenol degradation (R 2 : 0.993) and lipid production (R 2 : 0.958) were marginally inferior to ANN models (R 2 : 0.999, 0.982, respectively) on training sets. Multi-objective optimization with equal importance suggests phenol degradation between 106.4 and 108.76%, and lipid production of 0.864–0.903 g/L, by polynomial and ANN models. Complete phenol degradation (100%) and 3.35-fold increment (0.918 g/L) in lipid production were obtained at pH 6.07, inoculum size 14.68% v/v, at 29.5 °C in 92.17 h experimentally. [Display omitted] • PB design identified effective variables for phenol degradation and lipid synthesis. • RSM-CCD shows R2 values of 0.99 and 0.96 for phenol degradation and lipid synthesis. • RSM-CCD revealed a 3.5-fold increase in lipid synthesis under optimal conditions. • ANN-GA validate RSM-CCD data on phenol degradation and lipid synthesis. • ANN-GA found R2 values of 0.99 and 0.95 for phenol degradation and lipid synthesis. [ABSTRACT FROM AUTHOR]

Oleic acid is increasingly required in many industries, causing the indiscriminate extension of land for the cultivation of certain agricultural products to extract their oil. The current contribution aimed to cultivate Candida wangnamkhiaoensis (CW) for the production of lipids and determine the profile of fatty acids in these lipids. The lipid yield was compared in the yeast when using glucose or glycerol as the substrate, in both cases being over 24%. The main fatty acids in the oil derived from CW were oleic, palmitic, stearic, and linoleic acid. The fatty acid composition of the oil from CW was very similar to that of avocado oil and resembled that of olive oil and palm oil. The advantages of cultivating CW include its relatively high percentage of oleic acid and the balance of other fatty acids, its capacity to generate lipids in a short time (48–72 h), the controlled environment of production (versus the variability of the cultivation of agricultural products), and the relatively limited surface area required. CW shows potential as an alternative and economical source of oleic acid for the food, drug, cosmetics, lubricant, and biofuel industries, and does not require the alteration of large extensions of land.

Low biomass yield and nutrient removal efficiency are problems challenging the employment of microorganisms for wastewater remediation. Starch processing effluent (SPE) was used as a fermentation substrate to co-culture Chlorella vulgaris and Rhodotorula glutinis for biofuel feedstock production. Co-culture options were compared, and the optimal conditions were identified. The result shows that microalgae and yeast should be inoculated simultaneously at the beginning of SPE-based fermentation to achieve high biomass yield and the optimal inoculation ratio, light intensity, and temperature should be 2:1, 150 μmol/m2/s, and 25 °C, respectively. Under the optimal conditions, the lipid yield of microorganisms was 1.81 g/L and the carbon–conversion ratio reached 82.53% while lipid yield and the carbon–conversion ratio in a monoculture fell in the range of 0.79–0.81 g/L and 55.93–62.61%, respectively. Therefore, compared to the monoculture model, the co-fermentation of Chlorella vulgaris and Rhodotorula glutinis in starch processing effluent could convert nutrients to single-cell oil in a more efficient way. It should be noted that with the reduced concentration of residual organic carbon in effluent and the increased carbon–conversion ratio, co-fermentation of microalgae and yeast can be regarded as a promising and applicable strategy for starch processing effluent remediation and low-cost biofuel feedstock production.

With the aim of developing bioprocesses for waste valorization and a reduced water footprint, we optimized a two-step fermentation process that employs the oleaginous yeast Cutaneotrichosporon oleaginosus for the production of oil from liquid cheese whey permeate. For the first step, the addition of urea as a cost-effective nitrogen source allowed an increase in yeast biomass production. In the second step, a syrup from candied fruit processing, another food waste supplied as carbon feeding, triggered lipid accumulation. Consequently, yeast lipids were produced at a final concentration and productivity of 38 g/L and 0.57 g/L/h respectively, which are among the highest reported values. Through this strategy, based on the valorization of liquid food wastes (WP and mango syrup) and by recovering not only nutritional compounds but also the water necessary for yeast growth and lipid production, we addressed one of the main goals of the circular economy. In addition, we set up an accurate and fast-flow cytometer method to quantify the lipid content, avoiding the extraction step and the use of solvents. This can represent an analytical improvement to screening lipids in different yeast strains and to monitoring the process at the single-cell level. [ABSTRACT FROM AUTHOR]

The development of clean, sustainable alternative energy sources is increasingly important. One promising alternative to depleting fuel reserves is algae-based biodiesel fuel, which is both non-toxic and renewable. Despite the tremendous potential of algae-based biodiesel fuel, it has not yet been profitable because of the high cost per unit area of large cultivation. We present a novel application of Orthogonal Array Composite Designs (OACDs) to optimize lipid production of a cell-free system for algae. An OACD consists of a two-level fractional factorial design and a three-level orthogonal array. We start with an initial screening experiment based on six chemicals using an OACD with 50 runs. Based on this experiment, two chemical compounds were removed and a follow-up 25-run OACD with four chemicals was performed. Our analysis shows that only three chemicals – nitrogen, magnesium, and phosphate – are essential for lipid accumulation, and a range of optimum combinations of these three chemicals is identified. The lipid accumulation for these three chemical combinations is substantially higher in comparison to the commercial medium, which contains 16 chemicals and soil water. This leads to a reduced cost of the chemical medium and increased efficiency of biodiesel production from the algal-based cell-free system, which can be used to significantly expand the use of biodiesel as a viable alternative to fossil fuels. Copyright © 2015 John Wiley & Sons, Ltd.