Hydrolysate Medium Research Articles

Two-Stage Fermentation of Lipomyces starkeyi for Production of Microbial Lipids and Biodiesel.

The high operating cost is currently a limitation to industrialize microbial lipids production by the yeast Lipomyces starkeyi. To explore economic fermentation technology, the two-stage fermentation of Lipomyces starkeyi using yeast extract peptone dextrose (YPD) medium, orange peel (OP) hydrolysate medium, and their mixed medium were investigated for seven days by monitoring OD600 values, pH values, cell growth status, C/N ratios, total carbon concentration, total nitrogen concentration, residual sugar concentration, lipid content, lipid titer, and fatty acids profiles of lipids. The results showed that two-stage fermentation with YPD and 50% YPD + 50% OP medium contributed to lipid accumulation, leading to larger internal lipid droplets in the yeast cells. However, the cells in pure OP hydrolysate grew abnormally, showing skinny and angular shapes. Compared to the one-stage fermentation, the two-stage fermentation enhanced lipid contents by 18.5%, 27.1%, and 21.4% in the flasks with YPD medium, OP medium, and 50%YPD + 50%OP medium, and enhanced the lipid titer by 77.8%, 13.6%, and 63.0%, respectively. The microbial lipids obtained from both one-stage and two-stage fermentation showed no significant difference in fatty acid compositions, which were mainly dominated by palmitic acid (33.36–38.43%) and oleic acid (46.6–48.12%). Hence, a mixture of commercial medium and lignocellulosic biomass hydrolysate could be a promising option to balance the operating cost and lipid production.

Maximizing the simultaneous production of lipids and carotenoids by Rhodosporidium toruloides from wheat straw hydrolysate and perspectives for large-scale implementation

This study aimed to select fermentation conditions able to simultaneously maximize the production of lipids and carotenoids by oleaginous yeast cultivated in wheat straw hydrolysate. An evolved strain of Rhodosporidium toruloides with improved tolerance to toxic compounds present in hydrolysate medium was used. Experiments were performed in order to investigate the effect of the temperature and inoculum load on the production of lipids and carotenoids by R. toruloides. Results revealed that the accumulation of both products can be simultaneously maximized when performing the fermentation at 17 °C and using 3.5 g/L of inoculum. This maximum simultaneous production opens up new perspectives for the establishment of a feasible and more sustainable large-scale process for the production of lipids and carotenoids. Even corresponding to only 1% of the cell mass, due to the high market value, carotenoids would account for more than 90% of the total income of the industrial plant.

Isolation and Identification of a High-Yield Ethyl Caproate-Producing Yeast From Daqu and Optimization of Its Fermentation.

Baijiu is an important fermented product in China. A yeast named YX3307 that is capable of producing a large amount of ethyl caproate (EC) was isolated from Daqu, a crude fermentation starter for Baijiu. This yeast was identified as Clavispora lusitaniae on the basis of its morphological properties, physiological and biochemical characteristics, and 26S rDNA sequence. Single-factor experiments were conducted to obtain the optimum fermentation conditions for EC production by YX3307. The highest EC yield (62.0 mg/L) from YX3307 was obtained with the following culture conditions: inoculum size 7.5% (v/v), seed cell age 30 h, sorghum hydrolysate medium (SHM) with a sugar content of 10 Brix and an initial pH of 6.0; incubation at 28°C with shaking at 180 rpm for 32 h; addition of 10% (v/v) anhydrous ethanol and 0.04% (v/v) caproic acid at 32 and 40 h, respectively, static culture at 20°C until 72 h. YX3307 synthesized more EC than ethyl acetate, ethyl lactate, ethyl butyrate, and ethyl octanoate. An intracellular enzyme or cell membrane enzyme was responsible for EC synthesis. YX3307 can produce many flavor compounds that are important for high-quality Baijiu. Thus, it has potential applications in improving the flavor and quality of Baijiu.

Further engineering of R. toruloides for the production of terpenes from lignocellulosic biomass

BackgroundMitigation of climate change requires that new routes for the production of fuels and chemicals be as oil-independent as possible. The microbial conversion of lignocellulosic feedstocks into terpene-based biofuels and bioproducts represents one such route. This work builds upon previous demonstrations that the single-celled carotenogenic basidiomycete, Rhodosporidium toruloides, is a promising host for the production of terpenes from lignocellulosic hydrolysates.ResultsThis study focuses on the optimization of production of the monoterpene 1,8-cineole and the sesquiterpene α-bisabolene in R. toruloides. The α-bisabolene titer attained in R. toruloides was found to be proportional to the copy number of the bisabolene synthase (BIS) expression cassette, which in turn influenced the expression level of several native mevalonate pathway genes. The addition of more copies of BIS under a stronger promoter resulted in production of α-bisabolene at 2.2 g/L from lignocellulosic hydrolysate in a 2-L fermenter. Production of 1,8-cineole was found to be limited by availability of the precursor geranylgeranyl pyrophosphate (GPP) and expression of an appropriate GPP synthase increased the monoterpene titer fourfold to 143 mg/L at bench scale. Targeted mevalonate pathway metabolite analysis suggested that 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR), mevalonate kinase (MK) and phosphomevalonate kinase (PMK) may be pathway bottlenecks are were therefore selected as targets for overexpression. Expression of HMGR, MK, and PMK orthologs and growth in an optimized lignocellulosic hydrolysate medium increased the 1,8-cineole titer an additional tenfold to 1.4 g/L. Expression of the same mevalonate pathway genes did not have as large an impact on α-bisabolene production, although the final titer was higher at 2.6 g/L. Furthermore, mevalonate pathway intermediates accumulated in the mevalonate-engineered strains, suggesting room for further improvement.ConclusionsThis work brings R. toruloides closer to being able to make industrially relevant quantities of terpene from lignocellulosic biomass.

Adaptive laboratory evolution of Rhodosporidium toruloides to inhibitors derived from lignocellulosic biomass and genetic variations behind evolution

Using lignocellulosic biomass hydrolysate for the production of microbial lipids and carotenoids is still a challenge due to the poor tolerance of oleaginous yeasts to the inhibitors generated during biomass pretreatment. In this study, a strategy of adaptive laboratory evolution in hydrolysate-based medium was developed to improve the tolerance of Rhodosporidium toruloides to inhibitors present in biomass hydrolysate. The evolved strains presented better performance to grow in hydrolysate medium, with a significant reduction in their lag phases, and improved ability to accumulate lipids and produce carotenoids when compared to the wild-type starting strain. In the best cases, the lag phase was reduced by 72 h and resulted in lipid accumulation of 27.89 ± 0.80% (dry cell weight) and carotenoid production of 14.09 ± 0.12 mg/g (dry cell weight). Whole genome sequencing analysis indicated that the wild-type strain naturally contained tolerance-related genes, which provided a background that allowed the strain to evolve in biomass-derived inhibitors.

Preparation of γ-polyglutamic acid from enzymatic hydrolysate of poplar sawdust

The treatment of forestry waste has always been an environmental problem. In this study, poplar sawdust was used to produce γ-polyglutamic acid (γ-PGA). Poplar sawdust was treated with acid and then hydrolyzed with cellulose. The enzymatic hydrolysate was used to produce γ-PGA. Through single factor and orthogonal experiments, the optimum enzymatic conditions were determined as follows: solid-liquid ratio 1:5, enzyme amount 22 FPU/g, pH 5.0 and 53 min. Under the enzymatic hydrolysate medium, the γ-PGA yield reached 30.87 ± 0.44 g/L, which was 5.11% higher than that in glucose medium (29.37 ± 0.43 g/L). In addition, the amount of glucose added to the medium was reduced, which realized the comprehensive utilization of various sugars in sawdust enzymatic hydrolysate. Although the fermentation time was prolonged by 4 h, this study provided a new and feasible method for the industrial utilization of forestry waste and the clean production of γ-PGA.

Bacterial cellulose production from ethylenediamine pretreated Caragana korshinskii Kom

In this study, three different pretreatment technologies (hydrothermal, NaOH, and ethylenediamine (EDA) pretreatment) were investigated to improve the efficiency of the enzymatic conversion of Caragana korshinskii Kom. (CKK). The effects of the pretreatment conditions on the composition, structure, and enzymatic hydrolysis of CKK were evaluated. The results indicated that EDA pretreatment was more effective in promoting CKK digestibility than the other pretreatments. EDA exhibited a good delignification ability (up to 72.8%) and a strong de-crystallization effect (up to 29.9%) compared to hydrothermal and NaOH pretreatment. The best result for the cellulose enzymatic conversion (88.0%) was obtained at 210 °C for 40 min with 30 mL EDA. Using of the EDA-pretreated CKK as a substrate for bacterial cellulose (BC) production indicated that a lower nutrient level in the enzymatic hydrolysate medium could be a key factor that impedes the fermentation performance of Gluconacetobacter xylinus. The addition of extra nutrients promoted BC production efficiency, and under optimized conditions, the BC yield was 4.6 g/L.

Use of Filled Bioplastics in Construction

Polymers and associated composite materials play an increasingly prominent role among structural materials. The relevance of the use of bioplastics as an alternative to synthetic polymers increases year by year. In this regard, the paper describes the production of a ligno-filled polymer material based on polyhydroxyalkanoates to be used in the production of building materials. The studies allowed us to produce the material from wood hydrolyzates. The highest yield of reducing substances in course of pine sawdust hydrolysis with 4% sulfurous acid occurred at 170°C. To obtain a biopolymer in liquid wood hydrolyzate medium, the Cupriavidus necator strain was used, which after 50 hours of cultivation gave a biopolymer yield of up to 15 g/l. The studies of the strength characteristics of the composite based on the obtained bioplastic and dried solid wood hydrolysates allowed us to produce a balanced composition for subsequent use in construction.

Integrated biorefinery process for production of sophorolipids from corn straw

Sophorolipids (SLs) are biosurfactants composed by a dimeric carbohydrate sophorose linked to a hydroxyl group of a fatty acid, and they have a great potential for commercial using in different industrial sectors due to their superior environmental compatibility combined with excellent functional properties. In this study, hydrolysate of corn straw cellulose was used as a hydrophilic carbon substrate to produce sophorolipids with Starmerella bombicola ATCC 22214. The two-step method was employed for detoxification of corn straw hydrolysate, and the process of detoxification was optimized. The yield of sophorolipids obtained using the detoxified hydrolysate medium was 2.07 fold higher than that obtained using undetoxified hydrolysate. In addition, the optimal conditions for the production of sophorolipids were as follows: the hydrophobic carbon source was 6 % (w/v) oleic acid, the nitrogen source was 0.45 % (w/v) ammonium nitrate, the metal ions was 0.075 % (w/v) Fe2+ ions, and the pH of the fermentation broth was 3.0. The yield of lactonic sophorolipid and total sophorolipid following 7 days of fermentation reached a maximum of 6.16 g/l and 27.45 g/l, respectively. These results demonstrate the biorefinery of corn straw to produce SLs is a kind of utilization method with industrialization potential, which can realize the high-value comprehensive utilization of corn straw.

Biosynthesis of α-Pinene by Genetically Engineered Yarrowia lipolytica from Low-Cost Renewable Feedstocks.

α-Pinene, an important biologically active natural monoterpene, has been widely used in fragrances, medicines, and fine chemicals, especially, in high-density renewable fuels such as jet fuel. The development of an α-pinene production platform in a highly modifiable microbe from renewable substitute feedstocks could lead to a green, economical avenue, and sustainable biotechnological process for the biosynthesis of α-pinene. Here, we report engineering of an orthogonal biosynthetic pathway for efficient production of α-pinene in oleaginous yeast Yarrowia lipolytica that resulted in an α-pinene titer of 19.6 mg/L when using glucose as the sole carbon source, a significant 218-fold improvement than the initial titer. In addition, the potential of using waste cooking oil and lignocellulosic hydrolysate as carbon sources for α-pinene production from the engineered Y. lipolytica strains was analyzed. The results indicated that α-pinene titers of 33.8 and 36.1 mg/L were successfully obtained in waste cooking oil and lignocellulosic hydrolysate medium, thereby representing the highest titer reported to date in yeast. To our knowledge, this is also the first report related to microbial production of α-pinene from waste cooking oil and lignocellulosic hydrolysate.

Sequential fed batch extractive fermentation for enhanced bioethanol production using recycled Spathaspora passalidarum and mixed sugar composition

The simultaneous ethanol production and removal during sequential cell recycle fed batch fermentation provides a complementary route to produce this biofuel from sugar mixtures, which may greatly improve yields and productivity from lignocellulosic hydrolysates. Spathaspora passalidarum is a wild-type strain able to naturally convert glucose, fructose, xylose and arabinose into ethanol. Therefore, the present work has focused on 2G bioethanol production by S. passalidarum aiming at the consumption of all sugars released after pre-treatment and enzymatic hydrolysis of sugarcane bagasse in a single fermentation step. The fermentation strategy with sequential cell recycle, fed-batch mode and ethanol removal in situ was performed on a hemicellulosic hydrolysate medium supplemented with molasses. This strategy gave improved fermentation performance and enabled the co-fermention of all sugars under microaerobic conditions. The maximum ethanol yield and productivity was 0.482 g.g−1 and 9.5 g·L-1·h−1, respectively, showing a process efficiency of 94.3%. The selective ethanol removal enables the operation of the bioreactor at low levels of ethanol (20–30 g·L-1), even with high sugar concentration inputs, accelerating the fermentation performance and avoiding inhibitory effects on yeast metabolism. Applying the cell recycle strategy, S. passalidarum was able to increase its robustness, as shown by a 10-fold increase in ethanol productivity, and it was also able to tolerate a high acetic acid concentration (4.5 g·L-1) during long-term fermentations. These results demonstrate that the bioprocess strategy has a strong potential to improve bioethanol production of rich mixed sugar from lignocellulosic hydrolysates in a single fermentation step.

Process scale-up of an efficient acid-catalyzed steam pretreatment of rice straw for xylitol production by C. Tropicalis MTCC 6192

The present study focuses on operational parameters for the efficient acid catalyzed rice straw pretreatment process for xylitol production. 75.77 % xylose yield was attained when the 24 h presoaked rice straw (≤10 mm or ≤ 15 mm) in 1.5 % (v/v) H2SO4 was pretreated in the same reactor at 121 °C for 30 min. Neutralization with barium hydroxide produced insoluble salt and noticeably reduced HMF and furfurals. Xylitol yield of 0.6 g/g of xylose, was achieved by fermenting rice straw hydrolysate medium with C. tropicalis MTCC 6192. This two-step process of production of xylitol from xylose rich hydrolysate is much simpler and produced minimal inhibitors including organic acids such as acetic acid. This process is modified for upscaling at optimized parameters and will simultaneously minimize the pollution problem caused by rice straw and is also promising for commercial scale.

Lipid Accumulation by Xylose Metabolism Engineered Mucor circinelloides Strains on Corn Straw Hydrolysate.

Previously, we presented a novel approach for increasing the consumption of xylose and the lipid yield by overexpressing the genes coding for xylose isomerase (XI) and xylulokinase (XK) in Mucor circinelloides. In the present study, an in-depth analysis of lipid accumulation by xylose metabolism engineered M. circinelloides strains (namely Mc-XI and Mc-XK) using corn straw hydrolysate was to be explored. The results showed that the fatty acid contents of the engineered M. circinelloides strains were, respectively, increased by 19.8% (in Mc-XI) and 22.3% (in Mc-XK) when compared with the control strain, even though a slightly decreased biomass in these engineered strains was detected. Moreover, the xylose uptake rates of engineered strains in the corn straw hydrolysate were improved significantly by 71.5% (in Mc-XI) and 68.8% (in Mc-XK), respectively, when compared with the control strain. Maybe the increased utilization of xylose led to an increase in lipid synthesis. When the recombinant M. circinelloides strains were cultured in corn straw hydrolysate medium with the carbon-to-nitrogen ratio (C/N ratio) of 50 and initial pH of 6.0, at 30 °C and 500 rpm for 144 h, a total biomass of 12.6-12.9 g/L with a lipid content of 17.2-17.7% (corresponding to a lipid yield of 2.17-2.28 g/L) was achieved. Our study provides a foundation for the further application of the engineered M. circinelloides strains to produce lipid from lignocelluloses.

Primary Amebic Meningoencephalitis Related to Groundwater in Costa Rica: Diagnostic Confirmation of Three Cases and Environmental Investigation

During the first trimester of 2020, the Ministry of Health of Costa Rica reported the first three cases of primary amebic meningoencephalitis (PAM). In two cases, laboratory personnel of the hospitals preliminarily identified amoeboid forms in cerebrospinal fluid (CSF) samples. For the molecular confirmation of species, CSF samples were sent to our laboratory. We carried out microscopic analyses and exflagellation assays. Besides, samples were cultured in 2% casein hydrolysate medium and in non-nutrient agar plates supplemented with Escherichia coli. Finally, PCR and sequencing were employed for the molecular diagnosis and species identification. In all cases, the presence of Naegleria fowleri was confirmed. An environmental investigation to identify the possible infection sources was also performed. Water samples from hot springs and groundwater from an artisan well were collected and after filtration and culture in non-nutrient agar plates supplemented with E. coli, thermotolerance and exflagellation assays were carried out. For the positive samples, PCR and sequencing were performed, confirming the presence of N. fowleri in several water samples. The report of these cases and the possible association with hot springs has had a significant impact on the population and health authorities of Costa Rica.

Structural-chemical characterization and potential of sisal bagasse for the production of polyols of industrial interest

Sisal is a potential raw material for the production of bioproducts because it has high contents of cellulose and hemicellulose that generate fermentable sugars and can produce compounds of value for industrial use. The present study evaluates the structural composition of sisal bagasse to use it in the production of arabitol and xylitol. Sisal bagasse was characterized by determination of the moisture, pH, ash, soluble solids, extractives, alpha cellulose, holocellulose, hemicellulose and lignin. Electron microscopy and infrared and X-ray diffraction analyses were also performed. The cell growth of the yeast Debaryomyces hansenii in synthetic media was tested to determine the best conditions for the fermentation in the sisal bagasse hydrolysate. The results showed high amounts of hemicellulose (22.91%) in sisal bagasse biomass when compared to sugarcane and the conversion of hemicellulose, breaking into pentoses in the hydrolysed liquor from the sisal bagasse, was efficient (liquor rich in pentoses). These evidences were obtained through analytical determinations such as SEM and physical analyses of infrared and X-ray diffraction; in addition, the results showed that D. hansenii gave excellent arabitol production (1.14 g L−1) values in the sisal bagasse hydrolysate medium, thus demonstrating the importance of the biomass for obtaining bioproducts.

One-pot process for lactic acid production from wheat straw by an adapted Bacillus coagulans and identification of genes related to hydrolysate-tolerance

In this study, Bacillus coagulans CC17A with highly tolerant to hydrolysate was obtained through adaptive evolution. After 63 generations, the strain CC17A was stably in 45% (v/v) hydrolysate media and could digest multiple inhibitors in the hydrolysate. Based on its promising features, a one-pot process was developed to produce lactic acid (LA) from wheat straw. After dilute acid pretreatment of wheat straw, simultaneous saccharification and co-fermentation was conducted using CC17A without any solid-liquid separation and pre-detoxification. Total 35.50 g LA was produced from 80 g raw substrate and the production yield was as high as 70.9% of theoretical. To elucidate the tolerance mechanism, transcriptomic profiling of CC17A was studied. The highly up-regulated oxidoreductases and phenolic acid decarboxylase are considered to be involved with the inhibitors-tolerance of B. coagulans CC17A.

Medium design from corncob hydrolyzate for pigment production by Talaromyces atroroseus GH2: Kinetics modeling and pigments characterization

The genus Talaromyces has gained attention due to its ability to produce pigments with potential industrial applications in different areas. Prosperous application of fungal pigments has challenges to overcome, like developing a cost-effective bioprocess. Using agroindustrial wastes could provide inexpensive substrates and it contributes to maximize sustainability. Therefore, this study evaluated the feasibility of using corncob as a low-cost substrate for pigment production by Talaromyces atroroseus GH2. An acid hydrolysis treatment was used to release sugars from corncob. Corncob liquors with enough xylose concentration (>20 g/L) were investigated as fermentation media with and without the addition of nutrients. Process kinetic modeling was applied and pigments produced in corncob and control media were characterized. The diluted hydrolyzate without nutrient supplementation showed a pigment production (16.17±0.37 OD500nm) comparable to the control medium (17.26±0.41 OD500nm). Talaromyces atroroseus GH2 was able to co-utilize xylose and glucose in the corncob-based medium. However, growth kinetics patterns differed in both media. In the hydrolyzate medium, biomass growth presented an extended lag phase, which requires reduction for future process optimization. Finally, characterized pigments differed among evaluated media, but the pigments produced by Talaromyces atroroseus GH2 were mostly Monascus’ pigments homologous like monascorubrin and rubropunctamine. Talaromyces atroroseus GH2 ability to produce pigments using corncob hydrolyzate makes it a pigment-producing strain for an economically competitive large fermentation scale.

Rosmarinic acid, a new raw material, doubled monoclonal antibody titer in cell culture manufacturing

This report contains a case study of late phase cell culture process development where the titer was increased, final drug substance quality was maintained, and consistent manufacturing was demonstrated for production of an IgG4 monoclonal antibody. After high-throughput screening, it was found that rosmarinic acid (RA), a polyphenolic flavonoid antioxidant, increased titer by approximately 100% in comparison to either the same late phase process using chemically defined media without RA or the early phase process optimized using hydrolysate media. In a side-by-side comparison, RA increased the titer from 1.1 to 3.1 (normalized values) at 5-L scale and from 1.7 to 3.1 at 500-L scale. A comprehensive study to enable the introduction of RA, a new raw material, into a manufacturing facility was conducted. Specifically, the RA addition protocol was simplified by including it in dry powder medium, a cost evaluation was performed to show that the cost increase from RA inclusion was minimal (approximately 4% of total medium cost), and RA clearance during downstream processing was demonstrated with > 99% of RA removed in the Protein A purification step alone. A preliminary investigation into the mechanism of RA titer improvement indicates that the addition of RA leads to less generation of reactive oxygen species and lower caspase 3 expression, likely leading to the cell growth and titer increase.

Enzymatic hydrolysis of orange bagasse and effect of filtration on lactic acid fermentation

Along with the general trend of reducing waste in the agro-industrial sector, new methods are sought to utilize side or waste products. With this purpose, we examined the utilization of orange bagasse (OB) for Ca-lactate production via enzymatic hydrolysis and fermentation. The hydrolysis of OB was carried in both dried and fresh forms with cellulolytic and pectinolytic enzymes to obtain a reasonable amount of fermentable sugars for further lactic acid fermentation. A novel industrial approach was studied to increase the hydrolysis yield by reusing the former hydrolysate media. Meanwhile, lactic acid fermentation was performed with optimal OB hydrolysate by Lactobacillus delbrueckii subsp. bulgaricus OZZ4 and Lactobacillus plantarum OZH8. One of the main problems in OB utilization via fermentation was the inhibition observed on microorganisms. It was found that either by drying of the biomass prior to enzymatic hydrolysis or by filtration of the hydrolysate prepared with fresh biomass could be done in order to overcome the inhibitory effects. After treatments, lactic acid with yields around 0.95 g/g and levels of 45 g/L was produced with the fermentation of OB hydrolysate.

Utilization of the acid hydrolysate of defatted Chlorella biomass as a sole fermentation substrate for the production of biosurfactant from Bacillus subtilis C9

Although algal biofuels have been promoted as a carbon-neutral alternative to fossil fuels, several economic and technological barriers challenge the much-anticipated success of algae as a commercial bio-feedstock. In particular, utilizing only a lipid portion of harvested algal biomass limits possible monetary returns from algal biomass within which non-lipid compounds generally comprise a major proportion. Previous studies thus demonstrated the production of ethanol from defatted algal biomass to improve overall economic outlook of the nascent algae industry; however, it is also possible to utilize residual algal biomass as a fermentation substrate for bacterial strains producing high value alternative products. Therefore, the goal of this study was to compare the yield of biosurfactant from B. subtilis C9 in conventional culture medium and the acid hydrolysate of defatted Chlorella biomass (DCB). Although increasing the concentration of acid catalyst from 0 N to 1.0 N was expected to proportionally enhance the effectiveness of dilute acid hydrolysis, the results indicated that DCB hydrolysates treated under different acid conditions at 121 °C for 15 min exhibited the highest yield of fermentable monosaccharides when treated with 0.25 N HCl. Subsequently, the fermentation of B. subtilis C9 was performed in both Luria-Bertani (LB) and DCB hydrolysate medium after adjusting salinity and monosaccharide concentration to identical levels; a significantly greater yield of biosurfactant was observed in the culture grown with DCB hydrolysate medium, while the presence of magnesium and manganese co-factors in DCB hydrolysate contributed to a greater biosurfactant yield. Collectively, these results suggest that the valorization of defatted algal biomass could be also accomplished by incorporating biosurfactant fermentation into algal biorefinery processes and call for further process optimization efforts that consider factors associated with the operation of industrial algal biorefineries.