Development of a Circular Oriented Bioprocess for Microbial Oil Production Using Diversified Mixed Confectionery Side-Streams

Diversified mixed confectionery waste streams were utilized in a two-stage bioprocess to formulate a nutrient-rich fermentation media for microbial oil production. Solid-state fermentation was conducted for the production of crude enzyme consortia to be subsequently applied in hydrolytic reactions to break down starch, disaccharides, and proteins into monosaccharides, amino acids, and peptides. Crude hydrolysates were evaluated in bioconversion processes using the red yeast Rhodosporidium toruloides DSM 4444 both in batch and fed-batch mode. Under nitrogen-limiting conditions, during fed-batch cultures, the concentration of microbial lipids reached 16.6–17 g·L−1 with the intracellular content being more than 40% (w/w) in both hydrolysates applied. R. toruloides was able to metabolize mixed carbon sources without catabolite repression. The fatty acid profile of the produced lipids was altered based on the substrate employed in the bioconversion process. Microbial lipids were rich in polyunsaturated fatty acids, with oleic acid being the major fatty acid (61.7%, w/w). This study showed that mixed food side-streams could be valorized for the production of microbial oil with high unsaturation degree, pointing towards the potential to produce tailor-made lipids for specific food applications. Likewise, the proposed process conforms unequivocally to the principles of the circular economy, as the entire quantity of confectionery by-products are implemented to generate added-value compounds that will find applications in the same original industry, thus closing the loop.

Download Full-text

Heterologous Expression of Two Malate Transporters From an Oleaginous Fungus Mucor circinelloides Improved the Lipid Accumulation in Mucor lusitanicus

Frontiers in Microbiology ◽

10.3389/fmicb.2021.774825 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiuwen Wang ◽

Hassan Mohamed ◽

Yonghong Bao ◽

Chen Wu ◽

Wenyue Shi ◽

...

Keyword(s):

Fatty Acid ◽

Lipid Accumulation ◽

Carbon Sources ◽

Reducing Power ◽

Acid Synthesis ◽

Mucor Circinelloides ◽

Microbial Lipids ◽

Intracellular Lipid ◽

Engineering Technology ◽

Oleaginous Fungus

The fungus, Mucor lusitanicus, is of great interest for microbial lipids, because of its ability to accumulate intracellular lipid using various carbon sources. The biosynthesis of fatty acid requires the reducing power NADPH, and acetyl-CoA, which is produced by the cleavage of citrate in cytosol. In this study, we employed different strategies to increase lipid accumulation in the low lipid-producing fungi via metabolic engineering technology. Hence, we constructed the engineered strain of M. lusitanicus CBS 277.49 by using malate transporter (mt) and 2-oxoglutarate: malate antiporter (sodit) from M. circinelloides WJ11. In comparison with the control strain, the lipid content of the overexpressed strains of mt and sodit genes were increased by 24.6 and 33.8%, respectively. These results showed that mt and sodit can affect the distribution of malate in mitochondria and cytosol, provide the substrates for the synthesis of citrate in the mitochondria, and accelerate the transfer of citrate from mitochondria to cytosol, which could play a significant regulatory role in fatty acid synthesis leading to lipids over accumulation.

Download Full-text

Exploring low-cost carbon sources for microbial lipids production by fed-batch cultivation of Cryptococcus albidus

Biotechnology and Bioprocess Engineering ◽

10.1007/s12257-010-0370-y ◽

2011 ◽

Vol 16 (3) ◽

pp. 482-487 ◽

Cited By ~ 63

Author(s):

Qiang Fei ◽

Ho Nam Chang ◽

Longan Shang ◽

Jin-dal-rae Choi

Keyword(s):

Low Cost ◽

Carbon Sources ◽

Batch Cultivation ◽

Microbial Lipids ◽

Cryptococcus Albidus ◽

Fed Batch ◽

Lipids Production ◽

Fed Batch Cultivation

Download Full-text

Optimization of Oil Production from Cassava Pulp and Sugarcane Bagasse using Oleaginous Yeast

Oriental Journal Of Chemistry ◽

10.13005/ojc/350222 ◽

2019 ◽

Vol 35 (2) ◽

pp. 668-677 ◽

Cited By ~ 2

Author(s):

Phakamas Rachamontree ◽

Malinee Sriariyanun ◽

Surapun Tepaamorndech ◽

Issaraporn Somboonwatthanakul

Keyword(s):

Fatty Acid ◽

Sugarcane Bagasse ◽

Agricultural Waste ◽

Value Added ◽

Oil Production ◽

Biodiesel Production ◽

Oil Yield ◽

Microbial Oil ◽

Crude Lipid ◽

Cassava Pulp

Microbial oil is one of alternative sources for biofuel and value-added chemical production in biorefining process of lignocellulosic biomass. The bottleneck of this process is the low conversion rate of lignocellulose biomass to the target product. This research aims to optimize microbial oil production as raw material for biorefining process from agricultural waste by using Plackett–Burman (PB) design and Response Surface Methodology (RSM). Acid-hydrolysates of cassava pulp and sugarcane bagasse were converted to bio-oil by fermentation activities of two oleaginous yeasts, designated as MSU2 and Ka28. The fermentation parameters were screened by PB design to identify their impacts on oil yield, and the condition of each parameter was optimized by RSM to maximized oil yield. The predicted optimal condition obtained from RSM provided the highest lipid yield at 34.56 and 21.85% from hydrolysates of cassava pulp and sugarcane bagasse, respectively. Then, fatty acid compositions in oil were analyzed by GCMS, and our results demonstrated that palmitic acid and oleic acid were the major constituents at 72.95 and 195.01 mg/g-crude lipid, respectively. These fatty acid distribution profiles were suitable for application in biodiesel production and suggested the utilization of agricultural waste in biorefining process.

Download Full-text

Rhodotorula toruloides Single Cell Oil Production Using Eucalyptus urograndis Hemicellulose Hydrolysate as a Carbon Source

Energies ◽

10.3390/en13040795 ◽

2020 ◽

Vol 13 (4) ◽

pp. 795 ◽

Cited By ~ 4

Author(s):

Helberth Júnnior Santos Lopes ◽

Nemailla Bonturi ◽

Everson Alves Miranda

Keyword(s):

Carbon Source ◽

Lipid Production ◽

Carbon Sources ◽

Oil Production ◽

Research Area ◽

Microbial Oil ◽

Hemicellulose Hydrolysate ◽

Initial Ph ◽

Different Temperatures ◽

Active Research

Microbial oil is a potential substitute for vegetable oils in the biodiesel industry. Efforts to obtain cheap carbon sources for the cultivation of lipid-producing microorganisms comprise an active research area. This work aimed to extract the hemicellulose fraction from Eucalyptus uograndis and to use its hydrolysate as a carbon source for Rhodotorula toruloides (an oleaginous yeast) cultivation for microbial oil production. Hemicellulose hydrothermal extractions were performed at different temperatures, times, and ratios of solid to liquid (S/L). Temperature and time showed a stronger effect on the solubilization of hemicellulose. Hemicellulose extraction at 155 °C, 195 min, and an S/L ratio of 1/2 resulted in a hydrolysate with a xylose content of 37.0 g/l. R. toruloides cultivation in this hydrolysate showed that initial pH had a strong influence on cell growth. At an initial pH of 6.2, cells grew to 6.0 g/l of biomass with a lipid content of 50%. Therefore, we believe that E. urograndis hemicellulose hydrolysate could be a potential substrate for R. toruloides for lipid production based on the biorefinery concept.

Download Full-text

Volatile Fatty Acids (VFAs) Generated by Anaerobic Digestion Serve as Feedstock for Freshwater and Marine Oleaginous Microorganisms to Produce Biodiesel and Added-Value Compounds

Frontiers in Microbiology ◽

10.3389/fmicb.2021.614612 ◽

2021 ◽

Vol 12 ◽

Author(s):

Alok Patel ◽

Amir Mahboubi ◽

Ilona Sárvári Horváth ◽

Mohammad J. Taherzadeh ◽

Ulrika Rova ◽

...

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Food Waste ◽

Environmental Sustainability ◽

Volatile Fatty Acids ◽

Oil Production ◽

Added Value ◽

Microbial Oil ◽

Omega 3 ◽

Freshwater Microalgae

Given an increasing focus on environmental sustainability, microbial oils have been suggested as an alternative to petroleum-based products. However, microbial oil production relies on the use of costly sugar-based feedstocks. Substrate limitation, elevated costs, and risk of contamination have sparked the search for alternatives to sugar-based platforms. Volatile fatty acids are generated during anaerobic digestion of organic waste and are considered a promising substrate for microbial oil production. In the present study, two freshwater and one marine microalga along with two thraustochytrids were evaluated for their potential to produce lipids when cultivated on volatile fatty acids generated from food waste via anaerobic digestion using a membrane bioreactor. Freshwater microalgae Auxenochlorella protothecoides and Chlorella sorokiniana synthesized lipids rich in palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (C18:2). This composition corresponds to that of soybean and jatropha oils, which are used as biodiesel feedstock. Production of added-value polyunsaturated fatty acids (PUFA) mainly omega-3 fatty acids was examined in three different marine strains: Aurantiochytrium sp. T66, Schizochytrium limacinum SR21, and Crypthecodinium cohnii. Only Aurantiochytrium sp. T66 seemed promising, generating 43.19% docosahexaenoic acid (DHA) and 13.56% docosapentaenoic acid (DPA) in total lipids. In summary, we show that A. protothecoides, C. sorokiniana, and Aurantiochytrium sp. T66 can be used for microbial oil production from food waste material.

Download Full-text

Rhodococcus as Biofactories for Microbial Oil Production

Molecules ◽

10.3390/molecules26164871 ◽

2021 ◽

Vol 26 (16) ◽

pp. 4871

Author(s):

Héctor M. Alvarez ◽

Martín A. Hernández ◽

Mariana P. Lanfranconi ◽

Roxana A. Silva ◽

María S. Villalba

Keyword(s):

Molecular Mechanisms ◽

Carbon Sources ◽

Oil Production ◽

Dry Weight ◽

Industrial Wastes ◽

Natural Environments ◽

Microbial Oil ◽

Qualitative And Quantitative ◽

Physiological Properties ◽

Wide Range

Bacteria belonging to the Rhodococcus genus are frequent components of microbial communities in diverse natural environments. Some rhodococcal species exhibit the outstanding ability to produce significant amounts of triacylglycerols (TAG) (>20% of cellular dry weight) in the presence of an excess of the carbon source and limitation of the nitrogen source. For this reason, they can be considered as oleaginous microorganisms. As occurs as well in eukaryotic single-cell oil (SCO) producers, these bacteria possess specific physiological properties and molecular mechanisms that differentiate them from other microorganisms unable to synthesize TAG. In this review, we summarized several of the well-characterized molecular mechanisms that enable oleaginous rhodococci to produce significant amounts of SCO. Furthermore, we highlighted the ability of these microorganisms to degrade a wide range of carbon sources coupled to lipogenesis. The qualitative and quantitative oil production by rhodococci from diverse industrial wastes has also been included. Finally, we summarized the genetic and metabolic approaches applied to oleaginous rhodococci to improve SCO production. This review provides a comprehensive and integrating vision on the potential of oleaginous rhodococci to be considered as microbial biofactories for microbial oil production.

Download Full-text