Effect of synthetic and natural media on lipid production from Fusarium oxysporum

Oleaginous fungi: a promising source of biofuels and nutraceuticals with enhanced lipid production strategies

Oleaginous fungi have attracted a great deal of interest for their potency to accumulate high amounts of lipids (more than 20% of biomass dry weight) and polyunsaturated fatty acids (PUFAs), which have a variety of industrial and biological applications. Lipids of plant and animal origin are related to some restrictions and thus lead to attention towards oleaginous microorganisms as reliable substitute resources. Lipids are traditionally biosynthesized intra-cellularly and involved in the building structure of a variety of cellular compartments. In oleaginous fungi, under certain conditions of elevated carbon ratio and decreased nitrogen in the growth medium, a change in metabolic pathway occurred by switching the whole central carbon metabolism to fatty acid anabolism, which subsequently resulted in high lipid accumulation. The present review illustrates the bio-lipid structure, fatty acid classes and biosynthesis within oleaginous fungi with certain key enzymes, and the advantages of oleaginous fungi over other lipid bio-sources. Qualitative and quantitative techniques for detecting the lipid accumulation capability of oleaginous microbes including visual, and analytical (convenient and non-convenient) were debated. Factors affecting lipid production, and different approaches followed to enhance the lipid content in oleaginous yeasts and fungi, including optimization, utilization of cost-effective wastes, co-culturing, as well as metabolic and genetic engineering, were discussed. A better understanding of the oleaginous fungi regarding screening, detection, and maximization of lipid content using different strategies could help to discover new potent oleaginous isolates, exploit and recycle low-cost wastes, and improve the efficiency of bio-lipids cumulation with biotechnological significance.

Protective effects of hepatic diseases by bioactive phytochemicals in Fusarium oxysporum - A review

Lately, liver diseases were categorized as one of the most prevalent health problems globally as it causes a severe threat to mankind all over the world due to the wide range of occurrence. There are multiple factors causing hepatic disorders, such as alcohol, virus, poisons, adverse effects of drugs, poor diet, inherited conditions and obesity. Liver diseases have various types including alcoholic liver disease, non-alcoholic fatty liver disease, autoimmune hepatitis, liver cancer, hepatocellular carcinoma, liver fibrosis and hepatic inflammation. Therefore, it is imperative to find effective and efficacious agents in managing liver diseases. Fusarium oxysporum, an endophytic fungus and containing many bioactive compounds, could be served as a forked medication for enormous number and types of maladies. It was characterized by producing biochemical compounds which had rare pharmacological properties as it may be found in a limit number of other medicinal plants. The majority of the past researches related to Fusarium oxysporum recited the fungal negative field either on the pathogenic effects of the fungus on economical crops or on the fungal chemical components to know how to resist it. The present review will highlight on the bright side of Fusarium oxysporum and introduce the functional activities of its chemical compounds for treating its target diseases. The key point of illustrated studies in this article is displaying wide range of detected bioactive compounds isolated from Fusarium oxysporum and in other illustrated studies it was elucidated the therapeutical and pharmacological potency of these biologically active compounds (isolated from medicinal plants sources) against different types of liver diseases including non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and others. It was demonstrated that F. oxysporum contains unique types of isoflavones, flavonoids, phenols and another active chemical compounds, and these compounds showed recently a fabulous clinical contribution in the therapy of liver injury diseases, which opens new and unprecedented way for evaluating the maintaining efficacy of Fusarium oxysporum bioactive compounds in dealing with hepatic complications and its remedy impacting on liver diseases and injured hepatocytes through recommending implement a practical study.

Unveiling the anticancer potentiality of single cell oils produced by marine oleaginous Paradendryphiella sp. under optimized economic growth conditions

Bioprospecting about new marine oleaginous fungi that produce advantageous bioproducts in a green sustainable process is the key of blue bioeconomy. Herein, the marine Paradendryphiella sp. was utilized for single cell oils (SCOs) production economically, via central composite design, the lipid content enhanced 2.2-fold by 5.5 g/L lipid yeild on seawater-based media supplemented with molasses concentration 50 g/L, yeast extract, 2.25 g/L at initial pH value (5.3) and 8 days of static incubation. Subsequently, the fatty acid methyl esters profiles of SCOs produced on optimized media under different abiotic conditions were determined; signifying qualitative and quantitative variations. Interestingly, the psychrophilic-prolonged incubation increased the unsaturation level of fatty acids to 59.34%, while ω-6 and ω-3 contents representing 23.53% and 0.67% respectively. Remarkably, it exhibited the highest EC100 dose by 677.03 µg/mL on normal human lung fibroblast Wi-38 cells. Meanwhile, it showed the highest inhibiting proliferation potential on cancer cell lines of A549, MDA-MB 231 and HepG-2 cells by 372.37, 417.48 and 365.00 µg/mL, respectively. Besides, it elevated the oxidative stress, the expression of key apoptotic genes and suppressed the expression of key oncogenes (NF-κB, BCL2 and cyclin D); implying its promising efficacy in cancer treatment as adjuvant drug. This study denoted the lipogenesis capacity of Paradendryphiella sp. under acidic/alkaline and psychrophilic/mesophilic conditions. Hereby attaining efficient and economic process under seasonal variation with different Egyptian marine sources to fill the gap of freshwater crisis and simultaneously preserve energy.

Microbial Lipid Based Biorefinery Concepts: A Review of Status and Prospects

The use of lignocellulosic biomass as a raw material for the production of lipids has gained increasing attention, especially in recent years when the use of food in the production of biofuels has become a current technology. Thus, the competition for raw materials for both uses has brought the need to create technological alternatives to reduce this competition that could generate a reduction in the volume of food offered and a consequent commercial increase in the value of food. Furthermore, the use of microbial oils has been studied in many industrial branches, from the generation of renewable energy to the obtainment of several value-added products in the pharmaceutical and food industries. Thus, this review provides an overview of the feasibility and challenges observed in the production of microbial lipids through the use of lignocellulosic biomass in a biorefinery. Topics covered include biorefining technology, the microbial oil market, oily microorganisms, mechanisms involved in lipid-producing microbial metabolism, strain development, processes, lignocellulosic lipids, technical drawbacks, and lipid recovery.

Optimization of multiple enzymes production by fermentation using lipid-producing Bacillus sp

The present study identified the pectinase-producing bacterium isolated from the contaminated broth as Bacillus sp. on 16S rDNA sequence analysis. The bacterium illustrated water-like droplets on the colony grown on the Sabouraud dextrose agar plate. It also exhibited multi-enzymes activities, such as pectinase, polygalacturonase, xylanase, and cellulase by using various agro-wastes as low-cost substrates. The orange peel was observed to be the best substrate among the agro-wastes used for maximum multi-enzymes (pectinase, polygalacturonase, xylanase, and cellulase). However, the bacterium demonstrated its capability to produce different enzymes according to the different substrates/agro-wastes used. The Plackett–Burman design was used to determine the essential influencing factors, while the Box Behnken design response surface methodology was for optimizing cultural conditions. At their optimal conditions (40°C incubation temperature, 24 h of incubation period, 1% w/v orange peel, and 2% v/v inoculum volume), the bacterium exhibited the maximum pectinase (9.49 ± 1.25 U/ml) and xylanase (16.27 ± 0.52 U/ml) activities. Furthermore, the study explored the ability of the bacterium to produce bacterial lipids and observed about 25% bacterial lipid content on a dry weight basis. Therefore, the bacterium is a good candidate for producing important multi-enzymes and subsequent agro-waste degradation controlling the environment, and facilitating waste management. Also, the bacterium can be a potential feedstock in producing renewable biofuel.

An Approach for Incorporating Glycerol as a Co-Substrate into Unconcentrated Sugarcane Bagasse Hydrolysate for Improved Lipid Production in Rhodotorula glutinis

Sugarcane bagasse is a potential raw material for microbial lipid production by oleaginous yeasts. Due to the limited sugar concentrations in bagasse hydrolysate, increasing carbon the concentration is necessary in order to improve lipid production. We aimed to increase carbon concentration by incorporating glycerol as a co-substrate into unconcentrated bagasse hydrolysate in the cultivation of Rhodotorula glutinis TISTR 5159. Cultivation in hydrolysate without nitrogen supplementation (C/N = 42) resulted in 60.31% lipid accumulation with 11.45 ± 0.75 g/L biomass. Nitrogen source supplementation increased biomass to 26.29 ± 2.05 g/L without losing lipid accumulation at a C/N of 25. Yeast extract improved lipid production in the hydrolysate due to high growth without altering the lipid content of the cells. Mixing glycerol up to 10% v/v into the unconcentrated hydrolysate improved biomass and lipid production. A further increase in glycerol concentrations drastically decreased growth and lipid accumulation by the yeast. By maintaining C/N at 27 using yeast extract as the sole nitrogen source, hydrolysate mixed with 10% v/v glycerol resulted in the highest lipid yield, at 19.57 ± 0.53 g/L with 50.55% lipid content, which was a 2.8-fold increase compared to using the hydrolysate alone. In addition, yeast extracts were superior for promoting growth and lipid production compared to inorganic nitrogen sources.

Advances in production of high-value lipids by oleaginous yeasts

The global market for high-value fatty acids production, mainly omega-3/6, hydroxy fatty-acids, waxes and their derivatives, has seen strong development in the last decade. The reason for this growth was the increasing utilization of these lipids as significant ingredients for cosmetics, food and the oleochemical industries. The large demand for these compounds resulted in a greater scientific interest in research focused on alternative sources of oil production - among which microorganisms attracted the most attention. Microbial oil production offers the possibility to engineer the pathways and store lipids enriched with the desired fatty acids. Moreover, costly chemical steps are avoided and direct commercial use of these fatty acids is available. Among all microorganisms, the oleaginous yeasts have become the most promising hosts for lipid production - their efficient lipogenesis, ability to use various (often highly affordable) carbon sources, feasible large-scale cultivations and wide range of available genetic engineering tools turns them into powerful micro-factories. This review is an in-depth description of the recent developments in the engineering of the lipid biosynthetic pathway with oleaginous yeasts. The different classes of valuable lipid compounds with their derivatives are described and their importance for human health and industry is presented. The emphasis is also placed on the optimization of culture conditions in order to improve the yield and titer of these valuable compounds. Furthermore, the important economic aspects of the current microbial oil production are discussed.

Physiological Traits of Dihomo-γ-Linolenic Acid Production of the Engineered Aspergillus oryzae by Comparing Mathematical Models

Dihomo-γ-linolenic acid (DGLA; C20:3 n-6) is expected to dominate the functional ingredients market for its role in anti-inflammation and anti-proliferation. The DGLA production by the engineered strain of Aspergillus oryzae with overexpressing Pythium Δ6-desaturase and Δ6-elongase genes was investigated by manipulating the nutrient and fermentation regimes. Of the nitrogen sources tested, the maximum biomass and DGLA titers were obtained in the cultures using NaNO3 grown at pH 6.0. For establishing economically feasible process of DGLA production, the cost-effective medium was developed by using cassava starch hydrolysate (CSH) and NaNO3 as carbon and nitrogen sources, respectively. The supplementation with 1% (v/v) mother liquor (ML) into the CSH medium promoted the specific yield of DGLA production (Y DGLA / X ) comparable with the culture grown in the defined NaNO3 medium, and the DGLA proportion was over 22% in total fatty acid (TFA). Besides, the GLA was also generated at a similar proportion (about 25% in TFA). The mathematical models of the cultures grown in the defined NaNO3 and CSH/ML media were generated, describing that the lipid and DGLA were growth-associated metabolites corresponding to the relevant kinetic parameters of fermentations. The controlled mode of submerged fermentation of the engineered strain was explored for governing the PUFA biosynthesis and lipid-accumulating process in relation to the biomass production. This study provides an informative perspective in the n-6 fatty acid production through physiological manipulation, thus leading to a prospect in viable production of the DGLA-enriched oil by the engineered strain.

An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries

Microorganisms are known to be natural oil producers in their cellular compartments. Microorganisms that accumulate more than 20% w/w of lipids on a cell dry weight basis are considered as oleaginous microorganisms. These are capable of synthesizing vast majority of fatty acids from short hydrocarbonated chain (C6) to long hydrocarbonated chain (C36), which may be saturated (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA), depending on the presence and number of double bonds in hydrocarbonated chains. Depending on the fatty acid profile, the oils obtained from oleaginous microorganisms are utilized as feedstock for either biodiesel production or as nutraceuticals. Mainly microalgae, bacteria, and yeasts are involved in the production of biodiesel, whereas thraustochytrids, fungi, and some of the microalgae are well known to be producers of very long-chain PUFA (omega-3 fatty acids). In this review article, the type of oleaginous microorganisms and their expertise in the field of biodiesel or omega-3 fatty acids, advances in metabolic engineering tools for enhanced lipid accumulation, upstream and downstream processing of lipids, including purification of biodiesel and concentration of omega-3 fatty acids are reviewed.

Optimization of cultural conditions for lipid accumulation by Aspergillus wentii Ras101 and its transesterification to biodiesel: application of response surface methodology

The present study is aimed to maximize biodiesel production by using the fungal strain Aspergillus wentii Ras101 as a feedstock. Response surface methodology was used to relate the interaction between some nutritional and environmental factors affecting the lipid productivity by A. wentii Ras101. By applying LINGO optimization program, the maximum lipid production of 40% dry biomass of this fungal isolate has been attained in a fermentation medium composed of 50 g/l glucose, 1 g/l nitrates, 1.5 g/l phosphorous, and 0.5 g/l NaCl. This medium was adjusted at pH of 6, and incubated at 28 °C for 7 days. The values of correlation errors between the experimental and estimated values are less than 1%; this proves that the proposed correlation could be used effectively for estimating the fungal lipid production. Consequently, the effects of time and temperature on the amount of biodiesel produced in the extraction and transesterification one-step process have been investigated. The maximum biodiesel production of 28% dry biomass (80% lipid) has been achieved in the transesterification process at 70 °C for 30 min. Additionally, it is found that the combination of glucose, nitrogen and phosphorous contents has a positive influence on lipid production in the fungal biomass. The density, kinematic viscosity, water content and calorific value of the produced biodiesel were 800 kg/m³, 2.8 mm²/s, 66 ppm and 10122 kcal/kg, respectively that matched well with biodiesel and fossil standard specifications.

Heterotrophic cultivation of Auxenochlorella protothecoides using forest biomass as a feedstock for sustainable biodiesel production

BACKGROUND

The aim of this work was to establish a process for the heterotrophic growth of green microalgae using forest biomass hydrolysates. To provide a carbon source for the growth of the green microalgae, two forest biomasses (Norway spruce and silver birch) were pretreated with a hybrid organosolv-steam explosion method, resulting in inhibitor-free pretreated solids with a high cellulose content of 77.9% w/w (birch) and 72% w/w (spruce). Pretreated solids were hydrolyzed using commercial cellulolytic enzymes to produce hydrolysate for the culture of algae.

RESULTS

The heterotrophic growth of A. protothecoides was assessed using synthetic medium with glucose as carbon source, where the effect of sugar concentration and the carbon-to-nitrogen ratio were optimized, resulting in accumulation of lipids at 5.42 ± 0.32 g/L (64.52 ± 0.53% lipid content) after 5 days of culture on glucose at 20 g/L. The use of birch and spruce hydrolysates was favorable for the growth and lipid accumulation of the algae, resulting in lipid production of 5.65 ± 0.21 g/L (66 ± 0.33% lipid content) and 5.28 ± 0.17 g/L (63.08 ± 0.71% lipid content) when grown on birch and spruce, respectively, after only 120 h of cultivation.

CONCLUSIONS

To the best of our knowledge, this is the first report of using organosolv pretreated wood biomass hydrolysates for the growth and lipid production of microalgae in the literature. The pretreatment process used in this study provided high saccharification of biomass without the presence of inhibitors. Moreover, the lipid profile of this microalga showed similar contents to vegetable oils which improve the biodiesel properties.