Improvement of lipid production from an oil-producing filamentous fungus, Penicillium brevicompactum NRC 829, through central composite statistical design

Application of microbial resources in biorefineries: Current trend and future prospects

The recent growing interest in sustainable and alternative sources of energy and bio-based products has driven the paradigm shift to an integrated model termed "biorefinery." Biorefinery framework implements the concepts of novel eco-technologies and eco-efficient processes for the sustainable production of energy and value-added biomolecules. The utilization of microbial resources for the production of various value-added products has been documented in the literatures. However, the appointment of these microbial resources in integrated resource management requires a better understanding of their status. The main of aim of this review is to provide an overview on the defined positioning and overall contribution of the microbial resources, i.e., algae, fungi and bacteria, for various bioprocesses and generation of multiple products from a single biorefinery. By utilizing waste material as a feedstock, biofuels can be generated by microalgae while sequestering environmental carbon and producing value added compounds as by-products. In parallel, fungal biorefineries are prolific producers of lignocellulose degrading enzymes along with pharmaceutically important novel products. Conversely, bacterial biorefineries emerge as a preferred platform for the transformation of standard cells into proficient bio-factories, developing chassis and turbo cells for enhanced target compound production. This comprehensive review is poised to offer an intricate exploration of the current trends, obstacles, and prospective pathways of microbial biorefineries, for the development of future biorefineries.

Influence of Borassus flabellifer Endocarps Hydrolysate on Fungal Biomass and Fatty Acids Production by the Marine Fungus Aspergillus sp

Polyunsaturated Fatty Acids (PUFAs) are important nutrients for human health. We aimed to evaluate the efficiency of marine water fungus Aspergillus sp. (Accession no: MZ505709) for lipid biosynthesis. The Yeast Extract Glucose (YEG) medium was supplemented with different concentration of Borassus flabellifer Endocarps Hydrolysate (BFEH; 1-5%) to evaluate the fungal biomass and its lipid accumulation. The combination of glucose and BFEH as carbon source increased the fresh weight (25.43 ± 0.33 g/L), dry weight (21.39 ± 0.77 g/L) and lipid yield (3.14 ± 0.09 g/L) of fungal biomass. The lipid content of dried fungal biomass has shown 91.08 ± 5.07 mg cod liver oil equivalents/g and 125.98 ± 5.96 mg groundnut oil equivalents/g biomass. GC-MS and NMR spectrometry analysis revealed the compounds involved in fatty acid metabolism and lipid signaling pathways along with the presence of linolenic acid. Interestingly, fungus grown in BFEH enriched medium has recorded the maximum amount of lipids with major fatty acid derivatives. Increase in the growth rate of Artemia franciscana was observed, when the extracted fungal lipid was supplemented as a food supplement. Therefore, this study suggests that marine fungal lipid may serve as potential natural compound as nutraceuticals and aquafeeds.

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.

Effects of Nitrogen and Phosphorus Limitation on Fatty Acid Contents in Aspergillus oryzae

Aspergillus oryzae, commonly known as koji mold, has been widely used for the large-scale production of food products (sake, makgeolli, and soy sauce) and can accumulate a high level of lipids. In the present study, we showed the dynamic changes in A. oryzae mycelium growth and conidia formation under nitrogen and phosphorus nutrient stress. The fatty acid profile of A. oryzae was determined and the content of unsaturated fatty acid was found increased under nitrogen and phosphorus limitation. Oleic acid (C18:1), linoleic acid (C18:2), and γ-linolenic acid (C18:3) production were increased on five nitrogen and phosphorus limitation media, especially on nitrogen deep limitation and phosphorus limitation group, showing a 1. 2-, 1. 6-, and 2.4-fold increment, respectively, compared with the control. Transcriptomic analysis showed the expression profile of genes related to nitrogen metabolism, citrate cycle, and linoleic acid synthesis, resulting in the accumulation of unsaturated fatty acid. qRT-PCR results further confirmed the reliability and availability of the differentially expressed genes obtained from the transcriptome analysis. Our study provides a global transcriptome characterization of the nitrogen and phosphorus nutrient stress adaptation process in A. oryzae. It also revealed that the molecular mechanisms of A. oryzae respond to nitrogen and phosphorus stress. Our finding facilitates the construction of industrial strains with a nutrient-limited tolerance.

Enhancement of lipid productivity from a promising oleaginous fungus

Oleaginous fungi have recently gained increasing attention among different microorganisms due to their ability for lipid production for the preparation of biofuel. In the present study, a locally isolated fungus E45, identified genetically as Aspergillus sp. strain EM2018, was found to produce 25.2% of the total lipids content of its dry cell weight (DCW). Optimization of culture conditions was performed and lipid accumula­tion increased by about 2.4 fold (from 25.2% to 60.1% of DCW) when the fungus was grown for seven days in the potato dextrose (50 g/L) liquid medium at pH 5.0, incubation temperature at 30 ºC and inoculum size of 2 × 106 spore/mL. Supplementation of the medium with yeast extract and NaNO3 at a concentration of 0.05% as organic and inorganic nitrogen sources, respectively, increased lipid production (53.3% lipid/dry biomass). Gas chromatography analysis of fungal lipids revealed the presence of saturated (mainly palmitic acid C16:0 (33%) and lignoceric acid C24:0 (15%)) and unsaturated fatty acids in different proportions (mainly linoleic acid C18:2 (24.4%), oleica cid C18:1 (14%) and arachidonic C20:4 (7.4%). These findings suggest this new oleaginous fungus as a promising feedstock for various industrial applications and for the preparation of biodiesel.

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.