Submerged Liquid Fermentation Research Articles

Complex nitrogen sources from agro-industrial byproducts: impact on production, multi-stress tolerance, virulence, and quality of Beauveria bassiana blastospores.

Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.

Oil-in-water (O/W) nanoemulsion loaded with biotransformation product containing limonene and α-terpineol stabilized with Tween®20: Formation and physicochemical stability along with time

Aroma chemicals are essential in the food industry as they are added to numerous food products to enhance sensory experience. However, preserving the shelf-life and maintaining the physicochemical stability of these additives is a challenging task for food processors. Encapsulation techniques can help overcome these challenges by facilitating incorporation, increasing loading capacity and enabling controlled release of flavor oils. This study specifically focused on encapsulating a biotransformation product comprising a blend of alpha-terpineol (α-TOH), limonene (LIM), and soybean oil, obtained through bioconversion of limonene in a submerged liquid fermentation media using Sphingobium sp. as a biocatalyst. By using Tween®20 as a surfactant, an oil-in-water nanoemulsion system was used as encapsulation strategy to extend the shelf life of these sensitive flavor oils. Subsequently, the nanoemulsified samples were subjected to varying temperatures (5 °C, 25 °C, and 50 °C) for up to 600 days. The physical stability of the samples we assessed by measuring mean droplet diameter and turbidity, while chemical stability was analyzed using gas chromatography (GC). Findings revealed that physical stability was maintained for up to 600 days at 5 °C and 25 °C. Conversely, the nanoemulsion broke down on the 120th day when exposed to 50 °C. Furthermore, it was found that the chemical stability was temperature-dependent, with losses of LIM and α-TOH increasing as the storage temperature rose. In conclusion, this study emphasizes the critical role of encapsulation techniques in prolonging the shelf life of sensitive compounds such as aroma chemicals.

Combination of Solid State and Submerged Fermentation Strategies to Produce a New Jellyfish-Based Food.

This study describes the set-up and optimization of a fermentation strategy applied to a composite raw material containing jellyfish biomass as the principal ingredient. New fermented food was developed by combining fresh jellyfish Rhizostoma pulmo and the sequential solid-state submerged liquid fermentation method used in Asian countries for processing a high-salt-containing raw material. Aspergillus oryzae was used to drive the first fermentation, conducted in solid-state conditions, of a jellyfish-based product, here named Jelly paste. The second fermentation was performed by inoculating the Jelly paste with different selected bacteria and yeasts, leading to a final product named fermented Jellyfish paste. For the first time, a set of safety parameters necessary for monitoring and describing a jellyfish-based fermented food was established. The new fermented products obtained by the use of Debaryomyces hansenii BC T3-23 yeast strain and the Bacillus amyloliquefaciens MS3 bacterial strain revealed desirable nutritional traits in terms of protein, lipids and total phenolic content, as well as valuable total antioxidant activity. The obtained final products also showed a complex enzyme profile rich in amylase, protease and lipase activities, thus making them characterized by unique composite sensory odor descriptors (umami, smoked, dried fruit, spices).

Production of Purpureocillium lilacinum and Pochonia chlamydosporia by Submerged Liquid Fermentation and Bioactivity against Tetranychus urticae and Heterodera glycines through Seed Inoculation.

Pochoniachlamydosporia and Purpureocillium lilacinum are fungal bioagents used for the sustainable management of plant parasitic nematodes. However, their production through submerged liquid fermentation and their use in seed treatment have been underexplored. Therefore, our goal was to assess the effect of different liquid media on the growth of 40 isolates of P. lilacinum and two of P. chlamydosporia. The most promising isolates tested were assessed for plant growth promotion and the control of the two-spotted spider mite (Tetranychus urticae) and the soybean cyst nematode (Heterodera glycines). Most isolates produced > 108 blastospores mL−1 and some isolates produced more than 104 microsclerotia mL−1. Microsclerotia of selected isolates were used to inoculate common bean (Phaseolus vulgaris L.) seeds in greenhouse trials. All fungal isolates reduced the T. urticae fecundity in inoculated plants through seed treatment, while P. chlamydosporia ESALQ5406 and P. lilacinum ESALQ2593 decreased cyst nematode population. Purpureocillium lilacinum was more frequently detected in soil, whereas P. chlamydosporia colonized all plant parts. Pochonia chlamydosporia ESALQ5406 improved the root development of bean plants. These findings demonstrate the possibility of producing submerged propagules of P. chlamydosporia and P. lilacinum by liquid culture, and greenhouse trials support the applicability of fungal microsclerotia in seed treatment to control P. vulgaris pests.

Clonostachys rosea: Production by Submerged Culture and Bioactivity Against Sclerotinia sclerotiorum and Bemisia tabaci.

Among the prospective biocontrol agents, the saprophytic filamentous fungus Clonostachys rosea is an excellent necrotrophic mycoparasite of numerous plant pathogenic fungi. However, its commercial development has been hampered by mass production difficulties during solid-state fermentation. Conversely, the submerged liquid fermentation shortens the cultivation time while increasing yields of fungal propagules. However, this method has been overlooked for C. rosea. In this work, we investigated the impact of liquid pre-culture inoculum on the spore production by the two-stage fermentation process using rice grains in comparison to the traditional solid-state fermentation. In parallel, we studied the submerged cultivation of C. rosea by manipulating carbon-to-nitrogen (C:N) ratio and nitrogen source, with the further optimization of spore production in a benchtop bioreactor. Additional bioassays included assessing the bioactivity of water-dispersible microgranules (that contained a submerged conidia) against the whitefly (Bemisia tabaci biotype B) and Sclerotinia sclerotiorum (causal agent of the white mold). Our results showed a maximum concentration of 1.1 × 109 conidia/g-dry-matter after 7 days of cultivation by two-stage fermentation process. The liquid fermentation yielded 1.4 × 109 submerged conidia/ml after 7 days using a medium with a 50:1 C:N ratio, and it also induced the production of microsclerotia (MS) up to 1.35 × 104/ml within 6 days with 10:1 C:N ratio; both media were supplemented with dextrose monohydrate and soybean meal. The fermentation batches carried out in a benchtop bioreactor with medium 50:1 C:N ratio and amended with soybean meal rendered a production peak on the fourth day, corresponding to 1.11 × 109 conidia/ml and 4.35 × 108 colony forming units (CFU)/ml. Following air-drying, the conidia production from air-dried microgranules of C. rosea biomass was estimated at 3.4 × 1010 conidia/g of formulated product upon re-hydration for 7 days. Both submerged conidia and MS of C. rosea inhibited 100% germination of S. sclerotiorum sclerotia by direct parasitism. The air-dried submerged conidia exhibited a suppressive activity on sclerotia (88% mycoparasitism) and early whitefly nymphs (76.2% mortality) that rendered LC50 values of 3.2 × 104 CFU/g soil and 1.5 × 107 CFU/ml, respectively. Therefore, the submerged liquid culture of C. rosea may offer a feasible and cost-effective method for its large-scale production, alleviating critical constraints to their commercial use while providing an additional tool for management of B. tabaci and S. sclerotiorum.

Efficient biomass-endopolysaccharide production from an identified wild-Serbian Ganoderma applanatum strain BGS6Ap mycelium in a controlled submerged fermentation

A rare wild-Serbian Ganoderma applanatum strain BGS6Ap (GASB) was morphologically identified based on its basidiocarp with brownish-red cap and woody stipe. Molecularly, GASB DNA was extracted, sequenced (651 bp) and subjected to phylogenetic analysis with evolutionary distance (Knuc). A plasmid Editor (ApE) software was used to verify the sequence and GASB was found to be 99% similarity to the commercial G. applanatum (GA) ATCC44053. The production of GASB's biomass and endopolysaccharide (ENS) in different temperature was screened at 20 °C, 25 °C and 30 °C via one-factor-at-a-time (OFAAT) scheme in a submerged liquid fermentation (SLF). Lower temperature was chosen due to GASB's natural habitat, which belongs to temperate continental climates with the influence of air currents from the Carpathians and the Mediterranean. Using the OFAAT data, the SLF was further optimised using response surface methodology (RSM) to generate biomass-ENS based on temperature (20°C–30 °C), agitation rate (100–200 rpm), glucose concentration (10 g/L–50 g/L) and initial pH (4–6). The highest production of biomass (17.51 g/L) and ENS (3.47 g/L) was generated using optimal conditions of 25 °C, 150 rpm, 10 g/L of glucose and pH 6. To study the structural composition, ENS confirmed spectral linkages in FTIR (2925 cm−1, 1623 cm−1, 1073 cm−1, 890 cm−1) and NMR (δ 4.30, 4.80, 5.20 ppm) as endo-β-D-glucan. This approach could serve as a blueprint for novel mycelial biomass and endo-β-D-glucan production of GASB which can be further studied on different temperate basidiomycetes.

The growth of marine fungi on seaweed polysaccharides produces cerato-platanin and hydrophobin self-assembling proteins

The marine fungi Paradendryphiela salina and Talaromyces pinophilus degrade and assimilate complex substrates from plants and seaweed. Additionally, these fungi secrete surface-active proteins, identified as cerato-platanins and hydrophobins. These hydrophobic proteins have the ability to self-assemble forming amyloid-like aggregates and play an essential role in the growth and development of the filamentous fungi. It is the first time that one cerato-platanin (CP) is identified and isolated from P. salina (PsCP) and two Class I hydrophobins (HFBs) from T. pinophilus (TpHYD1 and TpHYD2). Furthermore, it is possible to extract cerato-platanins and hydrophobins using marine fungi that can feed on seaweed biomass, and through a submerged liquid fermentation process. The propensity to aggregate of these proteins has been analyzed using different techniques such as Thioflavin T fluorescence assay, Fourier-transform Infrared Spectroscopy, and Atomic Force Microscopy. Here, we show that the formation of aggregates of PsCP and TpHYD, was influenced by the carbon source from seaweed. This study highlighted the potential of these self-assembling proteins generated from a fermentation process with marine fungi and with promising properties such as conformational plasticity with extensive applications in biotechnology, pharmacy, nanotechnology, and biomedicine.

Mycoprotein and hydrophobin like protein produced from marine fungi Paradendryphiella salina in submerged fermentation with green seaweed Ulva spp.

The production of new sources of protein with low environmental impact will guarantee the future of food security. Fungi are gaining importance as a promising source of food protein (mycoprotein) and also have the ability to produce surface-active proteins. This is the first time that the growing of Paradendryphiella salina (marine fungus) on Ulva spp. (green algae) through the submerged liquid fermentation for the production of mycoprotein (from mycelium) and hydrophobin like proteins (from culture broth) is reported. The nutritional composition of mycoprotein was investigated, obtaining a yield of 561.3 g of mycoprotein from 1 kg of dry algae, a good concentration of total protein (48.2 g/100 g), and a considerable concentration of total amino acids (21 g/100 g). The characterization of surface-active protein displays consistent behaviors with the class II hydrophobin. This study proves that sustainable production of mycoproteins and surface-active proteins can be developed growing a marine fungal strain, contributing to shed light on the potentiality of an integrated method that promotes the circular economy.

Production and statistical optimization of Paromomycin by Streptomyces rimosus NRRL 2455 in solid state fermentation

BackgroundParomomycin is a 2-deoxystreptamine aminocyclitol aminoglycoside antibiotic with broad spectrum activity against Gram-negative, Gram-positive bacteria and many protozoa. This study introduces a strategy for paromomycin production through solid-state fermentation using Streptomyces rimosus subsp. paromomycinus NRRL 2455. Solid state fermentation has gained enormous attention in the development of several products because of their numerous advantages over submerged liquid fermentation. After selecting the best solid substrate, a time course study of paromomycin production was carried out followed by optimization of environmental conditions using response surface methodology. Paromomycin yields obtained using this technique were also compared to those obtained using submerged liquid fermentation.ResultsUpon screening of 6 different substrates, maximum paromomycin concentration (0.51 mg/g initial dry solids) was obtained with the cost-effective agro-industrial byproduct, corn bran, impregnated with aminoglycoside production media. Optimization of environmental conditions using D-optimal design yielded a 4.3-fold enhancement in paromomycin concentration reaching 2.21 mg/g initial dry solids at a pH of 8.5, inoculum size of 5% v/w and a temperature of 30 °C.ConclusionCompared to submerged liquid fermentation, solid state fermentation resulted in comparable paromomycin concentrations, cost reduction of raw materials, less energy consumption and waste water discharge, which have major implications in industrial fermentation. Therefore, solid state fermentation is a promising alternative to submerged liquid fermentation for paromomycin production. To the best of our knowledge, this is the first report on the optimized paromomycin production through solid state fermentation process.

Isolation, Identification, and Optimization of γ-Aminobutyric Acid (GABA)-Producing Bacillus cereus Strain KBC from a Commercial Soy Sauce moromi in Submerged-Liquid Fermentation

A new high γ-aminobutyric acid (GABA) producing strain of Bacillus cereus was successfully isolated from soy sauce moromi. This B. cereus strain named KBC shared similar morphological characteristics (Gram-positive, rod-shaped) with the reference B. cereus. 16S rRNA sequence of B. cereus KBC was found to be 99% similar with B. cereus strain OPWW1 under phylogenetic tree analysis. B. cereus KBC cultivated in unoptimized conditions using De Man, Rogosa, Sharpe (MRS) broth was capable of producing 523.74 mg L−1 of GABA within five days of the cultivation period. By using response surface methodology (RSM), pH level, monosodium glutamate (MSG) concentration and temperature were optimized for a high concentration of GABA production. The pH level significantly influenced the GABA production by B. cereus KBC with p-value = 0.0023. GABA production by B. cereus KBC under the optimized condition of pH 7, MSG concentration of 5 g L−1 and temperature of 40 °C resulted in GABA production of 3393.02 mg L−1, which is 6.37-fold higher than under unoptimized conditions. Overall, this study has shown that B. cereus KBC isolated from soy sauce moromi is capable of producing a high concentration of GABA together with the optimal fermentation conditions that have been statistically analysed using RSM.

Optimisation of biomass and lipid production of a tropical thraustochytrid Aurantiochytrium sp. UMACC-T023 in submerged-liquid fermentation for large-scale biodiesel production

Abstract A tropical thraustochytrid, Aurantiochytrium sp. UMACC-T023, was optimised for high biomass and lipid production in submerged-liquid fermentation (SLF). Biomass and lipid production were optimised based on glucose, polypeptone, and yeast extract concentration using response surface methodology (RSM). In RSM, the applied central composite design (CCD) showed that the optimisation model was significant for all variables studied. Yeast extract and polypeptone were associated with significant effects in UMACC-T023 biomass production with p

A comparative study of production of hydrophobin like proteins (HYD-LPs) in submerged liquid and solid state fermentation from white rot fungus Pleurotus ostreatus

Hydrophobins are small, surface-active, cysteine-rich proteins produced by filamentous fungi. They are able to assemble spontaneously into amphipathic monolayers at hydrophobic-hydrophilic interfaces. They have a specific property of producing stable foam. Hydrophobins isolated from edible mushrooms like Pleurotus ostreatus can be used industrially for various purposes like food foams, biosurfactants, biosensors, flavor stabilizers, pharmaceutical formulations, drug delivery systems and many more. In consideration with industrial importance of the protein, the objective of this research work was to improve yield of the process. In this study Pleurotus ostreatus was grown in submerged liquid fermentation (SLF) using Yeast maltose and glucose (YMG) medium supplemented with 100 mg/L of Tryptophan and also grown in solid state fermentation (SSF) on agro-industrial waste oil cakes of coconut and sesame obtained from local market. Moisture content of SSF process was maintained at 75%. Class I Hydrophobin like proteins (HYD-LPs) were purified using Trifluroacetic acid (TFA). Sesame oil cake gave higher yield of HYD-LPs (3.85 mg/g of biomass) as compared to yield of HYD-LPs isolated from YMG submerged liquid medium (1.86 mg/g of biomass). Production in SSF was 2 fold higher than SLF. This huge difference in yields of hydrophobins underlines the suitability of solid substrate fermentation process along with addition of oil cakes to improve the yields.

Efficient biomass-exopolysaccharide production from an identified wild-Serbian Ganoderma lucidum strain BGF4A1 mycelium in a controlled submerged fermentation

Abstract A rare wild-Serbian Ganoderma applanatum strain BGS6Ap (GASB) was morphologically identified based on its basidiocarp with brownish-red cap and woody stipe. Molecularly, GASB DNA was extracted, sequenced (651 bp) and subjected to phylogenetic analysis with evolutionary distance (Knuc). A plasmid Editor (ApE) software was used to verify the sequence and GASB was found to be 99% similarity to the commercial G. applanatum (GA) ATCC44053. The production of GASB's biomass and endopolysaccharide (ENS) in different temperature was screened at 20 °C, 25 °C and 30 °C via one-factor-at-a-time (OFAAT) scheme in a submerged liquid fermentation (SLF). Lower temperature was chosen due to GASB's natural habitat, which belongs to temperate continental climates with the influence of air currents from the Carpathians and the Mediterranean. Using the OFAAT data, the SLF was further optimised using response surface methodology (RSM) to generate biomass-ENS based on temperature (20°C–30 °C), agitation rate (100–200 rpm), glucose concentration (10 g/L–50 g/L) and initial pH (4–6). The highest production of biomass (17.51 g/L) and ENS (3.47 g/L) was generated using optimal conditions of 25 °C, 150 rpm, 10 g/L of glucose and pH 6. To study the structural composition, ENS confirmed spectral linkages in FTIR (2925 cm−1, 1623 cm−1, 1073 cm−1, 890 cm−1) and NMR ( δ 4.30, 4.80, 5.20 ppm) as endo-β-D-glucan. This approach could serve as a blueprint for novel mycelial biomass and endo-β-D-glucan production of GASB which can be further studied on different temperate basidiomycetes.

Solid State Fermentation: Substrates Uses and Applications in Biomass and Metabolites Production - A Review

Solid-state fermentation (SSF) is the growth of microorganisms without free flowing liquid phase. The history of SSF is very well known to those in the fields of food processing and pharmaceuticals as it is widely applied to the production of several organic acids, flavourings compounds, enzymes and other microbial metabolites of human importance. SSF has been recently considered as the most cheapest and more environmentally friendly relative to submerged liquid fermentation (SLF) in the production of value added industrial based products such as enzymes, bio fuels and the likes. The comparison of SSF and liquid State Fermentation (LSF) has been summarized in a tabular form. The main microorganisms that occupied a pivotal position in achieving absolute SSF processes have been highlighted. A typical bioreactor has been addressed within the concept of SSF. The applications of the process in various economic sectors such as industrial fermentation, agro food industry and environmental control have been reported. Biomass measurement formula is shown, as well as environmental factors, both essential for studying and optimising solid substrate fermentations. SSF is advantageous and appropriate for production of many value added products like enzymes, antibiotics, and organic acids. This technique not only decreases the cost of the process but also makes product cheaper for consumers. This review aimed at gathering the disperse literature on the current state of art on SSF as it concerns biomass and metabolites formation.

Vital parameters for high gamma-aminobutyric acid (GABA) production by an industrial soy sauce koji Aspergillus oryzae NSK in submerged-liquid fermentation.

In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji Aspergillus oryzae strain NSK (AOSNSK). AOSNSK generated maximum GABA at 30°C (194mg/L) and initial pH 5 (231mg/L), thus was able to utilize sucrose (327mg/L of GABA) for carbon source. Sucrose at 100g/L, improved GABA production at 646mg/L. Single nitrogen sources failed to improve GABA production, however a combination of yeast extract (YE) and glutamic acid (GA) improved GABA at 646.78mg/L. Carbon-to-nitrogen ratio (C8:N3) produced the highest cell (24.01g/L) and GABA at a minimal time of 216h. The key parameters of 30°C, initial pH 5, 100g/L of sucrose, combination YE and GA, and C8:N3 generated the highest GABA (3278.31mg/L) in a koji fermentation. AOSNSK promisingly showed for the development of a new GABA-rich soy sauce.

Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology.

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p < 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p < 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum.

Biomanufacturing: history and perspective.

Biomanufacturing is a type of manufacturing that utilizes biological systems (e.g., living microorganisms, resting cells, animal cells, plant cells, tissues, enzymes, or in vitro synthetic (enzymatic) systems) to produce commercially important biomoleculesfor use inthe agricultural, food, material, energy, and pharmaceutical industries. History of biomanufacturing could be classified into the three revolutions in terms of respective product types (mainly), production platforms, and research technologies. Biomanufacturing 1.0 focuses on the production of primary metabolites (e.g., butanol, acetone, ethanol, citric acid) by using mono-culture fermentation; biomanufacturing 2.0 focuses on the production of secondary metabolites (e.g., penicillin, streptomycin) by using a dedicated mutant and aerobic submerged liquid fermentation; and biomanufacturing 3.0 focuses on the production of large-size biomolecules-proteins and enzymes (e.g., erythropoietin, insulin, growth hormone, amylase, DNA polymerase) by using recombinant DNA technology and advanced cell culture. Biomanufacturing 4.0 could focus on new products, for example, human tissues or cells made by regenerative medicine, artificial starch made by in vitro synthetic biosystems, isobutanol fermented by metabolic engineering, and synthetic biology-driven microorganisms, as well as exiting products produced by far better approaches. Biomanufacturing 4.0 would help address some of the most important challenges of humankind, such as food security, energy security and sustainability, water crisis, climate change, health issues, and conflict related to the energy, food, and water nexus.

Improved ganoderic acids production in Ganoderma lucidum by wood decaying components

Ganoderma lucidum is a legendary Traditional Chinese Medicine (TCM) over a few thousands of years and one kind of its major active components are Ganoderic acids (GAs). GAs are largely produced in the mushroom primordium and fruiting body but much less in mycelium stage. However, little is known on the underlying regulatory mechanism. As a saprophytic fungus, G. lucidum solely obtains nutrients by wood decaying. Wood in general contains sophisticated chemical components with diverse structural units. To explore a strategy that extensively leads to GAs induction in the submerged liquid fermentation, all chemical components that might be possibly from the wood decaying were tested individually as GAs inducers. It was found that GAs production increased 85.96% by 1.5% microcrystalline cellulose (MCC) and 63.90% by 0.5% D-galactose. The transcription level of a few rate-limiting or chemically diverting enzymes responsible for GAs biosynthesis was greatly induced by MCC and D-galactose. The concentration and time-course titration study indicated that these two chemicals might not be utilized as carbon sources but they played a comprehensive role in the secondary metabolites synthesis. Our data indicated that MCC and D-galactose might be further industrialized for higher GAs production in G. lucidum in submerged fermentation.

Comparative study on lipase production using solid state and submerged fermentation systems by several fungal strains and the predicted molecular characteristics

Background: Lipases produced from microbial fermentation systems belong to the group of hydrolase enzymes and have tremendous commercial applications. The performance of solid state and submerged fermentation in producing lipase by several fungal strains was compared and the structure and functions of the lipases were predicted by molecular prediction studies. Methods: Lipase production was investigated using both solid state fermentation (SSF) and submerged liquid fermentation (SLF); with palm kernel cake as the fermentation substrate for SSF. Lipase activity, protease activity, total protein and biomass content were assayed. The predictive molecular characterization techniques were employed to determine possible structure and function of the lipases. Results: All fungal strains tested showed substantially higher lipase activity in SSF compared to SLF except for Trichoderma viride SDTC EDF 002. Aspergillus niger SDTC SRW-4 (44.43 U g-1; 176.36 mg g-1) and Aspergillus niger DSMZ 2466 (42.05 U g-1; 176.28 mg g-1) showed the highest lipase activities and total protein content. All lipases showed the presence of “lipase 3” domain with conserved dyad catalytic site of two residues (Ser-Asp) unlike several other esterase lipases with triad catalytic site (Ser-Asp/Glu-His). Predicted pI range of lipases was 4.22 to 8.28 with molecular weight ranging from 31.6 kDa to 54.1 kDa. Conclusions: Production of lipase by Aspergillus niger SDTC SRW-4 and Aspergillus niger DSMZ 2466 using palm kernel cake as substrate was substantially higher in SSF as compared to SLF. Lipases produced by these fungus were predicted to have similar properties and functionality of triacylglycerol lipases (EC 3.1.1.3).

A New Temperature Control Shifting Strategy for Enhanced Triterpene Production by Ganoderma lucidum G0119 Based on Submerged Liquid Fermentation.

Temperature control is a very important factor on triterpene productivity in submerged liquid fermentation. Temperature effects from 23 to 32°C on triterpene production by Ganoderma lucidum G0119 were investigated in 6-L stirred fermentor. Logistic and Luedeking-Piret equations were used to estimate the mycelial growth and triterpene production kinetics by regression analysis. On that basis, a temperature-shifting fermentation control strategy was established. From 0 to 61h, culturing was performed at 32°C to get high specific mycelial growth rate. Between 62 and 127h, the temperature was decreased stepwise from 31 to 30°C to maintain high triterpene productivity. After 128h, temperature was maintained at 29°C to minimize triterpene production inhibition and sustain high productivity. Elevated triterpene level (0.269gL-1), yield (0.0101gg-1), and productivity (0.00207g (Lh)-1) were achieved representing 27.32, 13.94, and 37.11% higher than submerged liquid fermentation at constant temperature of 29°C, respectively, feasible for the industrial scale.