Surface response methodology for the optimization of lipase production under submerged fermentation by filamentous fungi

Adsorption of extracellular lipase in a packed-bed reactor: an alternative immobilization approach

In light of the growing demand for novel biocatalysts and enzyme production methods, this study aimed to evaluate the potential of Aspergillus tubingensis for producing lipase under submerged culture investigating the influence of culture time and inducer treatment. Moreover, this study also investigated conditions for the immobilization of A. tubingensis lipase by physical adsorption on styrene-divinylbenzene beads (Diaion HP-20), for these conditions to be applied to an alternative immobilization system with a packed-bed reactor. Furthermore, A. tubingensis lipase and its immobilized derivative were characterized in terms of their optimal ranges of pH and temperature. A. tubingensis was shown to be a good producer of lipase, obviating the need for inducer addition. The enzyme extract had a hydrolytic activity of 23 U mL-1 and achieved better performance in the pH range of 7.5 to 9.0 and in the temperature range of 20 to 50 °C. The proposed immobilization system was effective, yielding an immobilized derivative with enhanced hydrolytic activity (35 U g-1), optimum activity over a broader pH range (5.6 to 8.4), and increased tolerance to high temperatures (40 to 60 ℃). This research represents a first step toward lipase production from A. tubingensis under a submerged culture and the development of an alternative immobilization system with a packed-bed reactor. The proposed system holds promise for saving time and resources in future industrial applications.

Study on Optimization of Liquid Fermentation Medium and Antitumor Activity of the Mycelium on Phyllopora lonicerae

Phylloporia lonicerae is an annual fungus that specifically parasitizes living Lonicera plants, offering significant potential for developing new resource food and medicine. However, wild resources and mycelium production of this fungus is limited, and its anti-tumor active ingredients and mechanisms remain unclear, hampering the development of this fungus. Thus, we optimized the fermentation medium of P. lonicerae and studied the anti-tumor activity of its mycelium. The results indicated that the optimum fermentation medium consisted of 2% sucrose, 0.2% peptone, 0.1% KH2PO4, 0.05% MgSO4·7H2O, 0.16% Lonicera japonica petals, 0.18% P fungal elicitor, and 0.21% L. japonica stem. The biomass reached 7.82 ± 0.41 g/l after 15 days of cultivation in the optimized medium, a 142% increase compared with the potato dextrose broth medium, with a 64% reduction in cultivation time. The intracellular alcohol extract had a higher inhibitory effect on A549 and Eca-109 cells than the intracellular water extract, with half-maximal inhibitory concentration values of 2.42 and 2.92 mg/ml, respectively. Graded extraction of the alcohol extract yielded petroleum ether phase, chloroform phase, ethyl acetate phase, and n-butanol phase. Among them, the petroleum ether phase exhibited a better effect than the positive control, with a half-maximal inhibitory concentration of 113.3 μg/ml. Flow cytometry analysis indicated that petroleum ether components could induce apoptosis of Eca-109 cells, suggesting that this extracted component can be utilized as an anticancer agent in functional foods. This study offers valuable technical support and a theoretical foundation for promoting the comprehensive development and efficient utilization of P. lonicerae.

Co-production of lipases and biosurfactants by Bacillus methylotrophicus in solid-state fermentation

The production of biosurfactants and lipases through solid-state fermentation (SSF) processes remains relatively unexplored, especially in bacterial applications. The use of solid matrices, eliminating the need for precipitation and recovery processes, holds significant potential for facilitating bioremediation. This study aimed to simultaneously produce biocompounds via SSF using Bacillus methylotrophicus and employ the fermented substrate for remediating soil contaminated with 20% biodiesel. Initial efforts focused on determining optimal conditions for concurrent lipase and biosurfactant production during an 8-day fermentation period. The selected conditions, including a substrate mix of wheat bran and corn cob (80/20), 75% moisture, 1% glycerol inducer, 2% nitrogen, and 1% sugarcane molasses, resulted in a 24.61% reduction in surface tension and lipase activity of 3.54 ± 1.20 U. Subsequently, a 90-day bioremediation of clayey soil contaminated with biodiesel showcased notable biodegradation, reaching 72.08 ± 0.36% within the initial 60 days. The incorporation of biocompounds, biostimulation, and bioaugmentation (Test E2) contributed to this efficacy. The use of the fermented substrate as a biostimulant and bioaugmentation agent facilitated in situ biocompound production in the soil, leading to a 23.97% reduction in surface tension and lipase production of 1.52 ± 0.19 U.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03910-7.

Agri-residues and agro-industrial waste substrates bioconversion by fungal cultures to biocatalyst lipase for green chemistry: A review

Huge amounts of agri-residues generated from food crops and processing are discarded in landfills, causing environmental problems. There is an urgent need to manage them with a green technological approach. Agri-residues are rich in nutrients such as proteins, lipids, sugars, minerals etc., and provide an opportunity for bioconversion into value-added products. Considering the importance of lipase as a biocatalyst for various industrial applications and its growing need for economic production, a detailed review of bioconversion of agri-residues and agro-industrial substrate for the production of lipase from fungal species from a technological perspective has been reported for the first time. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram was used for the identification and selection of articles from ScienceDirect, Google Scholar, and Scopus databases from 2010 to 2023 (July), and 108 peer-reviewed journal articles were included based on the scope of the study. The composition of agri-residues/agro-industrial wastes, fungal species, lipase production, industrial/green chemistry applications, and the economic impact of using agri-residues on lipase costs have been discussed. Bioconversion procedure, process developments, and technology gaps required to be addressed before commercialization have also been discussed. This process expects to decrease the environmental pollution from wastes, and low-cost lipase can help in the growth of the bioeconomy.

Optimization using response surface methodology of phospholipase C production from Bacillus cereus suitable for soybean oil degumming

This work deals with the optimization of an extracellular phospholipase C production by Bacillus cereus (PLCBc) using Response Surface Methodology (RMS) and Box-Behnken design. In fact, after optimization, a maximum phospholipase activity (51 U/ml) was obtained after 6 h of cultivation on tryptone (10 g/L), yeast extract (10 g/L), NaCl (8.125 g/L), pH 7.5 with initial OD (0.15). The PLCBc activity, esteemed by the model (51 U) was very approximate to activity gutted experimentally (50 U). The PLCBc can be considered as thermoactive phospholipase since it showed a maximal activity of 50 U/mL at 60 °C using egg yolk or egg phosphatidylcholine (PC) as substrate. In addition, the enzyme was active at pH 7 and is stable after incubation at 55 °C for 30 min. The application of B. cereus phospholipase C in soybean oil degumming was investigated. Our results showed that when using enzymatic degumming, the residual phosphorus decrease more than with water degumming, indeed, it passes from 718 ppm in soybean crude oil to 100 ppm and 52 ppm by degumming using water and enzymatic process, respectively. The diacylgycerol (DAG) yield showed an increase of 1.2% with enzymatic degumming compared to soybean crude oil. This makes our enzyme a potential candidate for food industrial applications such as enzymatic degumming of vegetable oils.

Current Insights in Fungal Importance-A Comprehensive Review

Besides plants and animals, the Fungi kingdom describes several species characterized by various forms and applications. They can be found in all habitats and play an essential role in the excellent functioning of the ecosystem, for example, as decomposers of plant material for the cycling of carbon and nutrients or as symbionts of plants. Furthermore, fungi have been used in many sectors for centuries, from producing food, beverages, and medications. Recently, they have gained significant recognition for protecting the environment, agriculture, and several industrial applications. The current article intends to review the beneficial roles of fungi used for a vast range of applications, such as the production of several enzymes and pigments, applications regarding food and pharmaceutical industries, the environment, and research domains, as well as the negative impacts of fungi (secondary metabolites production, etiological agents of diseases in plants, animals, and humans, as well as deteriogenic agents).

Scale-up Lipase Production and Development of Methanol Tolerant Whole-Cell Biocatalyst from Magnusiomyces spicifer SPB2 in Stirred-Tank Bioreactor and Its Application for Biodiesel Production

This study aimed to economically develop the yeast whole-cell biocatalyst from the lipase-secreting Magnusiomyces spicifer SPB2 to serve green biodiesel production. The scaled-up productions of lipases were optimized using a 5-L stirred-tank bioreactor. The maximum extracellular lipase and cell-bound lipase (CBL) yields of 1189.65 U/L and 5603.74 U/L were achieved at 24 h and 60 h, respectively, in the modified IMY medium (pH 5.0) containing 2% of soybean oil as a carbon source and 0.2% Gum Arabic as an emulsifying agent. The optimized cultivation was initiated with an inoculum size of 1 × 107 cells/mL and conducted under an aeration rate of 0.75 vvm with an agitation speed of 400 rpm. The obtained whole-cell biocatalyst of M. spicifer SPB2 was applied to catalyze the transesterification reaction using palm oil and methanol as substrates. The greatest yield of 97.93% fatty acid methyl ester (FAME) was reached at 72 h using a palm oil/methanol ratio of 1:7, indicating high methanol stability of the biocatalyst. Moreover, substrate homogenization accelerated the reaction to achieve FAME production of 97.01% at 48 h and remained stable afterwards. Without homogenization, the highest FAME of 98.20% was obtained at 60 h. The whole-cell biocatalyst prepared from lipase-secreting M. spicifer SPB2 at an up-scaled level greatly enhanced efficiency and feasibility for commercial biodiesel production through a green conversion process.

Industrial applications of fungal lipases: a review

Fungal lipases (triacylglycerol acyl hydrolases EC 3.1.1.3) are significant industrial enzymes and have several applications in a number of industries and fields. Fungal lipases are found in several species of fungi and yeast. These enzymes are carboxylic acid esterases, categorized under the serine hydrolase family, and do not require any cofactor during the catalyzing of the reactions. It was also noticed that processes including the extraction and purification of lipases from fungi are comparatively easier and cheaper than other sources of lipases. In addition, fungal lipases have been classified into three chief classes, namely, GX, GGGX, and Y. Fungal lipases have applications not only in the hydrolysis of fats and oils (triglycerides) but are also involved in synthetic reactions such as esterification, acidolysis, alcoholysis, interesterification, and aminolysis. The production and activity of fungal lipases are highly affected by the carbon source, nitrogen source, temperature, pH, metal ions, surfactants, and moisture content. Therefore, fungal lipases have several industrial and biotechnological applications in many fields such as biodiesel production, ester synthesis, production of biodegradable biopolymers, formulations of cosmetics and personal care products, detergent manufacturing, degreasing of leather, pulp and paper production, textile industry, biosensor development, and drug formulations and as a diagnostic tool in the medical sector, biodegradation of esters, and bioremediation of wastewater. The immobilization of fungal lipases onto different carriers also helps in improving the catalytic activities and efficiencies of lipases by increasing thermal and ionic stability (in organic solvents, high pH, and temperature), being easy to recycle, and inducing the volume-specific loading of the enzyme onto the support, and thus, these features have proved to be appropriate for use as biocatalysts in different sectors.

Effect of Microparticles on Fungal Fermentation for Fermentation-Based Product Productions

Ranging from simple food ingredients to complex pharmaceuticals, value-added products via microbial fermentation have many advantages over their chemically synthesized alternatives. Some of such advantages are environment-friendly production pathways, more specificity in the case of enzymes as compared to the chemical catalysts and reduction of harmful chemicals, such as heavy metals or strong acids and bases. Fungal fermentation systems include yeast and filamentous fungal cells based on cell morphology and culture conditions. However, filamentous fungal fermentation has gained attention in the past few decades because of the diversity of microbial products and robust production of some of the most value-added commodities. This type of fungal fermentation is usually carried out by solid-state fermentation. However, solid-state fermentation poses problems during the scale-up for industrial production. Therefore, submerged fermentation for value-added products is usually preferred for scaling-up purposes. The main problem with submerged fungal fermentation is the formation of complex mycelial clumps or pellets. The formation of such pellets increases the viscosity of the media and hinders the efficient transfer of oxygen and nutrient resources in the liquid phase. The cells at the center of the clump or pellet start to die because of a shortage of resources and, thus, productivity decreases substantially. To overcome this problem, various morphological engineering techniques are being researched. One approach is the use of microparticles. Microparticles are inert particles with various size ranges that are used in fermentation. These microparticles are shown to have positive effects, such as high enzyme productivity or smaller pellets with fungal fermentation. Therefore, this review provides a background about the types of microparticles and summarizes some of the recent studies with special emphasis on the fungal morphology changes and microparticle types along with the applications of microparticles in filamentous fungal fermentations.

Euterpe oleracea Mart (Açaizeiro) from the Brazilian Amazon: A Novel Font of Fungi for Lipase Production

Lipases (EC 3.1.1.3) are hydrolases that catalyze triglycerides hydrolysis in free fatty acids and glycerol. Among the microorganisms that produce lipolytic enzymes, the entophytic fungi stand out. We evaluated 32 fungi of different genera, Pestalotiopsis, Aspergillus, Trichoderma, Penicillium, Fusarium, Colletotrichum, Chaetomium, Mucor, Botryodiplodia, Xylaria, Curvularia, Neocosmospora and Verticillium, isolated from Euterpe oleracea Mart. (Açaizeiro) from the Brazilian Amazon for lipase activity. The presence of lipase was evidenced by the deposition of calcium crystals. The endophytic Pestalotiopsis sp. (31) and Aspergillus sp. (24) with Pz 0.237 (++++) and 0.5 (++++), respectively, were the ones that showed the highest lipolytic activity in a solid medium. Lipase activity was rated in liquid medium, in a different range of temperatures (°C), pH and time (days). The values obtained in the production of lipase by the endophytic fungi were 94% for Pestalotiopsis sp. (31) and 93.87% for Aspergillus sp. (24). Therefore, it is emphasized that the endophytic fungus isolated the E. oleracea palm may be a potential candidate to produce enzymes of global commercial interest.

Bio-fertilizer Affects Structural Dynamics, Function, and Network Patterns of the Sugarcane Rhizospheric Microbiota

Fertilizers and microbial communities that determine fertilizer efficiency are key to sustainable agricultural development. Sugarcane is an important sugar cash crop in China, and using bio-fertilizers is important for the sustainable development of China's sugar industry. However, information on the effects of bio-fertilizers on sugarcane soil microbiota has rarely been studied. In this study, the effects of bio-fertilizer application on rhizosphere soil physicochemical indicators, microbial community composition, function, and network patterns of sugarcane were discussed using a high-throughput sequencing approach. The experimental design is as follows: CK: urea application (57 kg/ha), CF: compound fertilizer (450 kg/ha), BF1: bio-fertilizer (1500 kg/ha of bio-fertilizer + 57 kg/ha of urea), and BF2: bio-fertilizer (2250 kg/ha of bio-fertilizer + 57 kg/ha of urea). The results showed that the bio-fertilizer was effective in increasing sugarcane yield by 3-12% compared to the CF treatment group, while reducing soil acidification, changing the diversity of fungi and bacteria, and greatly altering the composition and structure of the inter-root microbial community. Variance partitioning canonical correspondence (VPA) analysis showed that soil physicochemical variables explained 80.09% and 73.31% of the variation in bacteria and fungi, respectively. Redundancy analysis and correlation heatmap showed that soil pH, total nitrogen, and available potassium were the main factors influencing bacterial community composition, while total soil phosphorus, available phosphorus, pH, and available nitrogen were the main drivers of fungal communities. Volcano plots showed that using bio-fertilizers contributed to the accumulation of more beneficial bacteria in the sugarcane rhizosphere level and the decline of pathogenic bacteria (e.g., Leifsonia), which may slow down or suppress the occurrence of diseases. Linear discriminant analysis (LDA) and effect size analysis (LEfSe) searched for biomarkers under different fertilizer treatments. Meanwhile, support vector machine (SVM) assessed the importance of the microbial genera contributing to the variability between fertilizers, of interest were the bacteria Anaerolineace, Vulgatibacter, and Paenibacillus and the fungi Cochliobolus, Sordariales, and Dothideomycetes between CF and BF2, compared to the other genera contributing to the variability. Network analysis (co-occurrence network) showed that the network structure of bio-fertilizers was closer to the network characteristics of healthy soils, indicating that bio-fertilizers can improve soil health to some extent, and therefore if bio-fertilizers can be used as an alternative to chemical fertilizers in the future alternative, it is important to achieve green soil development and improve the climate.

Optimization of lipase production using fungal isolates from oily residues

Lipases are triacylglycerol hydrolases that catalyze hydrolysis, esterification, interesterification, and transesterification reactions. These enzymes are targets of several industrial and biotech applications, such as catalysts, detergent production, food, biofuels, wastewater treatment, and others. Microbial enzymes are preferable for large scale production due to ease of production and extraction. Several studies have reported that lipases from filamentous fungi are predominantly extracellular and highly active. However, there are many factors that interfere with enzyme production (pH, temperature, medium composition, agitation, aeration, inducer type, and concentration, etc.), making control difficult and burdening the process. This work aimed to optimize the lipase production of four fungal isolates from oily residues (Penicillium sp., Aspergillus niger, Aspergillus sp., and Aspergillus sp.). The lipase-producing fungi isolates were morphologically characterized by optical and scanning electron microscopy. The optimal lipase production time curve was previously determined, and the response variable used was the amount of total protein in the medium after cultivation by submerged fermentation. A complete factorial design 32 was performed, evaluating the temperatures (28 °C, 32 °C, and 36 °C) and soybean oil inducer concentration (2%, 6%, and 10%). Each lipase-producing isolate reacted differently to the conditions tested, the Aspergillus sp. F18 reached maximum lipase production, compared to others, under conditions of 32 °C and 2% of oil with a yield of 11,007 (µg mL-1). Penicillium sp. F04 achieved better results at 36 °C and 6% oil, although for Aspergillus niger F16 was at 36 °C and 10% oil and Aspergillus sp. F21 at 32 °C and 2% oil. These results show that microorganisms isolated from oily residues derived from environmental sanitation can be a promising alternative for the large-scale production of lipases.

Current perspective on production and applications of microbial cellulases: a review

The potential of cellulolytic enzymes has been widely studied and explored for bioconversion processes and plays a key role in various industrial applications. Cellulase, a key enzyme for cellulose-rich waste feedstock-based biorefinery, has increasing demand in various industries, e.g., paper and pulp, juice clarification, etc. Also, there has been constant progress in developing new strategies to enhance its production, such as the application of waste feedstock as the substrate for the production of individual or enzyme cocktails, process parameters control, and genetic manipulations for enzyme production with enhanced yield, efficiency, and specificity. Further, an insight into immobilization techniques has also been presented for improved reusability of cellulase, a critical factor that controls the cost of the enzyme at an industrial scale. In addition, the review also gives an insight into the status of the significant application of cellulase in the industrial sector, with its techno-economic analysis for future applications. The present review gives a complete overview of current perspectives on the production of microbial cellulases as a promising tool to develop a sustainable and greener concept for industrial applications.

Production strategies and biotechnological relevance of microbial lipases: a review

Lipases are enzymes that catalyze the breakdown of lipids into long-chain fatty acids and glycerol in oil-water interface. In addition, they catalyze broad spectrum of bioconversion reactions including esterification, inter-esterification, among others in non-aqueous and micro-aqueous milieu. Lipases are universally produced from plants, animals, and microorganisms. However, lipases from microbial origin are mostly preferred owing to their lower production costs, ease of genetic manipulation etc. The secretion of these biocatalysts by microorganisms is influenced by nutritional and physicochemical parameters. Optimization of the bioprocess parameters enhanced lipase production. In addition, microbial lipases have gained intensified attention for a wide range of applications in food, detergent, and cosmetics industries as well as in environmental bioremediation. This review provides insights into strategies for production of microbial lipases for potential biotechnological applications.

Palm Oil Decanter Cake Wastes as Alternative Nutrient Sources and Biomass Support Particles for Production of Fungal Whole-Cell Lipase and Application as Low-Cost Biocatalyst for Biodiesel Production

This is the first report on the possible use of decanter cake waste (DCW) from palm oil industry as alternative nutrient sources and biomass support particles for whole-cell lipase production under solid-state fermentation (SSF) by newly isolated fungal Aspergillus sp. MS15 and their application as a low-cost and environment-friendly biocatalyst for biodiesel production. The results found that DCW supplemented with 0.1% K2HPO4, 0.05% MgSO4·7H2O, 1% peptone and 2% urea and pH adjusted to 6.0 was optimal for whole-cell lipase production. The optimal moisture content and fermentation temperature was 60% and 37.5 °C, respectively. Environmentally friendly biodiesel production, through either esterification or transesterification using whole-cell lipase immobilized on DCW as a biocatalyst, was optimized. The optimal reaction temperature for both reactions was 37 °C. The whole-cell lipase effectively esterified oleic acid into >95% biodiesel yield through esterification under optimal water activity at 0.71 and an optimal methanol to oleic acid molar ratio of 2:1, and also effectively transesterified palm oil under optimal water activity at 0.81 and an optimal methanol to oil molar ratio of 3:1. The fuel properties of produced biodiesel are close to the international biodiesel standards. These results have shown the circular utilization of palm oil mill waste for the low-cost production of an effective biocatalyst, and may contribute greatly to the sustainability of renewable bioenergy production.

Optimization of lipase production by Penicillium roqueforti ATCC 10110 through solid-state fermentation using agro-industrial residue based on a univariate analysis

Lipases (triacylglycerol hydrolases, EC 3.1.1.3) are a class of enzymes with high industrial importance. An option for the production of this enzyme is through fungal growth via solid-state fermentation (SSF). Thus, this research presents a study of lipase production by Penicillium roqueforti ATCC 10110 through SSF using cocoa bran residues (Theobroma cacao) as a substrate. To achieve maximum lipase production, fermentation time (0 to 120 h) and palm oil (PO) percentage (0 to 50%) were optimized through analysis of one factor at a time (OFAT), with lipase activity as the response. The amount of cocoa was fixed (5 g), the incubation temperature was maintained at 27 °C, and the moisture content was established at 70%. For a 72 h incubation, the highest enzyme activity achieved using SSF without adding PO was 14.67 ± 1.47 U g^-1, whereas with PO (30%), it was 33.33 ± 3.33 U g^-1, thus demonstrating a 44% increase in enzyme activity. Through the OFAT methodology, it was possible to confirm that supplementation with palm residue was efficient and maximized the lipase of P. roqueforti ATCC 10110.

Isolation, screening and molecular characterization of biosurfactant producing bacteria from soil samples of auto repair shops

A total of 107 bacterial strains were isolated from used motor oil contaminated soil samples from auto-repair shops. The isolates were evaluated for their biosurfactant production abilities by employing a series of screening techniques, including hemolytic assay, oil displacement assay, drop-collapse assay, and parafilm M test. The potential biosurfactant producers were characterized by 16S rDNA-based molecular tools and were identified as Proteus mirabilis, Klebsiella pneumoniae, Enterobacter cloacae, Micrococcus sp., Citrobacter sp., and Bacillus sp. The widest clearing zone with a diameter of 6.5 cm was observed upon the addition of cell-free supernatant (CFS) from P. mirabilis SLM-B52 as assayed by the oil displacement test. Remarkable emulsification indexes, equivalent to 42% (against kerosene), 53% (against xylenes), and 50% (against benzene and toluene), were recorded by the CFSs of Micrococcus sp. SLM-B28, P. mirabilis SLM-B85, and K. pneumoniae SLM-B46, respectively. Du Noüy tensiometer analysis showed that biosurfactant produced by P. mirabilis SLM-B52 has the highest surface tension reduction capacity with a value of 30.5 mN m^-1. The emulsifying activity of a CFS from P. mirabilis was also described in this study for the first time. Taking together, biosurfactants from promising bacterial strains have potential application in microorganism-based biodegradation processes of hydrocarbons which cause detrimental effects on the environment.

Application of Lactic Acid Bacteria in Fermentation Processes to Obtain Tannases Using Agro-Industrial Wastes

Bacteria have been used in the food industry to produce flavors, dyes, thickeners, and to increase food value, because bacterial fermentations favor the obtention of different metabolites such as tannins and different nutritional compounds in food. Lactiplantibacillus plantarum was one the first species to be studied for industrial purposes, and its efficacy to obtaining tannins using fermentation processes. Bacterial fermentation helps to obtain a product with an added value of better quality and without the need to use strong solvents that can reduce their quality and safety. To release tannins, it is necessary to subject the substrate to different conditions to activate the enzyme tannin acyl hydrolase (tannase). The tannase-released compounds can have beneficial effects on health such as antioxidant, anticancer and cardioprotective properties, among others. Therefore, this review analyzes tannase release and other metabolites by fermentation processes.

Orchestration an extracellular lipase production from Aspergillus niger MYA 135: biomass morphology and fungal physiology

The impact of biomass morphology and culture conditions on fungal fermentation was widely reviewed in the literature. In this work, we presented three independent experiments in order to evaluate the influence of some of those input factors on a lipase production separately by using the Aspergillus niger MYA 135 and the two-stage fermentation technique. Regarding the culture modality, the biomass was pre-grown in a first reactor. Then, the washed mycelium was transferred to a second reactor to continue the study. Firstly, linear effects of fungal morphology and several physiological parameters on a lipase production were explored using the Plackett-Burman design. The dispersed fungal morphology was confirmed as a proper quality characteristic for producing an extracellular lipase activity. Concerning the impact of the carbon source on the biomass pre-growth, the sucrose (E = 9.923, p < 0.001) and the L-arabinose (E = 4.198, p = 0.009) presented positive and significant effects on the enzyme production. On the contrary, the supplementation of 0.05 g/L CaCl₂ displayed a highly negative and significant effect on this process (E = - 7.390, p < 0.001). Secondly, the relationship between the enzyme production and the input variables N:C ratio, FeCl₃ and olive oil was explored applying the central composite design. Among the model terms, the N:C ratio of the production medium had the most negative and significant influence on the enzyme synthesis. Thus, it was concluded that a low N:C ratio was preferable to increase its production. In addition, the bifunctional role of FeCl₃ on this fungus was presented. Thirdly, a prove of concept assay was also discussed.

Production, purification, characterization, and biological properties of Rhodosporidium paludigenum polysaccharide

The yield of marine red yeast polysaccharide (MRYP) obtained from Rhodosporidium paludigenum was increased by optimizing fermentation conditions, and the pure polysaccharide was extracted by column chromatography. The molecular weight of pure MRYP and the ratio of mannose to glucose in components of MRYP were determined. Antioxidant and antibacterial abilities of MRYP were investigated in vitro and in vivo. The optimal fermentation parameters were as follows: Medium 4, pH = 6.72, temperature = 30.18°C, blades speed = 461.36 r/min; the optimized yield reached 4323.90 mg/L, which was 1.31 times the original yield. The sequence of factors that affected the MRYP yield was the blades speed>pH>temperature. The main components of MRYP were MYH-1 and MYH-2. The molecular weights of MYH-1 and MYH-2 were 246.92 kDa and 21.88 kDa, respectively; they accounted for 53.60% and 28.75% of total polysaccharide. In MYH-1 and MYH-2, the proportion of glucose and mannose accounted for 46.94%, 38.46%, and 67.10%, 7.17%, respectively. In vitro, the ability of scavenging DPPH•, •OH, and •O2− radical was 32.26%, 24.34%, and 22.09%; the minimum inhibitory concentration (MIC) of MRYP was 480 μg/mg. In vivo, MRYP improved the lambs’ body weight, antioxidant enzyme activity, and the number of probiotics, but it reduced the feed/gain (F/G) ratio and the number of pathogenic bacteria in 60-days-old lambs.

The Potential of Single-Cell Oils Derived From Filamentous Fungi as Alternative Feedstock Sources for Biodiesel Production

Microbial lipids, also known as single-cell oils (SCOs), are highly attractive feedstocks for biodiesel production due to their fast production rates, minimal labor requirements, independence from seasonal and climatic changes, and ease of scale-up for industrial processing. Among the SCO producers, the less explored filamentous fungi (molds) exhibit desirable features such as a repertoire of hydrolyzing enzymes and a unique pellet morphology that facilitates downstream harvesting. Although several oleaginous filamentous fungi have been identified and explored for SCO production, high production costs and technical difficulties still make the process less attractive compared to conventional lipid sources for biodiesel production. This review aims to highlight the ability of filamentous fungi to hydrolyze various organic wastes for SCO production and explore current strategies to enhance the efficiency and cost-effectiveness of the SCO production and recovery process. The review also highlights the mechanisms and components governing lipogenic pathways, which can inform the rational designs of processing conditions and metabolic engineering efforts for increasing the quality and accumulation of lipids in filamentous fungi. Furthermore, we describe other process integration strategies such as the co-production with hydrogen using advanced fermentation processes as a step toward a biorefinery process. These innovative approaches allow for integrating upstream and downstream processing units, thus resulting in an efficient and cost-effective method of simultaneous SCO production and utilization for biodiesel production.

Microbial lipase: a new approach for a heterogeneous biocatalyst

Lipases are enzymes employed in several industrial process and their applicability can be increased if these biocatalysts are in the immobilize form. The objective of this work was to study the immobilization of lipase produced by submerged cultivation of Aspergillus sp. by hydrophobic interaction, evaluating its stability and reuse capacity. The immobilization process on octyl-sepharose (C₈) and octadecyl-sepabeads (C₁₈) carriers was possible after the removal of oil excess presented in the fermented broth. The results showed that the enzyme was isolated and concentrated in octyl-sepharose with 22% of the initial activity. To increase the amount of enzyme adsorbed on the carrier, 4 immobilization cycles were performed in a row, on the same carrier, with a final immobilization yield of 151.32% and an increase in the specific activity of 136%. The activity test with immobilized lipase showed that the immobilized enzyme maintained 75% of the initial activity after 20 cycles.

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.

Microbial lipase production: A deep insight into the recent advances of lipase production and purification techniques

Importance of enzymes is ever-rising particularly microbial lipases holding great industrial worth owing to their potential to catalyze a diverse array of chemical reactions in aqueous as well as nonaqueous settings. International lipase market is anticipated to cross USD 797.7 million till 2025, rising at a 6.2% compound annual growth rate from 2017 to 2025. The recent breakthrough in the field of lipase research is the generation of new and upgraded versions of lipases via molecular strategies. For example, integration of rational enzyme design and directed enzyme evolution to attain desired properties in lipases. Normally, purification of lipase with significant purity is achieved through a multistep procedure. Such multiple step approach of lipase purification entails both conventional and novel techniques. The present review attempts to provide an overview of different aspects of lipase production including fermentation techniques, factors affecting lipase production, and purification strategies, with the aim to assist researchers to pick a suitable technique for the production and purification of lipase.

Comparative metabolomics of Phialemonium curvatum as an omnipotent fungus cultivated on crude palm oil versus glucose

BACKGROUND

Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources.

RESULTS

Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC-MS/MS-TripleQ and GC-MS, while untargeted metabolite profiling was performed using LC-MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures.

CONCLUSIONS

Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.

Combinatorial strategies for production improvement of red pigments from Antarctic fungus Geomyces sp

Natural red pigments have been widely used as food and cosmetics additives. However, due to toxic byproducts or allergen issues, it is still necessary to look for some other red pigment products. This study proposed combinatorial strategies to improve production of a new kind of red pigments from the fungus Geomyces WNF-15A, isolated from Antarctica. A high-production medium was developed by statistical experimental design, which was further simplified for industrial use by single-factor experiments. Strain breeding by atmospheric room temperature plasma mutagenesis generated a mutant, Geomyces sp. WNF-15A-M210, which increased production of red pigments by 24.4% and shortened culture phase by 33.3% comparing with the wild-type. The production of red pigments by this mutant favored a weak alkaline condition but required only mild dissolved oxygen tension. Control of initial pH 8.5 (process pH around 7.5) increased red pigments production by 19% comparing with natural condition. Precursor and inhibitor addition experiments indicated that the red pigments were synthesized by polyketide pathway, and feeding 6 mmol/L precursor of sodium acetate by three aliquots at days 3 to 5 improved biosynthesis of red pigments by 27%. Finally, the developed culture process was verified in a 5-L stirred tank bioreactor. The red pigments production of the pH regulation group reached 1.11-fold of the control and 1.95-fold of the precursor regulation group, respectively. This study provides high-production strain, optimized medium, and bioprocess for the possible industrial production of Antarctic Geomyces red pigments in future. PRACTICAL APPLICATION: Antarctic Geomyces red pigments showed high color value, nontoxic characteristic, and good water solubility. It holds potential for industrial use and is under development for food additive in China currently. This study provides an optional manufacturing process for this new kind of red pigments.

Lipases of Endophytic Fungi Stemphylium lycopersici and Sordaria sp.: Application in the synthesis of solketal derived Monoacylglycerols

Monoacylglycerols (MAGs) are amphiphilic compounds with wide range of applications such as emulsifiers, solubility agents, and chiral building blocks. These compounds are currently produced by chemical approaches involving alkaline glycerolysis or esterification under high temperatures and pressure, resulting in low yields and with by-products. Lipase-catalyzed processes have been alternative tools to provide more ecological approaches since MAGs can be obtained under milder reaction conditions and with higher selectivity. However, just a few papers have been explored the potential of endophytic fungi as lipase sources. In this work we summarized the screening of lipolytic activity of endophytic fungus S. lycopersici and Sordaria spp isolated from vegetal species collected in Jurubatiba Sandbank National Park, RJ, Brazil, as well as its applications as biocatalysts on the lipase-catalyzed synthesis of solketal 1-MAG derivatives. As a result, the crude enzymatic extract of S. lycopersici showed 98 U/mL and 110 U/mL of hydrolytic activity after 72 h and 96 h, respectively, against 74 U/mL (96 h) and, 86 U/mL (120 h) expressed by enzymatic extract of Sordaria spp.. Concerning the esterification activity, both crude enzymatic extracts and lyophilized fungi showed about 80 % conversion into ethyl oleate, in 100 min. On solketal derived 1-MAG synthesis, S. lycopersici both lyophilized and immobilized in polyurethane (PU) forms showed more than 75 % of conversion in the presence and absence of organic solvents. On MAG recycle assays, the PU biocatalyst could be reused after five reaction cycles while for the ethyl oleate synthesis, PU biocatalyst could be reused after six reaction cycles. Both microorganisms, immobilized in polyurethane, were successfully applied as biocatalysts in esterification reactions for solketal 1-MAG derivative production, in a solvent-free media.

Response-Surface-Optimized and Scaled-Up Microbial Electrosynthesis of Chiral Alcohols

A variety of enzymes can be easily incorporated and overexpressed within Escherichia coli cells by plasmids, making it an ideal chassis for bioelectrosynthesis. It has recently been demonstrated that microbial electrosynthesis (MES) of chiral alcohols is possible by using genetically modified E. coli with plasmid-incorporated and overexpressed enzymes and methyl viologen as mediator for electron transfer. This model system, using NADPH-dependent alcohol dehydrogenase from Lactobacillus brevis to convert acetophenone into (R)-1-phenylethanol, is assessed by using a design of experiment (DoE) approach. Process optimization is achieved with a 2.4-fold increased yield of 94±7 %, a 3.9-fold increased reaction rate of 324±67 μm h-1 , and a coulombic efficiency of up to 68±7 %, while maintaining an excellent enantioselectivity of >99 %. Subsequent scale-up to 1 L by using electrobioreactors under batch and fed-batch conditions increases the titer of (R)-1-phenylethanol to 12.8±2.0 mm and paves the way to further develop E. coli into a universal chassis for MES in a standard biotechnological process environment.

Optimization of extracellular lipase production by halotolerant Bacillus sp. VITL8 using factorial design and applicability of enzyme in pretreatment of food industry effluents

The effect of macro and micronutrients of media components on lipase production by Bacillus sp. VITL8 was investigated using classical as well as statistical methods. Initially, the carbon source, nitrogen source, inducer and metal ions that affect lipase production were selected using the classical approach. Subsequently, selected nutrients along with other key factors (such as pH, agitation rate, gum acacia and tween 80) were investigated using Placket Burman design. Finally, three significant factors, viz., olive oil, peptone and tween 80 were studied using a 2² full factorial central composite design. Under optimized condition [6% (v/v) of olive oil, 0.7% peptone, 0.9% tween 80 and 25 h of incubation], the enzyme production was found to be 2.2 times higher with an overall enzyme production of 325.0 ± 1.4 U mL^-1. Laboratory scale experiment proved that the enzyme could be utilized for pretreatment of food industry effluent rich in fat and oil (dairy, bakery and poultry). The enzyme was capable of hydrolyzing more than 50% of the initial fat present in all these effluents and enabled the reduction in the levels of biological oxygen demand (BOD) and chemical oxygen demand (COD) of the effluent samples. The study thus reveals the utility of the lipase produced by the halotolerant bacterium Bacillus sp. VITL8 in the pretreatment of industrial effluents contaminated with oil and fat.HighlightsLipase production was enhanced by 2.2-fold using statistical methodsOne of the few reports on lipase production by a halotolerant bacterium, especially by Bacillus sp.Production of 325.0 ± 1.4 U mL^-1 lipase within 25 h by a halotolerant bacteriumPretreatment of food industry effluents using Bacillus sp. VITL8 lipaseImprovement in effluent quality within 8 h of treatment.

Turning cacay butter and wheat bran into substrate for lipase production by Aspergillus terreus NRRL-255

Cacay oil and butter were evaluated as enzymatic inducers for lipase production from Aspergillus terreus NRRL-255 by solid-state fermentation (SSF). Initially, physicochemical characteristics of agro-industrial wastes were evaluated in order to identify a potential solid substrate for lipase production. Higher water absorption index (3.65 g H₂O/g substrate), adequate mineral content, great carbon source, and nitrogen concentration were factors that influenced the choice of wheat bran as a solid substrate. Cacay butter presented the highest lipolytic activity (308.14 U g^-1) in the screening of lipid inducer. Then, the effects of lipid inducer concentration (cacay butter), temperature, pH, moisture, and fermentation time were evaluated on process performance using multivariate statistical methodology. Under optimal conditions, the highest lipase activity observed was 2,867.18 U g^-1. Regarding the lipase characterization, maximum relative activity was obtained at pH 7.0 and at 35 °C. An inhibitory effect was observed for Ca²⁺, Mn²⁺, Zn²⁺, Fe²⁺, and Cu²⁺ ions. Lipase activity was increased with the reduction of sodium dodecyl sulfate (SDS) concentration and the increase of Triton X-100. Therefore, the use of wheat bran as a solid substrate combined with cacay butter demonstrated a substantial lipase production, indicating its biotechnological industrial potential.

Optimization of physical parameters for enhanced production of lipase from Staphylococcus hominis using response surface methodology

Lipase, a versatile hydrolytic enzyme, is gaining more importance in environmental applications such as treatment of oil and grease containing wastewater, pretreatment of solid waste/industrial wastewater for anaerobic treatment. In the present study, the attempts have been made to improve the production of lipase from Staphylococcus hominis MTCC 8980 by optimization of pH, temperature, and agitation speed in lab scale shake flasks culture. The experiments were designed using the full factorial central composite design of experiment. A total of 20 experiments were conducted, and the optimized pH, temperature, and agitation speed were found to be 7.9, 33.1 °C, and 178.4 rpm, respectively. The results of the analysis of variance (ANOVA) test revealed that the linear terms for temperature and agitation were significant (p value < 0.05). Interaction for pH and agitation speed was found to have a significant effect on lipase production from S. hominis MTCC 8980. A 150% increase in enzyme activity was observed under the optimized conditions with the maximum lipase activity of 1.82 U/ml. Further enhancement of enzyme activity can be expected from the optimization of medium components.

Statistical optimization of cultural medium composition of thermoalkalophilic lipase produced by a chemically induced mutant strain of Bacillus atrophaeus FSHM2

Extremophilic microbial derived lipases have been widely applied in different biotechnological processes due to their resistance to harsh conditions such as high salt concentration, elevated temperature, and extreme acidic or alkaline pH. The present study was designed to overproduce the halophilic, thermoalkalophilic lipase of Bacillus atrophaeus FSHM2 through chemically induced random mutagenesis and optimization of cultural medium components assisted by statistical experimental design. At first, improvement of lipase production ability of B. atrophaeus FSHM2 was performed through exposure of the wild bacterial strain to ethidium bromide for 5-90 min to obtain a suitable mutant of lipase producer (designated as EB-5, 4301.1 U/l). Afterwards, Plackett-Burman experimental design augmented to D-optimal design was employed to optimize medium components (olive oil, maltose, glucose, sucrose, tryptone, urea, (NH₄)₂SO₄, NaCl, CaCl₂, and ZnSO₄) for lipase production by the EB-5 mutant. A maximum lipase production of 14,824.3 U/l was predicted in the optimum medium containing 5% of olive oil, 0.5% of glucose, 0.5% of sucrose, 2% of maltose, 2.5 g/l of yeast extract, 1.75 g/l of urea, 1.75 g/l of (NH₄)₂SO₄, 2.5 g/l of tryptone, 2 g/l of NaCl, 1 g/l of CaCl₂, and 1 g/l of ZnSO₄. A mean value of 14,773 ± 576.9 U/l of lipase was acquired from real experiments.

Statistical Optimization by Response Surface Methodology to Enhance Lipase Production by Aspergillus fumigatus

Background:

Lipases have various commercial applications and microorganisms serve as a potential source of production.

Objective:

The aim of this paper was to study the effect of interactions among different production parameters on lipase yield ofAspergillus fumigatus.

Method:

Plackett Burman and Central Composite Design (CCD) were established by using Design Expert software 10.0.

Results:

In the present study, interactions were studied for six different variables such as inoculum size, pH, temperature, galactose concentration, peptone concentration and incubation time. In Plackett-Burman design, galactose concentration, peptone concentration, pH and incubation time were found to be important factors. Using the statistical approach, the optimum factors were found to be as: galactose concentration (1.5%), peptone concentration (1.8%), pH (10.0) and incubation time (72 h) at 45°C under response surface curves. Upon statistical analysis, the coefficient of determination (R2) obtained was 0.9318 which showed that the model was significant.

Conclusion:

The statistical tools used predicted the optimal conditions for the production of the lipase. The optimized parameters were galactose concentration 1.5%, peptone concentration 1.4%, temperature 45°C, pH 10.0 and incubation time of 72 h for obtaining a maximum lipase activity of 6.22 U/ml.

Optimization of novel halophilic lipase production by Fusarium solani strain NFCCL 4084 using palm oil mill effluent

Among different sources of lipases, fungal lipases have continued to attract a wide range of applications. Further, halophilic lipases are highly desirable for biodiesel production due to the need to mitigate environmental pollution caused as result of extensive use of fossil fuels. However, currently, the high production cost limits the industrial application of lipases. In order to address this issue, we have attempted to optimize lipase production by Fusarium solani NFCCL 4084 and using palm oil mill effluent (POME) based medium. The production was optimized using a combinatory approach of Plackett-Burman (PB) design, one factor at a time (OFAT) design and face centred central composite design (FCCCD). The variables (malt extract, (NH4)2SO4, CaCl2, MgSO4, olive oil, peptone, K2HPO4, NaNO3, Tween-80, POME and pH) were analyzed using PB design and the variables with positive contrast coefficient were found to be K2HPO4, NaNO3, Tween-80, POME and pH. The significant variables selected were further analyzed for possible optimum range by using OFAT approach and the findings revealed that K2HPO4, NaNO3, and Tween-80 as the most significant medium components, and thus were further optimized by using FCCCD. The optimum medium yielded a lipase with an activity of 7.8 U/ml, a significant 3.2-fold increase compared to un-optimized medium. The present findings revealed that POME is an alternative and suitable substrate for halophilic lipase production at low cost. Also, it is clearly evident that the combinatory approach employed here proved to be very effective in producing high activity halophilic lipases, in general.

Production of Cold-Active Lipase by Free and Immobilized Marine Bacillus cereus HSS: Application in Wastewater Treatment

Lipases are enzymes that have the potential to hydrolyze triacylglycerol to free fatty acids and glycerol and have various applications. The aim of the present study was to isolate and screen marine bacteria for lipase production, optimize the production, and treat wastewater. A total of 20 marine bacterial isolates were obtained from the Mediterranean Sea and were screened for lipase production. All isolates were found to have lipolytic ability. The differences between the isolates were studied using RAPD-PCR. The most promising lipase producer (isolate 3) that exhibited the highest lipolytic hydrolysis (20 mm) was identified as Bacillus cereus HSS using 16S rDNA analysis and had the accession number MF581790. Optimization of lipase production was carried out using the Plackett-Burman experimental design with cotton seed oil as the inducer under shaking conditions at 10°C. The most significant factors that affected lipase production were FeSO4, KCl, and oil concentrations. By using the optimized culture conditions, the lipase activity increased by 1.8-fold compared with basal conditions. Immobilization by adsorption of cells on sponge and recycling raised lipase activity by 2.8-fold compared with free cells. The repeated reuse of the immobilized B. cereus HSS maintained reasonable lipase activity. A trial for the economic treatment of oily wastewater was carried out. Removal efficiencies of biological oxygen demand, total suspended solids, and oil and grease were 87.63, 90, and 94.7%, respectively, which is promising for future applications.

Realm of Thermoalkaline Lipases in Bioprocess Commodities

For decades, microbial lipases are notably used as biocatalysts and efficiently catalyze various processes in many important industries. Biocatalysts are less corrosive to industrial equipment and due to their substrate specificity and regioselectivity they produced less harmful waste which promotes environmental sustainability. At present, thermostable and alkaline tolerant lipases have gained enormous interest as biocatalyst due to their stability and robustness under high temperature and alkaline environment operation. Several characteristics of the thermostable and alkaline tolerant lipases are discussed. Their molecular weight and resistance towards a range of temperature, pH, metal, and surfactants are compared. Their industrial applications in biodiesel, biodetergents, biodegreasing, and other types of bioconversions are also described. This review also discusses the advance of fermentation process for thermostable and alkaline tolerant lipases production focusing on the process development in microorganism selection and strain improvement, culture medium optimization via several optimization techniques (i.e., one-factor-at-a-time, surface response methodology, and artificial neural network), and other fermentation parameters (i.e., inoculums size, temperature, pH, agitation rate, dissolved oxygen tension (DOT), and aeration rate). Two common fermentation techniques for thermostable and alkaline tolerant lipases production which are solid-state and submerged fermentation methods are compared and discussed. Recent optimization approaches using evolutionary algorithms (i.e., Genetic Algorithm, Differential Evolution, and Particle Swarm Optimization) are also highlighted in this article.

Application of Response Surface Methodology for Optimization of Extracellular Glucoamylase Production by Candida guilliermondii

OBJECTIVE

Glucoamylase is among the most important enzymes in biotechnology. The present study aims to determine better conditions for growth and glucoamylase production by Candida guilliermondii and to reduce the overall cost of the medium using Box-Behnken design with one central point and response surface methodology.

METHODOLOGY

Box-Behnken factorial design based on three levels was carried out to obtain optimal medium combination of five independent variables such as initial pH, soluble starch, CH4N2O, yeast extract and MgSO4. Forty one randomized mediums were incubated in flask on a rotary shaker at 105 rpm for 72 h at 30°C.

RESULTS

The production of biomass was found to be pH and starch dependent, maximum production when the starch concentration was 8 g L-1 and the initial pH was 6, while maximum glucoamylase production was found at 6.5 of initial pH, 4 g L-1 yeast extract and 6 g L-1 starch, whereas yeast extract and urea were highly significant, but interacted negatively. Box-Behnken factorial design used for the analysis of treatment combinations gave a second-order polynomial regression model with R2 = 0.976 for Biomass and R2 = 0.981 for glucoamylase.

CONCLUSION

The final biomass and glucoamylase activity obtained was very close to the calculated parameters according to the p-values (p<0.001), the predicted optimal parameters were confirmed and provides a basis for further studies in baking additives and in the valuation of starch waste products.