Optimization of process parameters influencing the submerged fermentation of extracellular lipases from Pseudomonas aeruginosa, candida albicans and Aspergillus flavus

Preparation, purification, and biochemical of fat-degrading bacterial enzymes from pig carcass compost and its application

BACKGROUND

A lot of kitchen waste oil is produced every day worldwide, leading to serious environmental pollution. As one of the environmental protection methods, microorganisms are widely used treating of various wastes. Lipase, as one of the cleaning agents can effectively degrade kitchen waste oil. The composting process of pig carcasses produces many lipase producing microorganisms, rendering compost products an excellent source for isolating lipase producing microorganisms. To our knowledge, there are no reports isolating of lipase producing strains from the high temperature phase of pig carcass compost.

METHODOLOGY

Lipase producing strains were isolated using a triglyceride medium and identified by 16S rRNA gene sequencing. The optimal fermentation conditions for maximum lipase yield were gradually optimized by single-factor tests. The extracellular lipase was purified by ammonium sulfate precipitation and Sephadex G-75 gel isolation chromatography. Amino acid sequence analysis, structure prediction, and molecular docking of the purified protein were performed. The pure lipase's enzymatic properties and application potential were evaluated by characterizing its biochemical properties.

RESULTS

In this study, a lipase producing strain of Bacillus sp. ZF2 was isolated from pig carcass compost products, the optimal fermentation conditions of lipase: sucrose 3 g/L, ammonium sulfate 7 g/L, Mn2+ 1.0 mmol/L, initial pH 6, inoculum 5%, temperature 25 ℃, and fermentation time 48 h. After purification, the specific activity of the purified lipase reached 317.59 U/mg, a 9.78-fold improvement. Lipase had the highest similarity to the GH family 46 chitosanase and molecular docking showed that lipase binds to fat via two hydrogen bonds at Gln146 (A) and Glu203 (A). Under different conditions (temperature, metal ions, organic solvents, and surfactants), lipase can maintain enzymatic activity. Under different types of kitchen oils, lipase has low activity only for 'chicken oil', in treating other substrates, the enzyme activity can exceed 50%.

CONCLUSIONS

This study reveals the potential of lipase for waste oil removal, and future research will be devoted to the application of lipase.

Characterization of Detergent-Compatible Lipases from Candida albicans and Acremonium sclerotigenum under Solid-State Fermentation

The purpose of this study was to compare and explore the potential of two distinct lipases at industrial levels after their production using wheat bran substrate in solid-state fermentation. Lipases from Candida albicans (C. albicans) and Acremonium sclerotigenum (A. sclerotigenum) were characterized to assess their compatibility and suitability for use in laundry detergents. The effects of pH, temperature, metal ions, inhibitors, organic solvents, and various commercially available detergents on these lipases were studied in order to compare their activity and stability profiles and check their stain removal ability. Both lipases remained stable across the wide pH (7-10) and temperature (30-50 °C) ranges. C. albicans lipase exhibited optimum activity (51.66 U/mL) at pH 7.0 and 37 °C, while A. sclerotigenum lipase showed optimum activity (52.12 U/mL) at pH 8.0 and 40 °C. The addition of Ca2+ and Mg2+ ions enhanced their activities, while sodium dodecyl sulfate (SDS) and ethylenediamine tetraacetic acid (EDTA) reduced their activities. Lipase from both strains showed tolerance to various organic solvents and considerable stability and compatibility with commercially available laundry detergents (>50%); however, A. sclerotigenum lipase performed slightly better. Characterization of these crude lipases showed nearly 60% relative activity after incubation for 2 h in various detergents, thus suggesting their potential to be employed in the formulation of laundry detergents with easy and efficient enzyme production. The production of thermostable and alkaline lipases from both strains makes them an attractive option for economic gain by lowering the amount of detergent to be used, thus reducing the chemical burden on the environment.

Assessment of cultivation parameters influencing pectinase production by Aspergillus niger LFP-1 in submerged fermentation

BACKGROUND

Pectinase is helpful in food and beverage industries, particularly in the preparation of fruit juice, the extraction of vegetable oil, and the fermentation of coffee. The current work aimed to screen Aspergillus niger LFP-1, a recently identified fungal strain, for its ability to produce pectinase and to ascertain the contribution of various physicochemical factors to pectinase production.

RESULTS

The primary and secondary pectinase activity screenings by Aspergillus niger LFP-1 were performed using pectin screening agar and shake flask system, respectively. The finding revealed that the locally isolated strain is able to secrete favourable pectinase production. Before improvement, the pectinase production was 0.88 ± 0.09 U/mL. However, the improved conditions such as 6 days of the cultivation period, agitation speed of 150 rpm, inoculum size of 1 × 10⁶ spores/mL, 2.5% (w/v) citrus pectin, and 0.4% (w/v) ammonium nitrate could significantly increase pectinase production up to 7.41 ± 0.24 U/mL, representing an 88% increase. In this study, supplementing 2.5% (w/v) citrus pectin to the culture medium as a carbon source increased enzyme production by up to 3.07 ± 0.17 U/mL. Meanwhile, 0.4% (w/v) ammonium nitrate was used as a nitrogen source yielding the highest enzyme activity with a value of 6.86 ± 0.07 U/mL.

CONCLUSION

Thus, the locally isolated fungal strain, A. niger LFP-1 has outstanding pectinase-producing capability and can be utilized for the commercial production of pectinase. The improved cultural conditions significantly increase pectinase production and shorten the incubation period from 8 days (before improvement) to 6 days (after improvement).

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.

Comparative Studies of Pectinase Production by Bacillus subtilis strain Btk 27 in Submerged and Solid-State Fermentations

The request for enzymes in the global market is expected to rise at a fast pace in recent years. With this regard, there has been a great increase in industrial applications of pectinase owing to their significant biotechnological uses. This study was undertaken with main objectives of meeting the growing industrial demands of pectinase, by improving the yield without increasing the cost of production. In addition, this research highlights the underestimated potential of agroresidues for the production of biotechnologically important products. In this study, the maximum pectinase production attained was using wheat bran, among the tested agroresidues. The production of pectinase was improved from 10.1 ± 1.4 U/ml to 66.3 ± 1.2 U/ml in submerged fermentation whereas it was in solid state fermentation from 800.0 ± 16.2 U/g to 1272.4 ± 25.5 U/g. The maximum pectinase production was observed using YEP (submerged fermentation) and wheat bran (solid state fermentation) at initial pH of 6.5, at 37°C and by supplementing the medium with 3 mM MgSO4.7H2O.

Purification and characterization of a surfactant-compatible lipase from Aspergillus tamarii JGIF06 exhibiting energy-efficient removal of oil stains from polycotton fabric

An extracellular lipase with 23,666.66 U/ml/min activity was produced by Aspergillus tamarii JGIF06 under submerged fermentation in mineral salt medium containing coconut oil (2.5 % v/v), tryptone (2 % w/v) and ammonium chloride (2 % w/v), with initial pH of 5 ± 0.2, incubated at 25 °C for 7 days on a rotary shaker at 120 rpm. A 7.9-fold increase in lipase-specific activity was recorded after purification by DEAE Sepharose ion exchange and Sephadex G200 column chromatography. The apparent molecular mass of this enzyme was revealed as 50 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis. The optimal lipase activity was recorded at pH 4 and 37 °C. The enzyme revealed broad specificity towards different vegetable oils. The K_m and V_max of the lipase on olive oil was found to be 330.4 mg and 53,690 U/ml/min, respectively. The lipase activity was stable in the presence of surfactants such as cetrimonium bromide, sodium dodecyl sulphate and Tween 80, and metal ions and reagents such as Ca²⁺, Ba²⁺ and 2-mercaptoethanol. However, the activity was greatly reduced in the presence of organic solvents such as chloroform. The stain removal potential of the crude lipase was determined on polycotton fabric pieces stained with peanut oil. Lipase added to cold water alone significantly enhanced the removal of stain by 152 %. The addition of lipase also improved the stain removal efficiency of a commercially available detergent in the presence of either cold (25 ± 2 °C) or hot (65 ± 2 °C) water. The current findings suggest the potentiality of this enzyme for energy-efficient biocatalytic application.