Response surface analysis for the production of an enantioselective lipase from Aspergillus niger by solid-state fermentation

Advances in Recombinant Lipases: Production, Engineering, Immobilization and Application in the Pharmaceutical Industry

Lipases are one of the most used enzymes in the pharmaceutical industry due to their efficiency in organic syntheses, mainly in the production of enantiopure drugs. From an industrial viewpoint, the selection of an efficient expression system and host for recombinant lipase production is highly important. The most used hosts are Escherichia coli and Komagataella phaffii (previously known as Pichia pastoris) and less often reported Bacillus and Aspergillus strains. The use of efficient expression systems to overproduce homologous or heterologous lipases often require the use of strong promoters and the co-expression of chaperones. Protein engineering techniques, including rational design and directed evolution, are the most reported strategies for improving lipase characteristics. Additionally, lipases can be immobilized in different supports that enable improved properties and enzyme reuse. Here, we review approaches for strain and protein engineering, immobilization and the application of lipases in the pharmaceutical industry.

Thermo-alkali-stable lipase from a novel Aspergillus niger: statistical optimization, enzyme purification, immobilization and its application in biodiesel production

The influences of nutritional components affecting lipase production from the new Aspergillus niger using wheat bran as substrate were studied by employing Plackett-Burman and central composite statistical designs. Out of the 11 medium components tested, sucrose, KH₂PO₄ and MgSO₄ at final concentrations of 3.0, 1.0 and 0.5 g/L, respectively, were reported to contribute positively to enzyme production (20.09 ± 0.98 U/g ds). The enzyme was purified through ammonium sulfate precipitation followed by Sephadex G-100 gel filtration. Molecular mass of the purified lipase was 57 kDa as evident on SDS-PAGE. Different methods of immobilization were studied and the highest immobilization yield of 81.7 ± 2.18% was reported with agarose (2%) and the optimum temperature was raised from 45 to 50 °C. Immobilized lipase could retain 80% of its original activity at 60 °C after 1 hr of incubation, and was stable at pH values between neutral and alkaline pH. Lipase-catalyzed transesterification process of fungal oil resulted in a fatty acid methyl ester yield consisting of a high percentage of polyunsaturated fatty acids (83.6%), making it appropriate to be used as winter-grade biodiesel. The operational stability studies revealed that the immobilized lipase could keep 70% of its total activity after 5 cycles of the transesterification process.

Novel Bacillus subtilis IND19 cell factory for the simultaneous production of carboxy methyl cellulase and protease using cow dung substrate in solid-substrate fermentation

BACKGROUND

Hydrolytic enzymes, such as cellulases and proteases, have various applications, including bioethanol production, extraction of fruit and vegetable juice, detergent formulation, and leather processing. Solid-substrate fermentation has been an emerging method to utilize low-cost agricultural residues for the production of these enzymes. Although the production of carboxy methyl cellulase (CMCase) and protease in solid state fermentation (SSF) have been studied extensively, research investigating multienzyme production in a single fermentation process is limited. The production of multienzymes from a single fermentation system could reduce the overall production cost of enzymes. In order to achieve enhanced production of enzymes, the response surface methodology (RSM) was applied.

RESULTS

Bacillus subtilis IND19 utilized cow dung substrates for the production of CMCase and protease. A central composite design and a RSM were used to determine the optimal concentrations of peptone, NaH2PO4, and medium pH. Maximum productions of CMCase and protease were observed at 0.9 % peptone, 0.78 % NaH2PO4, and medium pH of 8.41, and 1 % peptone, 0.72 % NaH2PO4, and medium pH of 8.11, respectively. Under the optimized conditions, the experimental yield of CMCase and protease reached 473.01 and 4643 U/g, which were notably close to the predicted response (485.05 and 4710 U/g). These findings corresponded to an overall increase of 2.1- and 2.5-fold in CMCase and protease productions, respectively.

CONCLUSIONS

Utilization of cow dung for the production of enzymes is critical to producing multienzymes in a single fermentation step. Cow dung is available in large quantity throughout the year. This report is the first to describe simultaneous production of CMCase and protease using cow dung. This substrate could be directly used as the culture medium without any pretreatment for the production of these enzymes at an industrial scale.

Optimization and partial purification of a high-activity lipase synthesized by a newly isolated Acinetobacter from offshore waters of the Caspian Sea under solid-state fermentation

A new aerobic mesophilic bacterium was isolated from the southern coastal waters of the Caspian Sea which substantially produced an extracellular lipase in solid-state fermentation using milled coriander seeds (MCS) as support substrate.

The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: a review

The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.

Encapsulation in a sol-gel matrix of lipase from Aspergillus niger obtained by bioconversion of a novel agricultural residue

Lipase from Aspergillus niger was obtained from the solid-state fermentation of a novel agroindustrial residue, pumpkin seed flour. The partially purified enzyme was encapsulated in a sol-gel matrix, resulting in an immobilization yield of 71.4 %. The optimum pH levels of the free and encapsulated enzymes were 4.0 and 3.0, respectively. The encapsulated enzyme showed greater thermal stability at temperatures of 45 and 60 °C than the free enzyme. The positive influence of the encapsulation process was observed on the thermal stability of the enzyme, since a longer half-life t 1/2 and lower deactivation constant were obtained with the encapsulated lipase when compared with the free lipase. Kinetic parameters were found to follow the Michaelis-Menten equation. The K m values indicated that the encapsulation process reduced enzyme-substrate affinity and the V max was about 31.3 % lower than that obtained with the free lipase. The operational stability was investigated, showing 50 % relative activity up to six cycles of reuse at pH 3.0 at 37 °C. Nevertheless, the production of lipase from agroindustrial residue associated with an efficient immobilization method, which promotes good catalytic properties of the enzyme, makes the process economically viable for future industrial applications.

Application of Plackett-Burman Experimental Design for Lipase Production by Aspergillus niger Using Shea Butter Cake

Plackett-Burman design was used to efficiently select important medium components affecting the lipase production by Aspergillus niger using shea butter cake as the main substrate. Out of the eleven medium components screened, six comprising of sucrose, (NH₄)₂SO₄, Na₂HPO₄, MgSO₄, Tween-80, and olive oil were found to contribute positively to the overall lipase production with a maximum production of 3.35 U/g. Influence of tween-80 on lipase production was investigated, and 1.0% (v/w) of tween-80 resulted in maximum lipase production of 6.10 U/g. Thus, the statistical approach employed in this study allows for rapid identification of important medium parameters affecting the lipase production, and further statistical optimization of medium and process parameters can be explored using response surface methodology.

New tools for exploring "old friends-microbial lipases"

Fat-splitting enzymes (lipases), due to their natural, industrial, and medical relevance, attract enough attention as fats do in our lives. Starting from the paper that we write, cheese and oil that we consume, detergent that we use to remove oil stains, biodiesel that we use as transportation fuel, to the enantiopure drugs that we use in therapeutics, all these applications are facilitated directly or indirectly by lipases. Due to their uniqueness, versatility, and dexterity, decades of research work have been carried out on microbial lipases. The hunt for novel lipases and strategies to improve them continues unabated as evidenced by new families of microbial lipases that are still being discovered mostly by metagenomic approaches. A separate database for true lipases termed LIPABASE has been created recently which provides taxonomic, structural, biochemical information about true lipases from various species. The present review attempts to summarize new approaches that are employed in various aspects of microbial lipase research, viz., screening, isolation, production, purification, improvement by protein engineering, and surface display. Finally, novel applications facilitated by microbial lipases are also presented.

Use of evolutionary operation (EVOP) factorial design technique to develop a bioprocess using grease waste as a substrate for lipase production

The aim of the present work was to develop a bioprocess using EVOP-factorial design technique employing grease waste as a substrate for the production of lipase. A newly isolated fungal strain of Penicillium chrysogenum was explored for the fermentation process. Solid-state fermentation (SSF) was carried out using grease waste and Czapek-dox medium, supplemented with wheat bran. The yield of lipase was 38 U/ml when SSF was carried out at 32 °C for 8 days and grease:wheat bran:Czapek-dox media in 1:1:2 (w/w/v). Different physicochemical parameters affecting the production of lipase were optimized through evolutionary operation (EVOP) factorial design technique and after optimization yield was enhanced up to 46 U/ml at 30 °C, pH 7.0 with 1:1:2 (w/w/v) grease waste:wheat bran:Czapek-dox media. Industrial grease waste has never been reported before for the production of industrially important lipase enzyme.