Multipurpose fixed-bed bioreactor to simplify lipase production by solid-state fermentation and application in biocatalysis

Exploring the Biochemical and Nutra-Pharmaceutical Prospects of Some Thymus Species - A Review

The Thymus genus includes various medicinal and aromatic species, cultivated worldwide for their unique medicinal and economic value. Besides, their conventional use as a culinary flavoring agent, Thymus species are well-known for their diverse biological effects, such as antioxidant, anti-fungal, anti-bacterial, anti-viral, anti-tumor, anti-inflammatory, anti-cancer, and anti-hypertensive properties. Hence, they are used in the treatment of fever, colds, and digestive and cardiovascular diseases. The pharmaceutical significance of Thymus plants is due to their high levels of bioactive components such as natural terpenoid phenol derivatives (p-cymene, carvacrol, thymol, geraniol), flavonoids, alkaloids, and phenolic acids. This review examines the phytochemicals, biological properties, functional food, and nutraceutical attributes of some important Thymus species, with a specific focus on their potential uses in the nutra-pharmaceutical industries. Furthermore, the review provides an insight into the mechanisms of biological activities of key phytochemicals of Thymus species exploring their potential for the development of novel natural drugs.

Simultaneous lipase production and immobilization: morphology and physiology study of Penicillium simplicissimum in submerged and solid-state fermentation with polypropylene as an inert support

The influence of different carbon sources (glucose (G), olive oil (O), and a combination of both (GO)) in the physiology (biomass and lipase production) and morphology (light and environmental and scanning electron microscopy) of the fungus Penicillium simplicissimum by applying submerged (SmF) and solid-state (SSF) fermentations was investigated. The cultivation was carried out using polypropylene as hydrophobic inert support in SmF and SSF to understand better the influence of a support for the fungus growth and also provides the immobilization of lipases during its production. Micrographs show different morphologies: in SSF, the fungus grows on and inside the inert support independent of the media; in SmF, the formation of high-density spherical pellets obtained in medium GO leads to the best productivity and specific product yield Y_p/x._.Conidiation is observed mainly in SSF, a few in SmF with polypropylene as inert support and not in SmF, which may indicate a stress condition in SSF. Possibly, the morphology acquired by the fungus under stressful conditions may be the key to the higher biomass and lipase productivity at SSF. The developed process with simultaneous production and immobilization of lipase leads to a new promissory biocatalyst once it can be directly applied with no need for downstream processes.

Application of a constrained mixture design for lipase production by Penicillium roqueforti ATCC 10110 under solid-state fermentation and using agro-industrial wastes as substrate

Solid state fermentation (SSF) simulates the natural conditions fungal growth, where the amount of water in the reaction medium must be restricted, thus limiting the use of liquid substrate. An analytical strategy to deal with this limitation is the design of blending with constraints. Thus, the objective of the work was to optimize two constrained waste mixtures for the production of lipase by Penicillium roqueforti ATCC 10110 under SSF, using different substrates that combine solid and liquid waste. For this, the best fermentation time was determined through a fermentative profile, afterwards a restricted-mix design with lower and upper limits of the components of mixture I (cocoa residue, solid palm oil residue and liquid palm oil residue) and II (cocoa residue, mango residue and palm oil residue liquid palm) was applied. By means of Pareto and contour graphs, the maximum production points of lipase in mixtures I (6.67 ± 0.34 U g^-1) and II (6.87 ± 0.35 U g^-1) were obtained. The restricted mixture design proved to be a promising tool in the production of lipase by P. roqueforti ATCC 10110 under SSF since the use of restrictions is useful when intending to combine solid and liquid residues in fermentation processes.

Comparative performance and reusability studies of lipases on syntheses of octyl esters with an economic approach

A suitable immobilized lipase for esters syntheses should be selected considering not only its cost. We evaluated five biocatalysts in syntheses of octyl caprylate, octyl caprate, and octyl laurate, in which conversions higher than 90% were achieved. Novozym^® 435 and non-commercial preparations (including a dry fermented solid) were selected for short-term octyl laurate syntheses using different biocatalysts loadings. By increasing the biocatalyst's loading the lipase's reusability also raised, but without strict proportionality, which resulted in a convergence between the lowest biocatalyst loading and the lowest cost per batch. The use of a dry fermented solid was cost-effective, even using loadings as high as 20.0% wt/wt due to its low obtaining cost, although exhibiting low productiveness. The combination of biocatalyst's cost, esterification activity, stability, and reusability represents proper criteria for the choice. This kind of assessment may help to establish quantitative goals to improve or to develop new biocatalysts.

Production of a fermented solid containing lipases from Penicillium roqueforti ATCC 10110 and its direct employment in organic medium in ethyl oleate synthesis

The production and direct employment in organic medium in the ethyl-oleate synthesis of a fermented solid (FS) containing lipases by Penicillium roqueforti ATCC 10110 (PR10110) was investigated. For the production of this FS, the solid-state fermentation of different agroindustrial waste was used, such as: cocoa shell, sugarcane bagasse, sugarcane bagasse with cocoa shell, and cocoa shell with soybean oil and nutrient solution. The response surface methodology was used to study the effect of independent variables of initial moisture content and inductor concentration, as carbon source and inducer on lipase production. The characterization of the fermented solid in organic medium was also carried out. The highest lipase activity (53 ± 5 U g^-1 ) was 16% higher than that obtained with the nonoptimized conditions. The characterization studies observed high stability of the FS in organic solvents for 5 h at 30°C, as well as at different temperatures, and the residual activity was measured against triolein. The FS was also able to catalyze ethyl-oleate synthesis maintaining high relative conversion over five reaction cycles of 96 h at 40°C in n-heptane. These results are promising and highlight the use of the FS containing PR10110 lipases for the first time in biocatalytic processes.

Solid-State Cultivation of Aspergillus niger-Trichoderma reesei from Sugarcane Bagasse with Vinasse in Bench Packed-Bed Column Bioreactor

Solid-state cultivation (SSC) is microbial growth on solid supports under limited water conditions. Citric acid is a microbial aerobic metabolic product with several industrial applications, with production potential that can be obtained by SSF. Several wastes from agro-industries are used in SSF, such as sugarcane bagasse and vinasse. Cultures of mixed fungi or co-cultures are used in this SSF in order to complement the inoculum's xylanolytic enzymes for action on the lignocellulosic material (bagasse). Thus, this study aims to evaluate the effect of inoculum (Aspergillus niger and Trichoderma reesei consortium) in the production of citric acid from sugarcane bagasse impregnated with vinasse using bench packed-bed reactors (PBR). The results show the importance of T. reesei and A. niger in inoculum at a ratio of 50:50 and 25:75, suggesting the use of solid support due to the complementation of the hydrolytic enzymes. The highest concentration of citric acid, approximately 1000 mg L^-1, was obtained for 100 mm of bed height in 48 and 72 h, with maximum glucose yield in citric acid (2.2 mg _{citric acid} mg _glucose^-1). k_La indicates that maintaining solid moisture and liquid film thickness is important to keep the oxygen transfer in SSC.

Microbial lipases and their industrial applications: a comprehensive review

Lipases are very versatile enzymes, and produced the attention of the several industrial processes. Lipase can be achieved from several sources, animal, vegetable, and microbiological. The uses of microbial lipase market is estimated to be USD 425.0 Million in 2018 and it is projected to reach USD 590.2 Million by 2023, growing at a CAGR of 6.8% from 2018. Microbial lipases (EC 3.1.1.3) catalyze the hydrolysis of long chain triglycerides. The microbial origins of lipase enzymes are logically dynamic and proficient also have an extensive range of industrial uses with the manufacturing of altered molecules. The unique lipase (triacylglycerol acyl hydrolase) enzymes catalyzed the hydrolysis, esterification and alcoholysis reactions. Immobilization has made the use of microbial lipases accomplish its best performance and hence suitable for several reactions and need to enhance aroma to the immobilization processes. Immobilized enzymes depend on the immobilization technique and the carrier type. The choice of the carrier concerns usually the biocompatibility, chemical and thermal stability, and insolubility under reaction conditions, capability of easy rejuvenation and reusability, as well as cost proficiency. Bacillus spp., Achromobacter spp., Alcaligenes spp., Arthrobacter spp., Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened large scale for lipase production. Lipases as multipurpose biological catalyst has given a favorable vision in meeting the needs for several industries such as biodiesel, foods and drinks, leather, textile, detergents, pharmaceuticals and medicals. This review represents a discussion on microbial sources of lipases, immobilization methods increased productivity at market profitability and reduce logistical liability on the environment and user.

Reduction of scum accumulation through the addition of low-cost enzymatic extract in the feeding of high-rate anaerobic reactor

This work evaluates the reduction of scum accumulation on the top surface of upflow anaerobic sludge blanket (UASB) reactors by the addition of hydrolytic enzymes in their feed. For over 1 year, two UASB reactors of 1.4 L were maintained at 30 °C and continuously fed with synthetic domestic wastewater (containing 150 mg/L of soybean oil) under a hydraulic retention time of 10 h. The Control reactor was only fed with synthetic wastewater. Beginning at the 226th day of operation, low-cost hydrolytic enzymes (obtained by solid-state fermentation of Aspergillus terreus, a fungus isolated from a primary sewage sludge) were added into the feed of the other reactor (Test) for a lipase activity of 24 U/L, considerably reducing the formation of scum. In the Test reactor, the scum showed oil and grease (O&G) concentration between 0.8 and 1.3 g/L and an accumulation rate of 20 to 27 mg O&G/d. In the Control reactor, the scum had values twice as high (1.5-2.5 g/L and 34-51 mg O&G/d, respectively) and there were more operational problems. During the entire period of operation, both reactors presented high chemical oxygen demand removal (>80%), with no loss of effluent quality due to the addition of the enzymes.