Production, recovery and purification of a recombinant β-galactosidase by expanded bed anion exchange adsorption

Leveraging multiomics approaches for producing lignocellulose degrading enzymes

Lignocellulosic materials form the building block of 50% of plant biomass comprising non-chewable agri-components like wheat straw, rice stubbles, wood shavings and other crop residues. The degradation of lignin, cellulose and hemicellulose is complicated and presently being done by chemical process for industrial application through a very energy intensive process. Lignin degradation is primarily an oxidative process where the enzyme lignin peroxidase digests the polymer into smaller fragments. Being a recalcitrant component, higher lignin content poses a challenge of lower recovery of product for industrial use. Globally, the scientists are working on leveraging fungal biotechnology for using the lignocellulose degrading enzymes secreted by actinomycetes and basidiomycetes fungal groups. Enzymes contributing to degradation of lignin are mainly performing the function of modifying the lignin and degrading the lignin. Ligninolytic enzymes do not act as an independent reaction but are vital to complete the degradation process. Microbial enzyme technology is an emerging green tool in industrial biotechnology for commercial application. Bioprocessing of lignocellulosic biomass is challenged by limitations in enzymatic and conversion process where pretreatment and separation steps are done to remove lignin and hydrolyze carbohydrate into fermentable sugars. This review highlights recent advances in molecular biotechnology, lignin valorization, sequencing, decipher microbial membership, and characterize enzyme diversity through 'omics' techniques. Emerging techniques to characterize the interwoven metabolism and spatial interactions between anaerobes are also reviewed, which will prove critical to developing a predictive understanding of anaerobic communities to guide in microbiome engineering This requires more synergistic collaborations from microbial biotechnologists, bioprocess engineers, enzymologists, and other biotechnological fields.

Microbial Enzyme Production Using Lignocellulosic Food Industry Wastes as Feedstock: A Review

Enzymes are of great importance in the industry due to their substrate and product specificity, moderate reaction conditions, minimal by-product formation and high yield. They are important ingredients in several products and production processes. Up to 30% of the total production cost of enzymes is attributed to the raw materials costs. The food industry expels copious amounts of processing waste annually, which is mostly lignocellulosic in nature. Upon proper treatment, lignocellulose can replace conventional carbon sources in media preparations for industrial microbial processes, such as enzyme production. However, wild strains of microorganisms that produce industrially important enzymes show low yield and cannot thrive on artificial substrates. The application of recombinant DNA technology and metabolic engineering has enabled researchers to develop superior strains that can not only withstand harsh environmental conditions within a bioreactor but also ensure timely delivery of optimal results. This article gives an overview of the current complications encountered in enzyme production and how accumulating food processing waste can emerge as an environment-friendly and economically feasible solution for a choice of raw material. It also substantiates the latest techniques that have emerged in enzyme purification and recovery over the past four years.

Recovery and purification of a Kluyvermyces lactis β-galactosidase by Mixed Mode Chromatography

Mixed Mode Chromatography (MMC) is a potential separation technique that allows simultaneous ionic and hydrophobic interactions between the adsorbent and the adsorbate. The aim of this work was to assess the recovery and purification of a Kluyveromyces lactis β-galactosidase employing MMC. Protein precipitation and dialysis were performed in order to concentrate the enzyme of interest and eliminate cell debris and other interferences inherent in the fermentation medium. The best conditions for both adsorption and desorption were attained by a non-factorial Central Composite Experimental Design and employed in the chromatographic runs with resin CAPTO MMC. Fermentation yielded mean values of total enzyme concentration of 0.44 mg/mL, enzymatic activity (employing lactose as a substrate) of 74 U/mL and specific activity of 168 U/mg. The Purification Factor (PF) obtained was of 1.17. After precipitation and dialysis, the subsequent chromatographic run resulted in recovery values ​​of 41.0 and 48.2% of total protein concentration and enzymatic activity, respectively. SDS-PAGE electrophoresis confirmed the purification evolution throughout the unit operations employed, attesting the feasibility of the technique to obtain enzymes with not only considerable degree of purity but also possessing high-added value.

Evaluation and characterization of axial distribution in expanded bed: II. Liquid mixing and local effective axial dispersion

Expanded bed adsorption (EBA) is a promising technology to capture proteins directly from unclarified feedstock. In order to better understand liquid mixing along the bed height in expanded beds, an in-bed sampling method was used to measure residence time distribution at different bed heights. A 2cm diameter nozzle column was tested with agarose raw beads (3% crosslinked agarose containing tungsten carbide). Two settled bed heights (11.5 and 23.1cm) with different expansion factors (1.4-2.6) were investigated and the number of theoretical plates (N), the height equivalent of theoretical plate (HETP) and the local effective axial dispersion coefficient (Dax) were calculated for each bed height-defined zone. The effects of expansion factor, settled bed height and mobile phase were evaluated. The results showed that N increased with the increase of expansion factors, but Dax was unaffected under fixed bed heights. Dax and HETP were found similar as a function of relative bed height for two settled bed heights tested. Higher mobile phase viscosity resulted in stronger axial dispersion. In addition, the local effective Dax under the expansion factor near 2.0 had a different profile which showed minimum values at 0.6-0.8 relative bed height, and the potential mechanism was discussed. These results would be useful for the characterization of axial dispersion and modeling protein adsorption in expanded beds under varying operation conditions.