Production of a Recombinant Non-Hydroxylated Gelatin Mimetic in Pichia pastoris for Biomedical Applications

Applications of the Methylotrophic Yeast Komagataella phaffii in the Context of Modern Biotechnology

Komagataella phaffii (formerly Pichia pastoris) is a methylotrophic yeast widely used in laboratories around the world to produce recombinant proteins. Given its advantageous features, it has also gained much interest in the context of modern biotechnology. In this review, we present the utilization of K. phaffii as a platform to produce several products of economic interest such as biopharmaceuticals, renewable chemicals, fuels, biomaterials, and food/feed products. Finally, we present synthetic biology approaches currently used for strain engineering, aiming at the production of new bioproducts.

Green biomanufacturing in recombinant collagen biosynthesis: trends and selection in various expression systems

Collagen, classically derived from animal tissue, is an all-important protein material widely used in biomedical materials, cosmetics, fodder, food, etc. The production of recombinant collagen through different biological expression systems using bioengineering techniques has attracted significant interest in consideration of increasing market demand and the process complexity of extraction. Green biomanufacturing of recombinant collagen has become one of the focus topics. While the bioproduction of recombinant collagens (type I, II, III, etc.) has been commercialized in recent years, the biosynthesis of recombinant collagen is extremely challenging due to protein immunogenicity, yield, degradation, and other issues. The rapid development of synthetic biology allows us to perform a heterologous expression of proteins in diverse expression systems, thus optimizing the production and bioactivities of recombinant collagen. This review describes the research progress in the bioproduction of recombinant collagen over the past two decades, focusing on different expression systems (prokaryotic organisms, yeasts, plants, insects, mammalian and human cells, etc.). We also discuss the challenges and future trends in developing market-competitive recombinant collagens.

Biocompatible Triple-Helical Recombinant Collagen Dressings for Accelerated Wound Healing in Microneedle-Injured and Photodamaged Skin

Skin rejuvenation procedures such as microneedling and laser resurfacing have gained global popularity in medical cosmetology, leading to acute skin wounds with persistent pain, erythema, and edema. A variety of dressings have been explored to repair these postoperative skin injuries; however, their inadequate biocompatibility and bioactivity may raise concerns about undesirable efficacy and complications. Herein, we developed biocompatible and nonirritating triple-helical recombinant collagen (THRC) dressings for accelerated healing of microneedle-injured and photodamaged acute skin wounds. Circular dichroism (CD) measurements of THRC from various batches exhibited triple-helical structure characteristics of collagen. Cell experiments using L929 fibroblasts revealed that THRC dressings possess superior biocompatibility and bioactivity, significantly elevating the proliferation and adhesion of fibroblasts. In vivo, skin irritation tests of New Zealand rabbits demonstrated that the THRC dressings are gentle, safe, and non-irritating. Histological analysis of the animal model studies in photodamaged skin wounds using H&E and Masson’s trichrome staining revealed that 4 days of treatment with the THRC dressings effectively healed the damaged dermis by accelerating re-epithelialization and enhancing collagen deposition. In vivo studies of microneedle-injured rat defects showed that THRC dressings of varying concentrations exhibit the same rapid epithelialization rates at 48 h as commercial bovine collagen dressings. The highly biocompatible and bioactive recombinant collagen dressings may provide an advanced treatment of acute skin wounds, indicating attractive applications in postoperative care of facial rejuvenation.

Expression, characterization, and application potentiality evaluation of recombinant human-like collagen in Pichia pastoris

Collagen is a biofunctional protein that has been widely used in many fields, including but not limited to biomedical, cosmetics and skin care, food, and novel materials. Recombinant collagen has great potential as an alternative to collagen extracted from animals because it avoids the immune response, and the yield and properties are stable. However, challenges remain in the industrial application of recombinant collagen, including improving the expression yield, reducing the cost of purification for industry and expanding applications. In this study, a cloning and recombination method was used to heterologously express the recombinant human-like collagen (RHLC) in Pichia pastoris GS115 using the pPIC9k expression vector. The RHLC expression titre was 2.33 g/L via a 5-L fermenter, and the purification was completed within 48 h and was 98% pure. The characteristics of RHLC were investigated. Furthermore, potential applications for RHLC were explored, such as basal collagen sponge preparation, forming films with chitosan and production of collagen hydrolysed peptides. RHLC has various potential applications due to its triple helical structure, thermostability, good biocompatibility and film-forming ability.

Cosmetic Potential of a Recombinant 50 kDa Protein

Collagen and its derivative proteins have been widely used as a major component for cosmetic formulations as a natural ingredient and moisturizer. Most commercially available collagens are animal-derived collagen type I and other forms of collagen, such as type III collagen, are far less prevalent in animals, making extraction and purification extremely difficult and expensive. Here, we report the production of a 50 kDa protein produced in yeast that is 100% identical to the N-terminus of the human type III collagen. This recombinant protein has a larger molecular weight than most incumbent recombinant collagen proteins available for personal care applications. We report the industrialization of both the fermentation and purification processes to produce a final recombinant protein product. This final protein product was shown to be safe for general applications to human skin and compatible with common formulation protocols, including ethanol-based formulations. This recombinant collagen type III protein was also shown to uniquely stimulate both collagen type I and type III production and secretion by primary human dermal fibroblasts. The unique combination of biostimulation, compatibility with beauty product formulations and demonstrated commercial production, make this novel recombinant type III collagen a good candidate for broad application in the cosmetics industry.

Nitrogen supplementation ameliorates product quality and quantity during high cell density bioreactor studies of Pichia pastoris: A case study with proteolysis prone streptokinase

Streptokinase is a well-established cost-effective therapeutic molecule for thrombo-embolic complications. In the current study, a tag-free variant of streptokinase with a native N-terminus (N-rSK) was developed using the Pichia expression system. A three-copy clone was screened that secreted 1062 mg/L of N-rSK in the complex medium at shake flask level. The biologically active (67,552.61 IU/mg) N-rSK recovered by anion exchange chromatography was predicted to contain 15.43% α-helices, 26.43% β-sheets. The fermentation run in a complex medium yielded a poor quality product due to excessive N-rSK degradation. Therefore, modified basal salt medium was also employed during fermentation operations to reduce the proteolytic processing of the recombinant product. The concomitant feeding of 1 g/L/h soya flour hydrolysate with methanol during the protein synthesis phase reduced the proteolysis and yielded 2.29 g/L of N-rSK. The fermentation medium was also supplemented with urea during growth and induction phases. The combined feeding approach of nitrogen-rich soya flour hydrolysate and urea during bioreactor operations showed significant improvement in protein stability and resulted in a 4-fold increase in N-rSK concentration to a level of 4.03 g/L over shake flask. Under optimized conditions, the volumetric productivity and specific product yield were 52.33 mg/L/h and 33.24 mg/g DCW, respectively.

Three Decades of Research on Recombinant Collagens: Reinventing the Wheel or Developing New Biomedical Products?

Collagens provide the building blocks for diverse tissues and organs. Furthermore, these proteins act as signaling molecules that control cell behavior during organ development, growth, and repair. Their long half-life, mechanical strength, ability to assemble into fibrils and networks, biocompatibility, and abundance from readily available discarded animal tissues make collagens an attractive material in biomedicine, drug and food industries, and cosmetic products. About three decades ago, pioneering experiments led to recombinant human collagens' expression, thereby initiating studies on the potential use of these proteins as substitutes for the animal-derived collagens. Since then, scientists have utilized various systems to produce native-like recombinant collagens and their fragments. They also tested these collagens as materials to repair tissues, deliver drugs, and serve as therapeutics. Although many tests demonstrated that recombinant collagens perform as well as their native counterparts, the recombinant collagen technology has not yet been adopted by the biomedical, pharmaceutical, or food industry. This paper highlights recent technologies to produce and utilize recombinant collagens, and it contemplates their prospects and limitations.