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

High-level secretory expression of recombinant type III human-like collagen α1 in Pichia pastoris via multilevel systematic optimization

Collagen is the main component that makes up the internal structure of animals and is extensively used in several industrial fields including food, materials, chemicals, and pharmaceuticals. Despite the variety of preparation methods available, there is significant potential for enhancing the yield of recombinant collagen produced through engineered Pichia pastoris (P. pastoris). Increasing the copy number of the recombinant type III human collagen α1 (hlCOLIII) gene to improve the level of expression of the recombinant protein and co-expression of molecular chaperones to alleviate the resulting endoplasmic reticulum stress further promotes hlCOLIII secretion. By optimizing transcription driven by the AOX1 promoter and improving translation efficiency, a strain of P. pastoris expressing hlCOLIII efficiently was constructed, achieving a yield of 10.3 g/L in a 5 L fermenter. Further, hlCOLIII demonstrated notable antioxidant capacity and performed well in bioactivity analyses, including cell proliferation, migration, and adhesion. This study lays a solid foundation for the scalable industrial production of recombinant collagen and opens new avenues for its exploration in advanced biomedical materials.

Advances in Molecular Function and Recombinant Expression of Human Collagen

Collagen is the main protein found in skin, bone, cartilage, ligaments, tendons and connective tissue, and it can exhibit properties ranging from compliant to rigid or form gradients between these states. The collagen family comprises 28 members, each containing at least one triple-helical domain. These proteins play critical roles in maintaining mechanical characteristics, tissue organization, and structural integrity. Collagens regulate cellular processes such as proliferation, migration, and differentiation through interactions with cell surface receptors. Fibrillar collagens, the most abundant extracellular matrix (ECM) proteins, provide organs and tissues with structural stability and connectivity. In the mammalian myocardial interstitium, types I and III collagens are predominant: collagen I is found in organs, tendons, and bones; collagen II is found in cartilage; collagen III is found in reticular fibers; collagen IV is found in basement membranes; and collagen V is found in nails and hair. Recombinant human collagens, particularly in sponge-like porous formats combined with bone morphogenetic proteins, serve as effective scaffolds for bone repair. Due to their biocompatibility and low immunogenicity, collagens are pivotal in tissue engineering applications for skin, bone, and wound regeneration. Recombinant technology enables the production of triple-helical collagens with amino acid sequences identical to human tissue-derived collagens. This review summarizes recent advances in the molecular functions and recombinant expression of human collagens, with a focus on their biomedical applications.

Innovations and challenges in collagen and gelatin production through precision fermentation

Collagen and gelatin are essential biomaterials widely used in industries such as food, cosmetics, healthcare, and pharmaceuticals. Traditionally derived from animal tissues, these proteins are facing growing demand for more sustainable and ethical production methods. Precision fermentation (PF) offers a promising alternative by using genetically engineered microorganisms to produce recombinant collagen and gelatin. This technology not only reduces environmental impact but also ensures consistent quality and higher yields. In this review, we provide a comprehensive overview of collagen and gelatin production through PF destined for the food sector, exploring key advances in recombinant technologies, synthetic biology, and bioprocess optimization. Challenges such as scaling production, cost-efficiency, and market integration are addressed, alongside emerging solutions for enhancing industrial competitiveness. We also highlight leading companies leveraging PF to drive innovation in the food industry. As PF continues to evolve, future developments are expected to improve efficiency, reduce costs, and expand the applications of recombinant collagen and gelatin, particularly in the food and supplement sectors.

Precision fermentation in the realm of microbial protein production: State-of-the-art and future insights

Food security issues are becoming more pressing due to the world's rapid population expansion and climate change, which also drive up demand for nutrient-dense commodities like meat and cereals. Conventional agricultural practices, which depend on pesticides, fertilizers, and antibiotics, are exacerbating environmental problems, such as antibiotic resistance. Precision fermentation has become a game-changing technique that uses microorganisms to create high-value food ingredients more efficiently and with less negative environmental impact. This method optimizes microbial strains and improves manufacturing processes by utilizing cutting-edge technologies like metabolic engineering and next-generation sequencing. Crucial microorganisms in this technique are filamentous fungi and yeasts, which produce a wide range of products from lipids to proteins. To support microbial growth, an appropriate media formulation is crucial, and downstream processing guarantees the high-quality product recovery. The precise fermentation industry is expanding due to constant advancements and investments, despite obstacles including high production costs and strict regulations. The increased potential of precise fermentation is demonstrated by the commercial trends, which include large investments and the emergence of profitable companies. This review aims to discuss how Precision fermentation has the potential to completely transform the food production industry by providing sustainable alternatives and strengthening the foundation of an increasingly robust and effective food system as well as mentioned the challenges of its implementation.

Identification of a human type XVII collagen fragment with high capacity for maintaining skin health

Collagen XVII (COL17) is a transmembrane protein that mediates skin homeostasis. Due to expression of full length collagen was hard to achieve in microorganisms, arising the needs for selection of collagen fragments with desired functions for microbial biosynthesis. Here, COL17 fragments (27-33 amino acids) were extracted and replicated 16 times for recombinant expression in Escherichia coli. Five variants were soluble expressed, with the highest yield of 223 mg/L. The fusion tag was removed for biochemical and biophysical characterization. Circular dichroism results suggested one variant (sample-1707) with a triple-helix structure at >37 °C. Sample-1707 can assemble into nanofiber (width, 5.6 nm) and form hydrogel at 3 mg/mL. Sample-1707 was shown to induce blood clotting and promote osteoblast differentiation. Furthermore, sample-1707 exhibited high capacity to induce mouse hair follicle stem cells differentiation and osteoblast migration, demonstrating a high capacity to induce skin cell regeneration and promote wound healing. A strong hydrogel was prepared from a chitosan and sample-1707 complex with a swelling rate of >30 % higher than simply using chitosan. Fed-batch fermentation of sample-1707 with a 5-L bioreactor obtained a yield of 600 mg/L. These results support the large-scale production of sample-1707 as a biomaterial for use in the skin care industry.

Diffusion model assisted designing self-assembling collagen mimetic peptides as biocompatible materials

Collagen self-assembly supports its mechanical function, but controlling collagen mimetic peptides (CMPs) to self-assemble into higher-order oligomers with numerous functions remains challenging due to the vast potential amino acid sequence space. Herein, we developed a diffusion model to learn features from different types of human collagens and generate CMPs; obtaining 66% of synthetic CMPs could self-assemble into triple helices. Triple-helical and untwisting states were probed by melting temperature (Tm); hence, we developed a model to predict collagen Tm, achieving a state-of-art Pearson's correlation (PC) of 0.95 by cross-validation and a PC of 0.8 for predicting Tm values of synthetic CMPs. Our chemically synthesized short CMPs and recombinantly expressed long CMPs could self-assemble, with the lowest requirement for hydrogel formation at a concentration of 0.08% (w/v). Five CMPs could promote osteoblast differentiation. Our results demonstrated the potential for using computer-aided methods to design functional self-assembling CMPs.

High-level production of patatin in Pichia pastoris and characterization of N-glycosylation modification in food processing properties

Patatin is an acidic protein found in potatoes that is commonly used in food and pharmaceutical industries due to its excellent emulsifying and gelation abilities. Pichia pastoris is widely used as a host for recombinant protein production because it can incorporate post-translational modifications. In this study, a patatin titre of 2189.8 mg/L was achieved in a 5 L bioreactor using P. pastoris GS115 with signal peptide mutation, dual promoter construction, co-expression of chaperone proteins and optimised fermentation. To enhance the application of recombinant patatin in the food processing field, the level of N-glycosylation was elevated by genetic engineering. Properties of natural patatin, recombinant patatin and patatinL109T (N-glycosylated modified patatin) were investigated including foaming, hydrophobicity and emulsifying abilities. The functional properties of recombinant patatin were enhanced by introducing N-glycosylation, which also improved the water-holding capacity of its gel. The patatinL109T gel exhibited superior elasticity and water retention properties. The findings provide valuable insight and serve as a reference for the utilisation of recombinant patatin. The established enhancement strategy could be applied to other recombinant proteins.

Probing the aggregation behavior of collagen molecules regulated by dibenzaldehyde-terminated-PEG with varying molecular weights in solution

Rigid and fragile nature of collagen-based materials cross-linked with biocompatible aldehyde-functionalized polysaccharides remains a challenge. Drawing inspiration from the pangolins' protective barrier, we introduce a novel cross-linker with a flexible chain to impart a "rigid-flexible coupled structure" to the collagen-based matrix. Successful integration of dibenzaldehyde-terminated-PEG (DF-PEG) into collagen molecules was confirmed by XRD and FTIR analyses. CD measurements demonstrated that the intact triple-helical structure was preserved in all samples. Distinct effects of DF-PEG with varying molecular weights on the aggregation behavior of collagen molecules were evaluated using multiple quantitative analysis techniques. Specifically, when the molecular weight of DF-PEG was below 20,000, multipoint hydrogen bonds and Schiff-base linkages were produced as the molecular weight of DF-PEG increased, which synergistically enhanced the aggregation behavior of collagen molecules. While the aggregation behavior of collagen molecules was slightly diminished upon the molecular weight of DF-PEG reached 20,000. This reduction can be attributed to the limited accessibility of the molecular reactive sites in the extended DF-PEG chains. Finally, a computational test of the binding interactions between collagen molecules and DF-PEG was conducted to validate the experimental results. Our biomimetic design strategy offers a new approach for the preparation of collagen-based materials with exceptional physicochemical properties.

Collagen and Its Derivatives Serving Biomedical Purposes: A Review

Biomaterials have been the subject of extensive research, and their applications in medicine and pharmacy are expanding rapidly. Collagen and its derivatives stand out as valuable biomaterials due to their high biocompatibility, biodegradability, and lack of toxicity and immunogenicity. This review comprehensively examines collagen from various sources, its extraction and processing methods, and its structural and functional properties. Preserving the native state of collagen is crucial for maintaining its beneficial characteristics. The challenges associated with chemically modifying collagen to tailor its properties for specific clinical needs are also addressed. The review discusses various collagen-based biomaterials, including solutions, hydrogels, powders, sponges, scaffolds, and thin films. These materials have broad applications in regenerative medicine, tissue engineering, drug delivery, and wound healing. Additionally, the review highlights current research trends related to collagen and its derivatives. These trends may significantly influence future developments, such as using collagen-based bioinks for 3D bioprinting or exploring new collagen nanoparticle preparation methods and drug delivery systems.

Biosynthesis of a Functional Fragment of Human Collagen II in Pichia pastoris

Collagen II (COL2) is the major component of cartilage tissue and is widely applied in pharmaceuticals, food, and cosmetics. In this study, COL fragments were extracted from human COL2 for secretory expression in Pichia pastoris. Three variants were successfully secreted by shake flask cultivation with a yield of 73.3-100.7 mg/L. The three COL2 variants were shown to self-assemble into triple-helix at 4 °C and capable of forming higher order assembly of nanofiber and hydrogel. The bioactivities of the COL2 variants were validated, showing that sample 205 exhibited the best performance for inducing fibroblast differentiation and cell migration. Meanwhile, sample 205 and 209 exhibited higher capacity for inducing in vitro blood clotting than commercial mouse COL1. To overexpress sample 205, the expression cassettes were constructed with different promoters and signal peptides, and the fermentation condition was optimized, obtaining a yield of 172 mg/L for sample 205. Fed-batch fermentation was carried out using a 5 L bioreactor, and the secretory protease Pep4 was knocked out to avoid sample degradation, finally obtaining a yield of 3.04 g/L. Here, a bioactive COL2 fragment was successfully identified and can be overexpressed in P. pastoris; the variant may become a potential biomaterial for skin care.

Recombinant fibrous protein biomaterials meet skin tissue engineering

Natural biomaterials, particularly fibrous proteins, are extensively utilized in skin tissue engineering. However, their application is impeded by batch-to-batch variance, limited chemical or physical versatility, and environmental concerns. Recent advancements in gene editing and fermentation technology have catalyzed the emergence of recombinant fibrous protein biomaterials, which are gaining traction in skin tissue engineering. The modular and highly customizable nature of recombinant synthesis enables precise control over biomaterial design, facilitating the incorporation of multiple functional motifs. Additionally, recombinant synthesis allows for a transition from animal-derived sources to microbial sources, thereby reducing endotoxin content and rendering recombinant fibrous protein biomaterials more amenable to scalable production and clinical use. In this review, we provide an overview of prevalent recombinant fibrous protein biomaterials (collagens, elastin, silk proteins and their chimeric derivatives) used in skin tissue engineering (STE) and compare them with their animal-derived counterparts. Furthermore, we discuss their applications in STE, along with the associated challenges and future prospects.

Preparation and characterization of a novel humanized collagen III with repeated fragments of Gly300-Asp329

Recombinant human collagens have attracted intensive interest in the past two decades, demonstrating considerable potential in medicine, tissue engineering, and cosmetics. Several humanized recombinant collagens have been produced, exhibiting similar characteristics as the native species. To get insight into the structural and bioactive properties of different parts of collagen, in this study, the segment of Gly300-Asp329 of type III collagen was first adopted and repeated 18 times to prepare a novel recombinant collagen (named rhCLA). RhCLA was successfully expressed in E. coli, and a convenient separation procedure was established through reasonably combining alkaline precipitation and acid precipitation, yielding crude rhCLA with a purity exceeding 90%. Additionally, a polishing purification step utilizing cation exchange chromatography was developed, achieving rhCLA purity surpassing 98% and an overall recovery of approximately 120 mg/L culture. Simultaneously, the contents of endotoxin, nucleic acids, and host proteins were reduced to extremely low levels. This fragmented type III collagen displayed a triple-helical structure and gel-forming capability at low temperatures. Distinct fibrous morphology was also observed through TEM analysis. In cell experiments, rhCLA exhibited excellent biocompatibility and cell adhesion properties. These results provide valuable insights for functional studies of type III collagen and a reference approach for the large-scale production of recombinant collagens.

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.

A highly bioactive THPC-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation

Skin aging, a complex physiological progression marked by collagen degradation, poses substantial challenges in dermatology. Recombinant collagen emerges as a potential option for skin revitalization, yet its application is constrained by difficulties in forming hydrogels. We have for the first time developed a highly bioactive Tetrakis(hydroxymethyl) phosphonium chloride (THPC)-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation. THPC demonstrated superior crosslinking efficiency compared to traditional agents such as EDC/NHS and BDDE, achieving complete recombinant collagen crosslinking at minimal concentrations and effectively inducing hydrogel formation. THPC's four reactive hydroxymethyl groups facilitate robust crosslinking with triple helical recombinant collagen, producing hydrogels with enhanced mechanical strength, excellent injectability, increased stability, and greater durability. Moreover, the hydrogel exhibited remarkable biocompatibility and bioactivity, significantly promoting the proliferation, adhesion, and migration of human foreskin fibroblast-1. In photoaged mice skin models, the THPC-crosslinked collagen hydrogel implant notably improved dermal density, skin elasticity, and reduced transepidermal water loss, creating a conducive environment for fibroblast activity and healthy collagen regeneration. Additionally, it elevated superoxide dismutase (SOD) activity and displayed substantial anti-calcification properties. The THPC-crosslinked recombinant collagen hydrogel implant presents an innovative methodology in combating skin aging, offering significant promise in dermatology and tissue engineering.

Tissue engineering applications of recombinant human collagen: a review of recent progress

With the rapid development of synthetic biology, recombinant human collagen has emerged as a cutting-edge biological material globally. Its innovative applications in the fields of material science and medicine have opened new horizons in biomedical research. Recombinant human collagen stands out as a highly promising biomaterial, playing a pivotal role in crucial areas such as wound healing, stroma regeneration, and orthopedics. However, realizing its full potential by efficiently delivering it for optimal therapeutic outcomes remains a formidable challenge. This review provides a comprehensive overview of the applications of recombinant human collagen in biomedical systems, focusing on resolving this crucial issue. Additionally, it encompasses the exploration of 3D printing technologies incorporating recombinant collagen to address some urgent clinical challenges in regenerative repair in the future. The primary aim of this review also is to spotlight the advancements in the realm of biomaterials utilizing recombinant collagen, with the intention of fostering additional innovation and making significant contributions to the enhancement of regenerative biomaterials, therapeutic methodologies, and overall patient outcomes.

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.

Development of a Pichia pastoris cell factory for efficient production of germacrene A: a precursor of β-elemene

β-Elemene, an active ingredient found in medicinal plants like turmeric and zedoary, is a sesquiterpene compound with antitumor activity against various cancers. However, its current mode of production through plant extraction suffers from low efficiency and limited natural resources. Recently, there has been an increased interest in establishing microbial cell factories to produce germacrene A, which can be converted to β-elemene by a one-step reaction in vitro. In this study, we constructed an engineered Pichia pastoris cell factory for producing germacrene A. We rerouted the fluxes towards germacrene A biosynthesis through the optimization of the linker sequences between germacrene A synthase (GAS) and farnesyl pyrophosphate synthase (ERG20), overexpression of important pathway genes (i.e., IDI1, tHMG1, and ACS), and multi-copy integration of related expression cassettes. In combination with medium optimization and bioprocess engineering, the final titer of germacrene A in a 1 L fermenter reached 1.9 g/L through fed-batch fermentation. This represents the first report on the production of germacrene A in P. pastoris and demonstrates its advantage in producing terpenoids and other value-added natural products.

Synthetic biology-guided design and biosynthesis of protein polymers for delivery

Vehicles derived from genetically engineered protein polymers have gained momentum in the field of biomedical engineering due to their unique designability, remarkable biocompatibility and excellent biodegradability. However, the design and production of these protein polymers with on-demand sequences and supramolecular architectures remain underexplored, particularly from a synthetic biology perspective. In this review, we summarize the state-of-the art strategies for constructing the highly repetitive genes encoding the protein polymers, and highlight the advanced approaches for metabolically engineering expression hosts towards high-level biosynthesis of the target protein polymers. Finally, we showcase the typical protein polymers utilized to fabricate delivery vehicles.