Microbial cell factories for the production of polyhydroxyalkanoates

2021 ◽  
Author(s):  
Dillirani Nagarajan ◽  
Ganies Riza Aristya ◽  
Yu-Ju Lin ◽  
Jui-Jen Chang ◽  
Hong-Wei Yen ◽  
...  

Abstract Pollution caused by persistent petro-plastics is the most pressing problem currently, with 8 million tons of plastic waste dumped annually in the oceans. Plastic waste management is not systematized in many countries, because it is laborious and expensive with secondary pollution hazards. Bioplastics, synthesized by microorganisms, are viable alternatives to petrochemical-based thermoplastics due to their biodegradable nature. Polyhydroxyalkanoates (PHAs) are a structurally and functionally diverse group of storage polymers synthesized by many microorganisms, including bacteria and Archaea. Some of the most important PHA accumulating bacteria include Cupriavidus necator, Burkholderia sacchari, Pseudomonas sp., Bacillus sp., recombinant Escherichia coli, and certain halophilic extremophiles. PHAs are synthesized by specialized PHA polymerases with assorted monomers derived from the cellular metabolite pool. In the natural cycle of cellular growth, PHAs are depolymerized by the native host for carbon and energy. The presence of these microbial PHA depolymerases in natural niches is responsible for the degradation of bioplastics. Polyhydroxybutyrate (PHB) is the most common PHA with desirable thermoplastic-like properties. PHAs have widespread applications in various industries including biomedicine, fine chemicals production, drug delivery, packaging, and agriculture. This review provides the updated knowledge on the metabolic pathways for PHAs synthesis in bacteria, and the major microbial hosts for PHAs production. Yeasts are presented as a potential candidate for industrial PHAs production, with their high amenability to genetic engineering and the availability of industrial-scale technology. The major bottlenecks in the commercialization of PHAs as an alternative for plastics and future perspectives are also critically discussed.

Author(s):  
Stefano Bertacchi ◽  
Stefania Pagliari ◽  
Chiara Cantù ◽  
Ilaria Bruni ◽  
Massimo Labra ◽  
...  

In the context of the global need to move towards circular economies, microbial cell factories can be employed thanks to their ability to use side-stream biomasses from the agro-industrial sector to obtain additional products. The valorization of residues allows for better and complete use of natural resources and, at the same time, for the avoidance of waste management to address our needs. In this work, we focused our attention on the microbial valorization of cinnamon waste material after polyphenol extraction (C-PEW) (Cinnamomum verum J.Presl), generally discarded without any additional processing. The sugars embedded in C-PEW were released by enzymatic hydrolysis, more compatible than acid hydrolysis with the subsequent microbial cultivation. We demonstrated that the yeast Rhodosporidium toruloides was able to grow and produce up to 2.00 (±0.23) mg/L of carotenoids in the resulting hydrolysate as a sole carbon and nitrogen source despite the presence of antimicrobial compounds typical of cinnamon. To further extend the potential of our finding, we tested other fungal cell factories for growth on the same media. Overall, these results are opening the possibility to develop separate hydrolysis and fermentation (SHF) bioprocesses based on C-PEW and microbial biotransformation to obtain high-value molecules.


2021 ◽  
Vol 11 (12) ◽  
pp. 5352
Author(s):  
Ana Margarida Pereira ◽  
Diana Gomes ◽  
André da Costa ◽  
Simoni Campos Dias ◽  
Margarida Casal ◽  
...  

Antibacterial resistance is a major worldwide threat due to the increasing number of infections caused by antibiotic-resistant bacteria with medical devices being a major source of these infections. This suggests the need for new antimicrobial biomaterial designs able to withstand the increasing pressure of antimicrobial resistance. Recombinant protein polymers (rPPs) are an emerging class of nature-inspired biopolymers with unique chemical, physical and biological properties. These polymers can be functionalized with antimicrobial molecules utilizing recombinant DNA technology and then produced in microbial cell factories. In this work, we report the functionalization of rPBPs based on elastin and silk-elastin with different antimicrobial peptides (AMPs). These polymers were produced in Escherichia coli, successfully purified by employing non-chromatographic processes, and used for the production of free-standing films. The antimicrobial activity of the materials was evaluated against Gram-positive and Gram-negative bacteria, and results showed that the polymers demonstrated antimicrobial activity, pointing out the potential of these biopolymers for the development of new advanced antimicrobial materials.


Fuel ◽  
2021 ◽  
Vol 298 ◽  
pp. 120858
Author(s):  
Sana Malik ◽  
Ayesha Shahid ◽  
Chen-Guang Liu ◽  
Aqib Zafar Khan ◽  
Muhammad Zohaib Nawaz ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Zhenyu Zhang ◽  
Pengfu Liu ◽  
Weike Su ◽  
Huawei Zhang ◽  
Wenqian Xu ◽  
...  

AbstractTrans-4-hydroxy-l-proline is an important amino acid that is widely used in medicinal and industrial applications, particularly as a valuable chiral building block for the organic synthesis of pharmaceuticals. Traditionally, trans-4-hydroxy-l-proline is produced by the acidic hydrolysis of collagen, but this process has serious drawbacks, such as low productivity, a complex process and heavy environmental pollution. Presently, trans-4-hydroxy-l-proline is mainly produced via fermentative production by microorganisms. Some recently published advances in metabolic engineering have been used to effectively construct microbial cell factories that have improved the trans-4-hydroxy-l-proline biosynthetic pathway. To probe the potential of microorganisms for trans-4-hydroxy-l-proline production, new strategies and tools must be proposed. In this review, we provide a comprehensive understanding of trans-4-hydroxy-l-proline, including its biosynthetic pathway, proline hydroxylases and production by metabolic engineering, with a focus on improving its production.


2012 ◽  
Vol 29 ◽  
pp. S75-S76
Author(s):  
Mhairi Workman ◽  
Philippe Holt ◽  
Xiaoying Liu

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