With depleting non renewable energy sources such as fossil fuels, increase in climate change and global warming, global crisis of food and water resources, the need of the hour is to find a solution. Thus scientists are constantly trying to develop eco-friendly and sustainable bioprocesses for the production of valuable bioenergy, biopolymers, biochemicals and biocompounds.
Photosynthetic microorganisms like cyanobacteria, algae, purple bacteria can serve as sustainable microbial cell factories that can produce various valuable biocompounds using economical and sustainable bioprocesses. Photosynthetic microbial cell factories as a bioproduction platform are of great interest to researchers since they use abundant and renewable non-food resources as raw materials for the synthesis of various biocompounds. Researchers from RIKEN Centre of Sustainable Resource Science (CSRS) have established one such sustainable cell factory with the help of marine photosynthetic bacteria for the production of spider silk.
According to the research team the marine photosynthetic bacterium Rhodovulum sulfidophilum was the ideal candidate for developing a sustainable cell factory. The bacterium is suitable as a green and eco-friendly bioproduction platform since it uses abundant, low-cost, renewable raw materials and resources like carbon dioxide, nitrogen and sun light for its growth and survival. The marine bacterium grows and thrives in sea water which reduces the chance of contamination during its cultivation. Rhodovulum sulfidophilum using its unique metabolic capabilities can produce biohydrogen, bioplastics and extracellular nucleic acids which make the bacteria valuable. Thus the bacterium, according to the research team has the potential to become a promising platform for synthesis of polymers, proteins and other valuable compounds.
Using these microorganisms could really help us not only in removing so much waste products, but also considerably reduce our carbon footprint, i.e. decrease levels of CO2 in the atmosphere.
Spider silk, an eco-friendly and sustainable material, is of great importance. This strong, tough, lightweight biomaterial has high tensile strength and extensibility. Hence it can be used to manufacture high performance and durable materials like tear resistant clothes, aerospace components and automobile parts.
So, there is a chance that spider silk, produced in larger quantities, could remove or at least reduce the amount od steel that we use today, especially if we consider how much coal is used today in steel mills, that is used to achieve high temperatures for iron melting.
Researchers have observed spider silk has remarkable antimicrobial properties thereby preventing the attachment of microbes on its surface. The microbe resistant property is due to the spider silk protein’s structure at the nanometre level and not because it is poisonous for cells. Based on the ability of spider silk to resist adhesion of pathogenic microbes advanced biomaterials can be developed which can eliminate the risk of biofilm formation.
These antimicrobial properties could help us in producing medical products, and in this Corona pandemic time that would be quite an important task.
Due to the fact that producing spider silk from spiders is very slow, and growing large numbers of spiders is not favorable, being the fact that spiders are highly cannibalistic and territorial, scientists have decided to use microbes to do the same job.
In an unprecedented approach the CSRS team has used Rhodovulum sulfidophilum to develop an economical and sustainable photosynthetic microbial cell factory for the production of spider silk. They genetically engineered the marine photosynthetic bacterium to produce MaSp1 protein. Under photoheterotrophic or photoautotrophic growth conditions, using small amount of organic substances, this marine purple nonsulphur bacterium was biotechnologically developed to produce the hydrophobic repetitive sequence of MaSp1. They ensured maximum output of the silk by optimizing the genetic sequence that they had inserted into the bacteria’s genome. The bacterium required a simple media consisting of bicarbonate salt, yeast extract, artificial seawater, nitrogen gas and irradiation with near infrared-light for growth and efficient expression of the silk protein. The team found that the silk fibers artificially produced by the bacteria had very similar internal structure and surface to the silk fiber produced naturally by the spiders...
NOTE: This article (text in italics) was taken as a part of the blog post Products for a sustainable future: Spider silk production from bacteria from the Bio In Our Life blog, writen by Sudhriti M. and can be read in whole on this link:
(Cover Image & Source: Host Systems for the Production of Recombinant Spider Silk @ Cell, Trends in Biotechnology)