Eco-friendly Agarose Choices for Gel Electrophoresis
Is there such a thing as eco-friendly laboratory agarose? When you consider the chemistry involved in the manufacturing of this laboratory staple the answer is yes!
The agarose you use to pour a gel in the lab originates from the global agar industry which is undergoing a sustainability transformation. In itself agarose is a renewable and biodegradable material. Harvesters and manufacturers are successfully cooperating to improve how red seaweed is harvested and used to extract agar for food and fertilizer. That’s a good thing for marine ecosystems!
Many additional steps purify agarose from agar for use in gel electrophoresis. The agarose extraction and purification methods confer gel properties to pair well with samples, stains, buffers, and electric fields for successful runs. The final product is made up of linear, repeating units of agarbiose that aggregate and bundle as fibers to form a transparent gel when mixed in aqueous buffer, heated, and allowed to cool.
The performance bar is set high for manufacturers of electrophoresis quality agarose. To be useful for applications like restriction enzyme digests, gel shift assays, or DNA footprinting the agarose must be DNase and RNase-free.The gel needs to physically hold together at low concentration. Critically, the lower the sulfate in agarose, the higher the gel strength which is noted by the force required in g/cm2 to fracture a gel of standard percent concentration. The gel must flow in a way that minimizes the diffusion of nucleic acid samples as the negatively charged molecules move toward the positive electrode at different rates according to their molecular weight. That’s why electroendosmosis - how water flows through the gel in an electric field - is another key performance factor. Lower electroendosmosis (EEO) agarose gels improve DNA or RNA resolution. The bands are tighter. There are also protocols when the agarose gel must have a low melting point. For example, a low melting gel can resolve higher molecular weight DNA. Or it can be used to add an enzyme directly to remelted agarose to purify nucleic acids directly from your gel. Agarose manufacturers usualy apply hydroxyethylation to produce agarose with lower melting temperatures. Agarose is manufactured with variations of these core properties for different purposes in electrophoresis. In every case, these performance standards must be maintained in industrial-scale agarose extraction and purification methods.
Green chemistry improves agarose sustainability
There are significant differences in the sustainability of various agarose production methods. Conventional agarose production methods meet these challenges but with high environmental costs. The production process employs harmful organic reagents, high energy use, and high volumes of liquid waste. Alternative agarose production methods have been developed for some time. Examples include incorporating organic solvent recycling or applying enzymatic desulfation for extraction. It’s tricky. The extraction step separating agarose from sulfated galactan in agar is critical to agarose quality and overall process costs. Unfortunately, each alternate method reported in the literature has shown lower yields which can make manufacturing costs higher.
Happily, a few laboratory vendors have still scaled up greener methods for commercial agarose production!
Environmentally friendly choices:
TopVision™ Agarose tablets - Manufactured using a proprietary process that eliminates the use of organic solvents.
HyAgarose™ and InstantAgarose™ - Available for routine use, low melting point, and high-resolution PCR-grade. Manufactured without the use of organic solvents.
CleverGEL - Available for routine use, low melting point, and high-resolution PCR-grade. Manufacturing excludes organic solves harmful to marine life.
The future of this wonderfully useful biopolymer looks even brighter. Marine biologists and chemists are improving methods to achieve higher yields. One promising report addresses sustainable production in the extraction step that separates agarose from sulfated glycan.Yield is more than doubled compared with extraction methods that use DEAE-cellulose, Polyethylene glycol (PEG) or EDTA-anion exchange resin. See: Cong Zhang et al. Convenient Agarose Preparation with Hydrogen Peroxide and Desulfation Process Analysis (2021) Marine Drugs. Perhaps agarose production will become even greener sooner!