Before agar, microbiologists had experimented with other foodstuffs as microbial media. They turned to substances rich in the starches, proteins, sugars, fats, and minerals that organisms need for growth, testing with broths, bread, potatoes, polenta, egg whites, coagulated blood serums, and gelatine. However, none worked particularly well: all were easily broken down by heat and microbial enzymes, and their surface, once colonized, became mushy and unsuitable for isolating microbes.
In some cases, alternative gelling agents might provide faster results. Researchers observed that bacterial cellulose and another bacterial polysaccharide, Eladium, allow a 50 percent increased growth rate for various bacteria and yeasts (as compared to their growth on agar), including higher biomass yields or faster detectable biofilm formation. However, both substances are still not as cheap and readily available as agar.
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