Application of Sargassum sp. for the production of vermicompost using the earthworm, Eisenia foetida (Californian red worm)

Abstract

Vermicomposting is one of the technologies used for the biotransformation of different types of organic wastes. The most used substrates are household waste and green area waste. Recently, it has been found in the literature that seaweed is being used as a carbon source in vermicomposting. Therefore, in the present study, samples of sargassum (Sargassum spp.) that arrive on the coasts of the Mexican Caribbean and that represent an environmental, social, and economic problem were biodegraded. The objective was to obtain a biofertilizer or biosoil improver. The sargassum was collected on the beaches of Cancún, Quintana Roo, Mexico. It was moved to a laboratory located in the state of Veracruz, 1,340 km away. From the total batch of 25 kg on a wet basis, a sample of 1.2 kg was separated for identification. The rest decomposed by spontaneous biodegradation^[1] and the degraded material was enriched with an inoculum of plant origin (1:5 m/m) and, finally, used as a substrate for vermiculture with Eisenia foetida. The sargassum species identified were Sargassum natans and Sargassum fluitans. A vermicompost was obtained that meets most of the values established in the standard for vermicompost of organic waste. It should be mentioned that this standard does not consider sargassum as a substrate. The vermicompost obtained was used as a biofertilizer/biosoil improver for three crops: Coriander (Coriandrum sativum), red basil (Ocimum basilicum L.) and purple skunk epazote (Chenopodium glaucum), obtaining greater plant growth compared to controls without vermicompost during the experiment. It can be concluded that the use of vermicomposting and its use in the cultivation of three edible herbs was successful.

^[1] Fermentation is a bioreaction that involves glucose with Saccharomyces cerevisiae under anaerobic conditions to produce ethyl alcohol and carbon dioxide and was designated by that name by Louis Pasteur, so no other bioreaction should not carry such name [Editors' note]