Abstract

QUINTERO LIZAOLA, Roberto. Microbial populations, enzyme activity and humic substances in biotransformation of waste. Terra Latinoam [online]. 2014, vol.32, n.2, pp.161-172. ISSN 2395-8030.

Microbial populations, enzyme activity and humic substances (HS) were measured during composting and vermicomposting (Eisenia andrei Bouché) oat straw with a byproduct of production of fruiting bodies of the edible mushroom Pleurotus ostreatus. Different sizes were tested: ground (< 2 mm) and chopped (< 4mm). Sampling was done 23, 46, 69, 92, 115 and 148 days after incorporating earthworms (Eisenia Andrei Bouché). Results were compared with those of treatments without worms. In each sample enzyme activity was measured for carbon cycle (amylase, cellulase, lipase and invertase), nitrogen cycle (protease, amidase, urease and nitrogenase), the phosphorus cycle (acid and alkaline phosphatase) and sulfur cycle (arylsulfatase), and dehydrogenase. Humic acid (HA) lyophilizates were assessed by analyzing and identifying color, carbon and functional groups in infrared spectroscopy using physical and chemical methods. The results showed the influence of worms on the bacteria in the treatments of chopped straw (PP) and ground straw (PM) both vermicomposted and composted. Fungi and actinomycetes were found in the highest quantities in the ground straw earthworm (PMCL) treatments. Straw size had no significant influence on the proportion of the enzymes, contrasting with the earthworm treatments, which had higher values in the sampled enzymes than those without worms. The highest concentrations of lyophilized humic acids (HA), as well as the highest concentrations of enzymes, were detected in the PMCL treatments.

Keywords : earthworms; oat straw; compost.

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