Kinetic Study of Fungal Growth of Several Tanninolytic Strains Using Coffee Pulp Procyanidins

Abstract

Procyanidins are bioactive molecules with industrial and pharmaceutical relevance, they are present in recalcitrant agro-industrial wastes that are difficult to degrade. In this study, we evaluated the potential consumption of procyanidins from Aspergillus niger and Trichoderma harzianum strains in submerged fermentations. For this purpose, a culture medium containing salts, glucose, and procyanidins was formulated, where procyanidins were added to the medium after the near-total consumption of glucose. The submerged cultures were carried out in amber flasks at 30 °C and 120 rpm. The addition of procyanidins to the culture medium increased the formation of micellar biomass for all the strains used. The use of glucose affected the growth of A. niger GH1 and A. niger HS1, however, in these assays, a total consumption of procyanidins was obtained. These results show that the consumption of procyanidins by fungal strains in submerged fermentations was influenced by the pH, the use of glucose as the first source of carbon, and the delayed addition of procyanidins to the medium. The study showed that A. niger and T. harzianum strains can be used as a natural strategy for the consumption or removal of procyanidins present in recalcitrant residues of risk to the environment and human health.

Evaluation of the Concentration of Phytotoxic Chemicals and Microbial Load of the Vermicompost Prepared from Coffee Processing Waste

“…The pre-treatment of the waste and the subsequent composting changed the scenario, leading to the increased microbial load as shown in table 16. The statistical analysis of the research revealed an increase in the content of micro-organisms in the treated soil as shown in fig 19. The vermicompost promoted the growth of microbial life and thereby making the soil aid for better agricultural manure.…”

“…The coffee husk contains some amount of caffeine and tannins, which can make it toxic and slow degradation in nature, resulting in the disposal problem. However, the coffee husk is rich in lignocellulose materials, which makes it an ideal substrate for microbial processes [19]. The disposal of these coffee processing wastes tends to be a tedious disadvantage to the soil where these coffee processing wastes are dumped due to the increased chemical content which kills the essential micro-organism naturally present in the soil.…”