Study on coffee husk treatment by microorganisms

Abstract

The aim of this study was to identify the biodegradation abilities of some indigenous microorganisms applied in coffee husk treatment into organic substrates. There were three useful strains in coffee husks that were isolated and identified as Bacillus thuringiensis CF₂, Bacillus subtilis CF_4, and 01 fungal strain Cladosporium tenuissimum CF₁₇. The biodegradation diversity of organic compounds in coffee husks as well as nitrogen fixation and 3- Indol acetic acid (IAA) production of those strains were tested. The biomass of three strains also were collected from fermentation broth and mixed into biomass solution with 1:1:1 (v/v/v) proportion in volume and then were incubated with dry coffee husks. The results showed that the most effective incubation formula is mixing 500 mL of the biomass solution mixture with 20 kg of dry coffee husks for 8 weeks. The quality of the substrates from coffee husk waste after 08 weeks of incubation is shown through a number of indicators meeting the quality of organic substrates specified in TCVN 7185: 2002 and testing the quality of the substrates. The organic substrates from coffee husks were used to grow sprouts and accessed. The weight of sprouts obtained when sowing on coffee husk substrates reached 69.7 grams while it reached 43.2 grams on a commercial substrate in the same area of 30 cm².