INSTITUTO DE PROCESOS BIOTECNOLOGICOS Y QUIMICOS ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Insights of fungal solid-state fermentation for waste valorization: spore and chitinase production in different reactor configurations
ECHEGARAY, TERESA; TUBIO, GISELA; PALOMAS, GONZALO; BARRENA, RAQUEL; SALA MARTI, ARNAU; BOGGIONE, MARÍA JULIA; ARTOLA , ADRIANA
Conferencia; The 36th International Conference on Solid Waste Technology and Management; 2021
The traditional use of chemical pesticides for pest management has led to numerous problems as they are toxic both for humans and the environment. Biopesticides are considered an environmentally friendly alternative due to their harmless nature both to humans and to the environment. Among them, fungal biocontrol agents represent a promising replacement due to their effectiveness on more than 1000 species and also to their relatively inexpensive and viable mass-production process when produced by solid-state fermentation (Thakore, 2006; Sharma et al, 2014; Mascarin and Jaronski, 2016).Solid-state fermentation (SSF) allows the use of agro-industrial residues as substrates not only for fungal derivates production but also to obtain different bioproducts from a diversity of microorganisms. An extensive list of suitable substrates for fungal spore production, as well as the most used reactor configurations in fungal SSF, can be found in Sala et al (2019). This work aims to compare the suitability of two different substrates (rice husk and beer draff) for fungal spore production by solid-state fermentation using both Beauveria bassiana (BB) or Trichoderma harzianum (TH) as inoculum, basing the comparison in substrate biodegradability. In addition, two different reactor configurations were tested, being packed bed reactors (1.5L and 22L) and tray reactors. All experiments were conducted according to the optimal initial parameter values determined by Sala et al (2020), with the sole exception of temperature, which was always kept untouched due to its main effect on bioactivity (Hallsworth and Magan, 1996). Tray reactor presented values correspond to mean values of 3 trays, whereas tests in 1.5L reactors were performed in triplicates and 22L reactors were sampled at 10 different packed bed heights. Temperature values were obtained using temperature sensors, placed 2 per tray in tray reactors, one in the midst of 1.5L packed bed reactors? bed and 8 at different bed heights in 22L packed bed reactors.Spore production, mean temperature in the reactor and maximum specific oxygen uptake rate (sOUR) for all tests are presented in Figure 1. Spore productions on rice husk were lower compared to those on beer draff spore using the same configuration and strain, with the sole exception of 1.5L packed-bed reactors. This behaviour was coupled with much lower biodegradability presented by rice husk in comparison to beer draff in packed bed reactors, in which rice husk never surpassed 0.75 gO2 kg-1dm at both tested scales while beer draff varied between 2.70 to a maximum of 4.45 gO2 kg-1dm in tray reactor. Achieved mean temperature were similar between most of the reactors, presenting higher deviations in tray bioreactor than in packed bed and in beer draff than in rice husk. If comparing between strains, TH spore production has always been superior to BB?s, suggesting better use of the substrate by this fungal strain. Our results suggest a relation between spore production and biodegradability, as higher productions were obtained in beer draff reactors, even though no correlation with achieved temperature has been observed.