Penicillium commune spore production in solid‐state fermentation of coffee pulp at laboratory scale and in a helical ribbons rotating reactor

Abstract

Penicillium commune was grown on coffee pulp (CP) by solid-state fermentation (SSF). The effects of the duration of CP thermal treatment and the effects of incubation temperature on spore production yield were studied at laboratory scale. The effect of mixing during fermentation was assayed at pilot plant scale in a 70 L stainless steel non-aseptic reactor equipped with helical ribbons for mixing solids. For thermal treatments of CP at 121• C for 10, 20, 30 and 40 min, no significant difference in spore production yield was observed. Maximum sporulation yield was found at 25• C; when the incubation temperature was higher than 30 • C, the sporulation yield decreased significantly. A spore production yield of 3.7 × 10 9 spores g −1 dry CP was obtained when continuous mixing (0.25 rpm) was used at pilot plant scale; however, a decrease in spore yield (1.4 × 10 9 spores g −1 dry CP) was observed under static conditions. Spore production was not affected when a scale factor between 79 and 105 was assayed from laboratory to pilot plant; at this level, the productivity obtained was 3.1 × 10 7 spores g −1 dry CP h −1 . This value is similar to that found in other reports using natural substrates but working at a smaller scale.

Biotechnological enhancement of coffee pulp residues by solid-state fermentation with Streptomyces. Py–GC/MS analysis

“…Nowadays, several biological treatments including the use of microorganisms such as yeast, filamentous fungi and bacteria are being applied to improve the nutritional value of coffee pulp [2,3,6,7]. Although solid-state fermentation (SSF) has been used for specific biological detoxification of coffee pulp using filamentous fungi at laboratory scale [8], no data on the suitability of streptomycetes for this purpose has been reported.…”