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The biodegradation and mineralisation of hexadecane (HXD) by Aspergillus niger were studied in SmF and Solid-state fermentation (SSF). HXD concentrations ranging from 45 to 180 g/l (SSF) and from 20 to 80 g/l (SmF) were tested. HXD consumption was three times higher and fungal growth was up to 30 times faster in SSF than in SmF. The maximum HXD consumption in SmF was 62% (18% mineralised) and in SSF 100% (52% mineralised) for initial HXD concentrations of 20 and 45 g/l, respectively. The respiratory quotient in SmF increased (from 0.85 to 1.08) with increase in HXD concentration, while it was independent (approximately 0.68) of the initial HXD concentration in SSF. These results showed that the consumption rate and biodegradation efficiency for HXD were higher in SSF than in SmF.

The growth of Pleurotus ostreatus was analyzed on three particle sizes of sugar cane bagasse: 0.92 mm and 1.68 mm in diameter, in addition to heterogeneous fibers (average 2.9 mm in diameter). Specific growth rate on heterogeneous particles was lower (μ=0.043 h(-1)), although soluble protein production was maximal (809 μg/g dry wt). Higher μ values were reached on the other two particles sizes (0.049-0.05 h(-1)) with less soluble protein (500 μg/g dry wt). Xylanases and laccases were favored in heterogeneous particles; while the highest selectivity for xylanases over cellulases was observed in 1.68 mm particles, corresponding with the maximal hemicellulose breakdown. Lignin and cellulose were preferentially degraded in smallest particles. This study shows that the geometrical ratio, shape and size of sugar cane bagasse fibers strongly influence packing density for SSF substrate, with an impact in the production of extracellular enzymes, growth rates and composition changes in substrate.