Potential Of Solid-state Fermentation Research Articles

Production of cell-wall degrading enzymes by solid-state fermentation using agroindustrial residues as substrates

This study is focused in the production of cell-wall degrading enzymes (chitinase, β-1,3-glucanase, endocellulase and exocellulase) by solid state fermentation using the fungus Metarhizium anisopliae IBCB 348. Different substrates (sugarcane bagasse, malt bagasse and white rice) supplemented with corn steep liquor, soybean meal and chitin were evaluated. A Plackett-Burman experimental design was applied to evaluate the effects of initial moisture content (60–80%, v/v), corn steep liquor (0–5%, w/w), soybean meal (0–5%, w/w) and inoculum concentration (10–30%, v/w) on enzymatic production. Sugarcane bagasse was the most suitable substrate for enzyme production, mainly chitinase. Maximum activities were 12.07 ± 0.50, 11.54 ± 6.96, 20.87 ± 0.43 and 22.30 ± 0.41 U.g−1 for chitinase, β-1,3-glucanase, endocellulase and exocellulase, respectively. The process condition used to obtain these activities were moisture content of 40 wt%, 10% (v/w) of inoculum, 28 °C during 8 days of fermentation. These results demonstrate the potential of solid state fermentation using Metarhizium anisopliae IBCB 348 in the production of hydrolytic enzymes.

Solid state fermentation for the production of γ-decalactones by Yarrowia lipolytica

Abstract The production of γ-decalactones as aroma compounds is highly dependent on the access of the biocatalyst to substrate and co-substrate (oxygen). In this work, the potential of solid state fermentation (SSF) is investigated for this production with Y. lipolytica W29. Luffa sponge was used as an inert support and the investigation focused on the impact of aeration on metabolites. In that goal, experiments were carried out in three different SSF reactor types, wide-mouth Erlenmeyer flask (static aeration), forced aeration mini-reactor, and small-headspace bottle (without aeration). Four lactones were detected by GC–MS during the degradation of ricinoleic acid from castor oil by Y. lipolytica W29: 3-hydroxy-γ-decalactone, which reached the high concentration of 5 g/L (in wide-mouth Erlenmeyer flask), γ-decalactone, dec-2-en-4-olide and dec-3-en-4-olide. In this study, some yeast cells changed their morphological properties from the yeast-like shape to pseudo-mycelium and mycelium. These cells may undergo a metabolic shift resulting in the high production of 3-hydroxy-γ-decalactone. The yield of lactone in the small-headspace bottle was very low suggesting insufficient oxygen availability. For their part, forced-aeration conditions in mini-reactors resulted in the stripping of lactone compounds. From the present work, an alternative process is proposed as a novel model for lactone production.

Enrichment of Mung Bean with L-DOPA, GABA, Essential Amino Acids via Controlled Biofermentation Strategy

L-DOPA (L-3,4-dihydroxyphenylalanine) the precursor of neurotransmitter dopamine is used in the management of Parkinson disease and effective in controlling diabetic state. Gamma-aminobutyric acid (GABA), a non-protein amino acid is known to have many pharmacological functions and plays a major role in inhibiting neurotransmitter in brain. Whereas essential amino acids can’t synthesize in human body and it must be taken from foods to maintain good immune function. This study aims to evaluate the enrichment of mung bean with L-DOPA, GABA and essential amino acids via controlled solid state fermentation using Rhizopus strain 5351. Fermentation was carried out for a duration up to 48 h at 30 °C and the samples were analyzed at certain time intervals. The concentration of glucosamine and I²-glucosidase, which indicated the growth of fungal was noted low at the early growth stage (0 to 10 h), but it was observing increased linearly within 18 to 48 h growth periods. The L-DOPA was produced after 10 h fermentation time (0.008 g/100 g dry weight, DW) and the highest yield of L-DOPA content (0.07 g/100 g DW) was attained at the fermentation time of 28 h. However, the concentration of L-DOPA was noted decreased after that. The protease activity, free and essential amino acids content also showed a drastic increment within the fermentation period of 10 to 38 h. The highest content of free and essential amino acids (FAAs and EAAs) and the protease activity of fermented mung bean were exhibited at 38 h incubation time, which were 3.74 g/100 g DW, 1.43 g/100 g DW and 18.4 U/g dry weight, respectively. The GABA content of fermented mung bean was found low (0.019 - 0.021 g/100 g DW) at early incubation time (0-10 h), however, it showed a drastic increment in the fermented mung bean after 18 h (0.132 g/100 g DW) and continuously increased until 38 h (0.198 g/100 g DW). This study showed the potential of solid state fermentation as a good strategy to enrich the fermented mung bean with L-DOPA, GABA and other beneficial bioactive compounds which play an important role to maintain good health as it helps to enhance our immune system and regulating neurotransmitter function.

Fungal bioleaching of metals in preservative-treated wood

Twenty-four brown-rot and 10 white-rot fungi were screened to evaluate their applicability for detoxification of preservative-treated wood impregnated with copper and chromium (CC) salts. Brown-rot fungi generally showed higher tolerance towards copper inhibition than white-rot fungi. Additionally, brown-rot fungi were found to accumulate considerable quantities of oxalic acid (up to 44.3 mM) in liquid medium, while white-rot fungi generally accumulated only traces of this organic acid. Oxalic acid is a strong organic acid capable of complexing a variety of heavy metals. Four Antrodia vaillantii and two Poria placenta brown-rot strains that displayed both a high copper tolerance and a high oxalic acid production were selected for further study. The brown-rot fungi effectively decayed wood containing up to 4.4% CC causing corrected mass losses of up to 24.3% in 4 weeks. Fungal treatment was also found to promote extensive leaching of chromium (up to 52.4%), but only moderate leaching of copper (15.6% or less). These results indicate the potential of solid-state fermentation with copper-tolerant fungi for the remediation of preservative-treated wood. Improving the solubility of copper will be an important challenge for future research.

Potential of solid state fermentation for production of L(+)-lactic acid by Rhizopus oryzae

Potential of solid state fermentation for production of L(+)-lactic acid by Rhizopus oryzae

Potential of solid state fermentation for production of L(+)-lactic acid by Rhizopus oryzae

Production of l(+)-lactic acid by Rhizopus oryzae NRRL 395 was studied in solid medium on sugar-cane bagasse impregnated with a nutrient solution containing glucose and CaCO3. A comparative study was undertaken in submerged and solid-state cultures. The optimal concentrations in glucose were 120 g/l in liquid culture and 180 g/l in solid-state fermentation corresponding to production of l(+)-lactic acid of 93.8 and 137.0 g/l, respectively. The productivity was 1.38 g/l per hour in liquid medium and 1.43 g/l per hour in solid medium. However, the fermentation yield was about 77% whatever the medium. These figures are significant for l(+)-lactic acid production.

Potential of solid state fermentation for production of ergot alkaloids.

Production of total ergot alkaloids by Claviceps fusiformis in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of Claviceps purpurea but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids.