Cellulase production by Neurospora sitophila by employing press cake and brown juice under solid state fermentation

Sharma, Amit

4. term

Sustainable Biotechnology, Master

2019

2019-09-10

51

Dette speciale undersøger, hvordan svampen Neurospora sitophila kan udnytte andengenerations lignocellulosiske biomasse-biprodukter – pressekage og den flydende fraktion “brun juice” – til at producere enzymer, der nedbryder plantefibre. To fermenteringsformer blev sammenlignet: nedsænket fermentering (i væske) og faststof-fermentering (på fugtige faste materialer). Tre centrale cellulose-nedbrydende enzymer blev målt: FPAase, CMCase og β-glucosidase. Faststof-fermentering gav den højeste enzymaktivitet. Forsøg med sterile og ikke-sterile medier viste kraftig kontaminering i ikke-sterile opsætninger. Forskellige fortyndinger af brun juice med vand blev testet, og 5% brun juice understøttede svampens enzymproduktion. To temperaturer blev også afprøvet som led i optimeringen. I faststof-fermentering blev forskellige landbrugsrester (hvedeklid, hvedekerner og havrekerner) vurderet, og 1% hvedeklid viste sig at være den bedste inducer for højere enzymaktivitet. Tre ekstra næringsstoffer (jaggery, urinstof og sennepsolie) blev tilsat for at afklare deres rolle som inducer, men de forbedrede ikke enzymsekretionen. Efter at have optimeret nogle betingelser blev der designet en bakke-bioreaktor i laboratoriet til batchdrift baseret på faststof-fermentering, og her blev der observeret en markant stigning i enzymaktiviteten.

This thesis explores how the fungus Neurospora sitophila can use second‑generation lignocellulosic biomass by‑products—press cake and the liquid fraction known as “brown juice”—to produce enzymes that break down plant fibers. Two fermentation modes were compared: submerged fermentation (in liquid) and solid‑state fermentation (on moist solids). Three key cellulose‑degrading enzyme activities were measured: FPAase, CMCase, and β‑glucosidase. Solid‑state fermentation yielded the highest enzyme activity. Tests with sterile and non‑sterile media showed heavy contamination in non‑sterile setups. Different dilutions of brown juice with water were evaluated, and 5% brown juice supported microbial enzyme production. Two temperatures were also examined as part of the optimization. Under solid‑state conditions, various agricultural residues (wheat bran, wheat grains, and oat grains) were assessed; 1% wheat bran was most effective at inducing higher enzyme activity. Three additional nutrients (jaggery, urea, and mustard oil) were supplemented to probe their role as inducers, but they did not enhance enzyme secretion. After optimizing several conditions, a lab‑scale tray bioreactor for batch operation based on solid‑state fermentation was designed, and a notable increase in enzyme activity was observed.

[This abstract was generated with the help of AI]

Cellulase

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