Fruit preservation with bioethanol obtained from the fermentation of brewer’s spent grain with Saccharomyces carlsbergensis
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Date
2020-08-30
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Abstract
Brewer’s Spent Grain (BSG) is renewable lignocellulosic biomass generated from the beer brewing
process. It serves as a substrate for various biotechnological applications. BSG was used as the main
substrate for bioethanol production with Saccharomyces carlsbergensis in submerged fermentation.
Saccharification and fermentation studies were performed for the production of bioethanol. A sterilized
fermenter was loaded with 50 g L-1 of BSG at 29±2 °C and an agitation speed of 180 rpm. pH was
adjusted to 6.0 before the addition of 500 mL of yeast culture for 7 days under submerged and optimized
conditions. The fermented product was concentrated using a rotary evaporator at 66±1 °C, and ethanol
was qualitatively determined by the dichromate method. Bioethanol yield was 22%, with a specific
gravity of 0.8 at 28 °C. Fourier-Transform Infrared Spectroscopy (FTIR) confirmed the presence of -CH3 stretch
, -OH stretch and -CH2stretch in bioethanol. For the preservative test, Staphylococcus spp., Erwinia
spp., Lactobacillus spp., Bacillus spp., Xanthomonas spp., Pseudomonas spp., Micrococcus spp.
and Corynebacterium spp. were the bacteria isolated from fruits examined from different regions of
Osun State. The genera of fungi isolated were Aspergillus, Colletotrichum, Penicillium, Fusarium,
Alternaria, Rhizopus, Candida, Saccharomyces, Geotrichium and Pichia. Bioethanol produced from
BSG inhibited the growth of microorganisms with zones of inhibition range from 7.0 mm to 11.5 mm,
and thus, selected fruits were preserved. Hence, the fermentation technology of agro-industrial wastes
with microorganisms can be adopted to convert waste biomass to useful resources