Fed-batch Protein Enrichment of Cassava by Solid-state Fermentation: Optimization of Process Conditions and Preliminary Economic Feasibility Study

Author : Villaverde, Julianita A.
Major Adviser : Chay, Pham Binh
Committee Members : Acda, Reynaldo I.; Movillon, Jovita A. 
Year : 1993
Month : April
Type : Thesis
Degree: BS
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the optimum conditions for he protein enrichment of cassava based on the data gathered by Lat (1990) were established. By multiple linear regression analysis, an equation was developed realating the protein yield to various parameters (pH, biomass concentration, feed amount, substrate layer thickness, fermentation time and time of feeding). The regression equation developed is as follows:

Y = -32.0315 – 2.4889 X₁ + 0.8934 X₃ + 303137 X₄ – 0.5892 X₅ + 0.1068 X₂ + 0.6543 X₆

where: Y = total protein yield (g/100 g dry matter)
X₁ = pH
X₂ = fermentation time (hr)
X₃ = biomass concentration (w/w db)
X₄ = feed amount (%)
X₅ = substrate layer * thickness (cm)
X₆ = time of withdrawal of fermented substrate and subsequent addition of fresh medium (hr)

The maximum protein yield obtained was 30.6761and 35.8025 g/100 g dry matter for initial and final harvesting, respectively. An economical evaluation of the process was also pursued. However, it is not economical to operate at maximum protein yield because the ROI is 56.71 %. Sensitivity analysis showed that (1) as increase in the price of protein from ₱ 0.030 to ₱ 0.055 and (2) a reduction of 75 % and 50 % on raw material and labor cost, respectively would give an ROI of 23.02 %, hence, economically feasible for investment. This is on the basis of 29.8807 and 35.0071 g total protein/100 g dry matter production.

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