Research-intership with mini-study on parametric measuring of polyhydroxyalkanoate (PHA) yield using rice bran as substrate

Date

2025

Adviser

Abriel S. Bulasag

Principal

Mabel S. Buela

Abstract

Polyhydroxyalkanoates (PHAs) are biodegradable polymers recognized as promising alternatives to conventional plastics derived from fossil fuels. However, the high production cost remains a challenge. To address this, the use of agricultural waste as a low-cost substrate has gained significant traction in recent years. In the Philippines—an agro-industrial nation with abundant agricultural byproducts—rice bran presents a viable yet underutilized resource for PHA production. The study evaluated the potential of rice bran hydrolysate as a substrate for PHA synthesis using Cupriavidus necator (KCTC 2649), a PHA-producing bacterial strain. To determine the optimal pretreatment conditions, a 2k factorial design experiment was conducted to assess the effects of acid concentration and incubation time on total reducing sugar (TRS) yield. The ideal condition—0.1 N sulfuric acid for 22 minutes—yielded a predicted TRS concentration of 12.083 g/L, with only a 0.644% error from experimental validation. Using these optimized parameters, three fermentation setups (RB1, RB2, and RB3) were designed to compare PHA yield, productivity, and TRS consumption. Among the three setups, RB1 demonstrated the most favorable conditions, achieving the highest PHA yield (21.718 g/L) and the lowest TRS consumption (1.522 g/L), indicating high productivity with minimal substrate use. RB2 showed the highest TRS consumption (7.880 g/L) but resulted in the lowest PHA yield (12.343 g/L), suggesting lower conversion efficiency. RB3, meanwhile, consumed 3.736 g/L of TRS and produced a moderate PHA yield of 15.419 g/L, reflecting a more efficient sugar-to-PHA conversion than RB2, though still less optimal overall compared to RB1. These findings show the potential of rice bran as an efficient, low-cost substrate for PHA production, supporting its integration into sustainable bioplastic development. Future research is encouraged to investigate a wider range of acid hydrolysis parameters and explore other locally available agricultural wastes to further improve PHA yield and support cost-effective bioplastic production in the Philippines.

Language

English

Notes

To access this capstone, please contact the UP Rural High School Library at uprhslibrary.uplb@up.edu.ph. You may also visit the library in person, provided you secure prior confirmation from the librarian. We will be happy to assist you.

Document Type

Capstone

This document is currently not available here.

Share

COinS