Jan Hilary A. Alcanzo, Pette Bernard T. Rose, Marielle J. Yap (February 2007)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Using bacterial plastics is known to be more efficient and effective than recycling and using landfills. Plastics that are commonly used today are petroleum-based, making them resistant to biodegradation.
PHB or polyhydroxybutyrate is a bacterial plastic synthesized by Lactobacillas casei No study has yet been done on the effect of various glucose concentrations on PHB production of L.casei at different incubation periods.
This study investigated the amount of PHB produced when Lactobacillus casei was cultured in MRS broth with 0%, 25%, 50%, 75%, and 100% excess of glucose at 48, 60, and 72- hour incubation periods. PHB crystals were extracted using the chloroform extraction method, and the amount of PHB was measured at 235 nm through a spectrophotometer.
The amount of PHB produced by Lactobacillus casei cultured in MRS broth with various glucose concentrations and duration of incubation ranged from 1.6327-34116 ppm.
Statistical analysis (One-Way ANOVA and Fisher’s LSD) showed that the Lactobacillus casei cultured at MRS broth with 50% glucose concentration produced significantly higher amount of PHB than the L. casei cultured with other glucose concentrations (p=0.016, a=0 05). Results further showed that the L. casei incubated at 48-hour period produced significantly higher amounts of PHB than the other incubation periods (p=0.007, -0.05) Highest amount of PHB can be obtained when L.casei is cultured in MRS broth with 50% increase in glucose incubated for 48 hours.