Application Of Poly (3-Hydroxybutyrate-co-3-hydroxyhexanoate) In Controlled Release Fertilizer For Oil Palm Seedlings
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Date
2017-12
Authors
Paramasivam, Murugan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Polyhydroxyalkanoates (PHAs), a type of biopolymer, are synthesized by various types of bacteria under limited nitrogen source but in the presence of excess carbon source. PHAs are biodegradable and would be a suitable material to replace those non-biodegradable polymers used in controlled release fertilizer (CRF)
application. The objectives of this study were to produce poly(3-hydroxybutyrate-co-
3-hydroxyhexanoate) [P(3HB-co-3HHx)] coupled with development of biological
recovery and purification steps and finally applying the material to develop PHAbased
CRF. The biosynthesis of P(3HB-co-3HHx) was studied using feedstock
consisting of palm olein (PO) by recombinant C. necator Re2058/pCB113 using shake flask. Then, fed-batch fermentation was carried out using PO as sole carbon
source in 13 L fermenter to study the accumulation of 3HHx monomer fraction in the bacterial cells at different time point. Besides that, a biological recovery process of PHA was developed using mealworms, the larva of mealworm beetle (Tenebrio molitor). Mealworms readily consumed the freeze-dried C. necator cells and excreted PHA granules in the form of whitish feces. Further purification using water, detergent and heat resulted in almost 100% pure PHA granules when tested using gas chromatography. Comparison with chloroform extraction showed no signs of reduction in the molecular weight. The PHA granules were further subjected to a battery of tests to determine their purity and properties. The results obtained further
confirmed that the biological recovery and purification steps can be applied to extract PHA granules from bacterial cells.
Description
Keywords
Application of poly 3-hydroxybutyrate-co-3- hydroxyhexanoate , in controlled release fertilizer for oil palm seedlings