Screening, identification and characterization of lignin-degrading fungi from Sabah local biodiversity for bioconversion of oil palm waste

Abigail Lorna Eric (2023) Screening, identification and characterization of lignin-degrading fungi from Sabah local biodiversity for bioconversion of oil palm waste. Masters thesis, Universiti Malaysia Sabah.

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Abstract

Oil palm empty fruit bunch (OPEFB) is the residue that remains at the industrial sites once the crude oil palm has been extracted from the fruit bunches with approximately 22 to 23 million tons of OPEFB produced annually in Malaysia. OPEFB used to be disposed of as waste, but recently this abundantly available plant-based waste in Malaysia has been discovered as potential raw material for lignin. The biodegradation of lignin in lignocellulosic biomass has gained a lot of attention due to the eco-friendly advantages offered by this pre-treatment method compared to chemical and mechanical pre-treatments. However, studies on the biodegradation of lignin especially in OPEFB remain limited. It was hypothesized that locally isolated fungi were capable of degrading lignin in OPEFB. Hence the objectives of this study were i) to isolate and screen potential OPEFB lignin degraders, ii) to identify potential OPEFB lignin-degraders and iii) to characterize the degraded OPEFB lignin. Initially, 40 fungi portraying lignin degrading capability were isolated from decaying wood and soil samples collected from several locations in Sabah. After primary screening using Remazol Brilliant Blue R (RBBR), only seven fungi isolates exhibited positive and significant lignin-degrading results. The ligninolytic enzyme assay was conducted on the seven potential lignin-degraders to study the predominant lignin-degrading enzymes secreted by the fungi. The results revealed the capability of all seven fungi to secrete a significant amount of lignin peroxidase (LiP) enzyme when incubated in an RBBR liquid media with fungal strain 15B20 exhibiting the highest LiP production (19.81μM). The quantitative enzyme assay was followed by secondary screening incorporating Sundman and Nase assay. Three potential lignin-degraders were chosen based on the significant decolourization rate of Sundman and Nase Assay containing kraft lignin and actual OPEFB. The genomic DNAs of these potential lignin-degraders were extracted and amplified using polymerase chain reaction (PCR) and ITS1 (forward) and ITS4 (reverse) as the primers. Based on the sequence of the PCR products, fungal strains 19A23, 15B20 and 14A11 were identified as Monascus sp., Mucor sp., and Aspergillus sp. respectively. Consequently, lignin-degrader 19A23 (Monascus sp) was grown under fifteen different treatment conditions to study the effect of three parameters; the age of inoculum, weight of OPEFB and incubation time, on the OPEFB lignin degradation yield. The biological pretreatment involving seven days of inoculum age, 1.32g OPEFB and four weeks of incubation resulted in the highest degradation yield of 77.1%. In the FTIR analysis of treated OPEFB, a significant peak between 850cm-1 to 750cm-1 was detected indicating the C-H bending in the aromatic ring, which was related to the vibration of lignin.

Item Type:	Thesis (Masters)
Keyword:	Oil palm empty fruit bunch, Waste, Biodegradation
Subjects:	T Technology > TD Environmental technology. Sanitary engineering > TD1-1066 Environmental technology. Sanitary engineering > TD783-812.5 Municipal refuse. Solid wastes
Department:	INSTITUTE > Biotechnology Research Institute (BRI)
Depositing User:	DG MASNIAH AHMAD -
Date Deposited:	01 Nov 2024 09:25
Last Modified:	01 Nov 2024 09:25
URI:	https://eprints.ums.edu.my/id/eprint/41397

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