Pusat Pengajian Sains Kajihayat - Tesis

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Biosynthesis And Optimization Of P(3hb-Co-3hv-Co-4hb) Terpolymer Using Glycerine Pitch As Carbon Source
(2024-11)
Ibn, Abbas Musa
Conventional plastics have become an essential commodity that provides comfort through their applications in the packaging, medical, agricultural, and pharmaceutical industries. However, traditional plastic is recalcitrant to microbial degradation. Bioplastics like polyhydroxyalkanoates (phas) are biodegradable and biocompatible materials that have proven to be an alternative to synthetic plastics. One of the significant problems of pha biosynthesis is the cost of carbon sources, which accounts for about 40% of production costs. The use of major food-grade oils is uneconomical and unsustainable as it may limit the availability of cooking oil and trigger an increase in the price of edible oil, leading to food-feed competition. Therefore, glycerine pitch produced pha in cupriavidus malaysiensis usmaa1020 via single-stage cultivation and optimized in a 13 l bioreactor. Two other monomers were incorporated by the addition of 1,4 butanediol and 1-pentanol, resulting in the synthesis of a terpolymer consisting of 3hb, 3hv and 4hb monomers [p(3hb-co-3hv-co-4hb)]. Effects of different concentrations of glycerine pitch, 1-pentanol, 1,4 butanediol, and oleic acid were studied.
Effect Of Soil And Microbiota Composition In Black Morel Continuous And Non-Continuous Cultures
(2024-11)
Zhang, Yan
The black morel Morchella sextelata (Morchellaceae, Pezizales) is a valuable edible mushroom cultivated on a large scale, but severe yield decline occurs during continuous cropping. The effects of long-term cropping on soil properties, microbiome imbalances, and their impact on morel yield remain unclear. To help fill this knowledge gap, this study employed an indoor experiment to assess how cropping regimes affect soil properties, microbial communities, and morel production. This study assessed the impact of non-continuous cropping (NCC) and continuous cropping (CC) systems at three developing stages of M. sextelata development (bulk soil, conidial, and primordial stage) by using rDNA metabarcoding and network analysis. CC significantly reduced morel primordia yield in the third year compared to NCC, with the former showing a 99.7% reduction. The results showed that during the first year, M. sextelata mycelium overwhelmed the resident soil fungal community by reducing the alpha diversity and niche breadth of soil fungal patterns to a greater content compared to the continuous cropping regime, leading to high crop yield, but less complex soil mycobiome. To sustain continuous cropping, exogenous nutrition bags and morel mycelial spawn were consecutively added to the soil. The additional nutrient input stimulated the growth of fungal saprotrophic decomposers.
Population Ecology Of Fiddler Crabs (Ocypodidae: Gelasiminae) In The Mangroves Of Penang Island, Malaysia
(2024-10)
Zolkhiflee, Nurhafiza
Little is known about the population ecology of fiddler crab in northern peninsular malaysia, and as such, a study on the population ecology of this species was conducted in mangroves of penang island for 12 months from march 2017 to february 2018. Monthly sampling was conducted to collect the fiddler crab, sediment sample and physicochemical parameter data. This study investigates the abundance, growth patterns, and feeding habits of fiddler crabs in the mangrove ecosystems of penang island, focusing on the influence of environmental parameters, microhabitat variations, and seasonal changes. The distribution and abundance of fiddler crabs were analysed in relation to environmental factors. Austruca annulipes and gelasimus vocans were predominantly found in coarser, well-lit mudflat habitats, while tubuca rosea, tubuca forcipata, and sp. 1 were associated with finer, organic-rich sediments. Seasonal variations played a significant role, with species like t. Rosea maintaining a strong preference for finer sediments across seasons. The significant three-way interaction between site, microhabitat, and season highlights the complex dynamics influencing fiddler crab habitats as such for a. Annulipes that show significantly higher abundance in pulau betong mudflat during wet season. These findings highlight the importance of physicochemical variables, such as sediment composition and light intensity, in shaping fiddler crab populations.
Comparison Of Starch Content And Transcriptomes Of Felled Oil Palm Trunks At 0 And 15 Days Of Storage
(2004-10)
Hasri, Nur Hanis Alisa Md
The oil palm trees are logged for replantation after they reach their maximum productivity of palm oil production. Massive biomass waste such as the oil palm trunk (opt) is generated during the replanting process. The opt biomass residues have been reported to contain a high amount of starch and sugar (glucose, sucrose, and fructose) that have high potential for various industrial uses (e.G., in value-added products). However, low starch opts with no use and practicality have also been identified in the oil palm plantations. In this study, high-starch and low-starch opt were firstly felled and further stored for 15 days. A storage period of 15 days was used as 15 days is a sufficient period to transport the opts from the plantation and to deliver to industrial companies for further applications. More specifically, the top and middle parts of the trunks containing sugar and starch, on the day the trees were felled (day 0 of storage) and 15 days later (day 15 of storage) were examined. Within the storage period, the starch and sugar contents were identified and the transcriptomes of the felled opt were sequenced to distinguish the high and low-starch opt. During the 15 days of storage, the starch content slightly decreased while the sugar content slightly increased in all the opts.
Characterization Of Aerophytic Oxyphototrophs Isolated From Gua Tempurung, Malaysia: Polyphasic And Biochemical Approaches
(2024-03)
Abdullahi, Zulaihat Hamza
Caves are among the extreme oligotrophic environments with limited nutrients and low light intensity, but some aerophytic microalgae find this environment suitable for their growth and survival. Gua Tempurung is the largest limestone caves in Malaysia, but unfortunately no study was conducted on its algal diversity, taxonomic information, adaptation, physiological, and biochemical composition. This study aimed to assess the characteristics and adaptation of aerophytic oxyphototrophs isolated from Gua Tempurung.

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