Theses & Dissertations

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https://hdl.handle.net/20.500.14170/194

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Browsing Theses & Dissertations by Subject "Agricultural waste"
  • Publication
    Characterization of different types of spent mushroom substrate (SMS) for African catfish (Clarias Gariepinus) diet suitability
    ( 2016)
    Nur Aziera Abd Rasib
    Spent Mushroom substrate (SMS) is one of agricultural wastes produced by thever expending mushroom industries in Malaysia. Chemically, it is rich in organic matter which potentially can be utilized for aquaculture. Utilization of SMS as fish feed has never been conducted before as very limited information on SMS biochemical composition is available. Regarding to this matter, new formulation of fish feed was developed by incorporating SMS and other ingredients namely soybean waste, fish meal, topioca flour and rice bran. Commanly, different types of SMS that being cultivated at six to seven cycles were collected which identified as white oyster (Pleuratos ostreatus), grey oyster (Pleuratos sajor-caju), abalone (Pleuratos cystidiosus), ganoderma (Ganoderma lucidium) and black jelly (Auricularia polytricha). Those SMS were tested on their biochemical composition which involving the analysis of crude protein, carbohydrate, fat, lignin and ash. Overall trend showed an increment in crude protein and fat content, whereas carbohydrate and lignin showed a reduction in the content. Ganoderma attained the highest protein value, 36.6 g, followed by black jelly, white oyster, grey oyster and abalone. Contradictory, lowest carbohydrate reduction was observed in ganoderma at 70.42 g and the most was in black jelly. Increment in fat and reduction in lignin showed almost similar value for each SMS. The highest (ganoderma), medium (white oyster) and lowest (abalone) protein content were the basis of SMS types selection to be incorporated in pellet formulation using Pearson square method which emphasized on the protein and energy. The ingredients were mixed and a pelletalization was carried out after 40 minutes of steaming process at 80° C. A series of physical properties test of SMS pellets were conducted to confirm the applicability of the formulated pellet for fish consumption by comparing with commercial fish feed.
  • Publication
    Citric acid leaching process for silica extracted from oil palm ash for zeolite synthesis
    ( 2017)
    Faizul Che Pa
    Agricultural wastes such as oil palm ash have a possibility to be utilized as a useful renewable source for production of energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes, due to silica as a useful raw material for industrial application. Oil palm ash is one of the waste material from the palm oil industry where is was obtained from the burning process of solid waste such as empty fruit bunch, shell and fiber. Oil palm ash contains a large amount of silica. This study has been conducted to extract silica from palm ash by removing impurities using citric acid via leaching process. Various experimental parameters, such as acid concentration (1 to 6 %), reaction time (30 to 180 minutes), leaching temperature (30 to 90 C) and solid/liquid ratio (1:50 – 1:10) were investigated. Then, the effect of each parameter towards extraction process was evaluated using XRF, FTIR, XRD and SEM. The optimum extracting condition was achieved at 3% concentration of citric acid, 70C of solution temperature, 60 minutes of reaction time and 1:25 ratio of solid/liquid. XRF results show that the content of silica in treated palm ash can reach up to 92% after citric acid leaching treatment. The transmittance peaks at 798 - 778 cm-1 show that silica element is absent in the treated palm ash. Preliminary tests have shown that there is a possibility of using silica extracted from palm ash to synthesize zeolite.
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  • Publication
    Optimization of Sodium Hydroxide pretreatment and enzymatic saccharification of spent rubberwood sawdust for glucose production
    ( 2014)
    Siti Aminah Mohd Hassan
    Large quantities of oyster mushroom spent medium (MSM) were disposed of as agricultural waste to the environment and thereby constituting environmental pollution. Economic reuse of the waste mushroom medium to produce glucose might be a viable solution instead of disposal. Therefore, the study was conducted to improve the added value of mushroom spent medium as an alternative glucose source to the current expensive sugar crops and starchy products. Firstly, the chemical characteristics, surface morphology, and suitability of mushroom spent medium in comparison to rubber sawdust (RSD) and growth medium (GM) were examined in order to investigate its potential as a new glucose feedstock. The composition analysis proved that decreases in lignocellulosic contents occurred after cultivation of Pleurotus sajor caju. The amount of lignin, hemicelluloses, and cellulose in MSM showed lower values than those in RSD and GM which were 22.40, 27.93, and 27.97% respectively. The surface morphology of MSM appeared to be rough and broken and traces of hyphen on the fibre surface were observed as a result from the mushroom cultivation process. RSD and FM had an even and smooth flat surface, indicating a rigid and highly ordered surface structure. Preliminary study on effectiveness and feasibility of the three pretreatment techniques (autoclaving at 121°C, heating in water bath, soaking at room temperature) with different NaOH concentration on RSD, GM, and MSM revealed the best result of 30.13 g glucose/100g dry substrate and 33.50% of hydrolysis weight decrease obtained from MSM, which had been treated in water bath at 90°C for 2 h. The scanning electron microscope (SEM) images of the corresponding MSM hydrolysate showed severe disruptions of biomass structure, irregular cracks, and pores. One factor at a time (OFAT) method was applied to screen the range of parameters in NaOH pretreatment via heating in water bath and enzymatic saccharification. With known parameters’ range, the Response surface methodology (RSM) based on Box-Behnken Design (BBD) was adopted to optimize the conditions of NaOH pretreatment via heating in water bath method and enzymatic saccharification of MSM. The optimum conditions of MSM pretreatment at substrate loading of 5.0% (w/v) were found to be NaOH concentration of 2.63 M, reaction temperature of 92.26°C, and treatment time of 112.92 min with maximum glucose yield of 34.55 g/100g dry substrate after 48 h of enzymatic saccharification at constant enzyme loading of 67 FPU/g dry substrate and substrate loading of 1.0% (w/v). The MSM hydrolysate obtained under optimal NaOH pretreatment conditions were further used to optimize enzymatic saccharification conditions at constant substrate loading of 1.0% (w/v). Under optimized conditions (agitation rate of 150.74 rpm, enzyme loading of 94.92 FPU/g substrate, and hydrolysis time of 56.89 h), a maximum glucose yield of 71.21 g/100 g dry substrate was achieved. The Analysis of Variance (ANOVA) test revealed that the model and all independent parameters were considered statistically significant at 95% for both optimization studies using the second order polynomial equation. The model validation showed a good agreement between experimental results and the predicted responses. Therefore the models could be successfully used to identify the effective combinations of the three different factors in both optimization studies for predicting the glucose yield from MSM.
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