Food waste is a mixture of organic residues that affect fermentation process. Thus, appropriate parameters should be optimised to ensure high biomethane production. In this research, response surface methodology (RSM) was utilised for building models, evaluating the significance of several independent factors (pH, temperature, substrate concentration and inocula size) and determining optimum conditions for desirable responses (biomethane yield). The RSM and contour plots set the optimum working factors in order to accomplish the desired biomethane yield. Results suggest that biomethane yield can be increased when pH and temperature are increased. Thus, the main effects of parameters are pH and temperature.
Phytochemical compounds, antioxidant and antibacterial activities of selected ethanolic aromatic Malaysian herbal extracts namely Persicaria hydropiper, Citrus hystrix, Murraya koenigii, Etlingera elatior, Cymbopogon citratus and Kaempferia galanga were screened and determined. Antioxidant activities were analysed using Ferric Reducing Antioxidant Power (FRAP), β-carotene bleaching and Oxygen Radical Absorbance Capacity (ORAC) assays. Disc diffusion assay was used to determine antibacterial activity against six bacteria strains. Alkaloids, flavonoids, saponins, tannins, terpenoids and steroids were detected in the herb extracts. P. hydropiper extract had the highest antioxidant activities in FRAP and ORAC assays in which 1676.67 mM TE/g EW and 11.20 mmol TE/g EW were obtained, respectively. However, M. koenigii extract showed 61.8% inhibition in β-carotene bleaching assay among samples but lower than BHA/BHT standard. M. koenigii extract showed the most effective antibacterial activity against three Gram-positive bacteria. Aromatic Malaysian herbs such as P. hydropiper and M. koenigii were found to exhibit high antioxidant and antibacterial activities.
Aspergillus sp. is an extremely resilient species that can be found everywhere in the environment and
is present abundantly in water and soil. The defining characteristic of Aspergillus sp. is their extensive
hyphal network which enable them to survive anywhere, even in very harsh conditions. This study was
carried out to isolate the filamentous fungi from peat soil of animal agricultural farm and characterise
them based on their morphological and molecular characteristics. Growth rate of each isolated fungi was
also evaluated in order to determine the period of maturity for each fungi. Soil samples were collected,
weighed and then dissolved in sterile distilled water. The samples were serially diluted and spread
onto potato dextrose agar (PDA) for isolation. Different isolated colonies that were morphologically
different from each plate was purified and sub-cultured onto new media for macroscopic and microscopic
identifications. For molecular identification, a conventional technique was used in genomic DNA
extraction of filamentous fungi due to their thick cell wall and presence of surface proteins protecting the
fungus. These characteristics make it difficult to harvest the genomic DNA. Polymerase chain reaction
(PCR) was carried out using internal transcribed spacer primers; ITS1 (forward) and ITS4 (reverse).
The morphological identification and molecular
technique showed that majority of these isolated
fungi are Aspergillus sp.