Betty Mbatia

Improved utilization of fish waste by anaerobic digestion following omega-3 fatty acids extraction

Fish waste is a potentially valuable resource from which high-value products can be obtained. Anaerobic digestion of the original fish waste and the fish sludge remaining after enzymatic pre-treatment to extract fish oil and fish protein hydrolysate was evaluated regarding the potential for methane production. The results showed high biodegradability of both fish sludge and fish waste, giving specific methane yields of 742 and 828 m(3)CH(4)/tons VS added, respectively. However, chemical analysis showed high concentrations of light metals which, together with high fat and protein contents, could be inhibitory to methanogenic bacteria. The feasibility of co-digesting the fish sludge with a carbohydrate-rich residue from crop production was thus investigated, and a full-scale process outlined for converting odorous fish waste to useful products.

Enzymatic Synthesis of Lipophilic Rutin and Vanillyl Esters from Fish Byproducts.

Lipase-catalyzed synthesis of lipophilic phenolic antioxidants was carried out with a concentrate of n-3 polyunsaturated fatty acids (PUFAs), recovered from oil extracted from salmon ( Salmon salar ) byproduct. Vanillyl alcohol and rutin were selected for the esterification reaction, and obtained esters yields were 60 and 30%, respectively. The antioxidant activities of the esters were compared with those of commercial butylated hydroxytoluene (BHT) and α-tocopherol using DPPH radical scavenging and thiobarbituric acid assays. In the DPPH assay, rutin esters showed better activity than vanillyl esters, and on the contrary in lipophilic medium, vanillyl esters were found to be superior to rutin esters. In bulk oil system, the antioxidant activities of rutin and vanillyl derivatives were lower than that of BHT and α-tocopherol, but in emulsion, they showed better activity than α-tocopherol. By attaching to natural phenolics, the PUFAs are protected against oxidation, and PUFA improves the hydrophobicity of the phenolic, which could enhance its function in lipid systems.

Screening and Characterization of Hydrocarbonoclastic Bacteria Isolated from Oil-contaminated Soils from Auto Garages

Release of petroleum oil and its products into the environment is a worldwide concern. The present study focused on isolation, molecular identification, morphological and biochemical characterization of bacteria possessing hydrocarbon-degrading properties. The study also aimed at optimizing appropriate culture conditions for the isolates as well as screening for alkane hydroxylase enzyme. Out of twenty one microbes isolated, nine were selected based on their ability to utilize different hydrocarbons. The isolates were observed to mineralize heating oil, hexane, octane, toluene and diesel oil. PCR amplification of 16S rDNA gene revealed that the isolates belong to six different genera; Pseudomonas, Acinetobacter, Klebsiella, Enterobacter, Salmonella and Ochrobactrum. Based on their ability to degrade diesel oil, three isolates were selected and their growth conditions optimized. Optimum degradation was recorded at less than 1% substrate concentration, pH 7 and temperature range of between 30°C and 37°C and using yeast extract as nitrogen source. GC-MS analyses confirmed their diesel oil degrading properties. Alkane hydroxylase gene from one of the isolates (isolate 1C) was successfully amplified indicating its catabolic capabilities in degrading alkanes. Overall, the characterized isolates may constitute potential candidates for biotechnological application in environmental cleanup of petroleum contaminants.

Comparative Analysis of Phytochemical Composition and Antioxidant Activities of Methanolic Extracts of Leaves, Roots and Bark of Jackfruit (Artocapus heterophyllus) from Selected Regions in Kenya and Uganda

Aim: To determine and compare the phytochemical composition and antioxidant activities of methanolic extracts of Jackfruit roots, leaves and bark, found in selected regions of Kenya and Uganda. Study Design: A total of 192 samples of leaves, roots and barks, were obtained from 64 different Original Research Article Ojwang et al.; JABB, 16(1): 1-13, 2017; Article no.JABB.37355 2 Jackfruit trees. The samples were then dried and extracted using methanol. Place and Duration of Study: The study was carried out at The University of Nairobi, Chiromo campus, Department of Biochemistry in Nairobi, Kenya. The research was carried out from May 2016 to June 2017. Methodology: The composition of phenolic and tannin contents were determined using FolinCiocalteu method. Flavonoids content was determined through the formation of the flavonoids– aluminium complex assay. Antioxidant activity was determined through the DPPH scavenging activity and the reducing power of the extracts. Results: The phytochemical composition had significant variation at (P=.05) in all the different parts of the plant. The roots had the highest phenolic content (67.3759.00 mg/g), while the bark region had the least (38.14 -28.34 mg/g). The flavonoid content was also highest in the roots (10.74 7.31 mg/g) and lowest in the bark region (3.09 – 1.49 mg/g). The tannin contents were equally higher in the roots (3.88 2.69 mg/g), and lowest in bark (0.93 -0.52 mg/g). The DPPH scavenging activity was also highest in the roots (66 -72%), while that of the bark was (24 40%). The reducing power of the roots, leaves and bark ranged from (114.38 – 93.62 μg/ml), (71.63 -67.04 μg/ml) and (54.16 33.15 μg/ml) respectively. Conclusion: The findings suggest that Jackfruit roots, leaves and bark are natural antioxidants and they have significant variation in composition of phytochemical compounds.