Innocent Okonkwo Ogbonna

Isolation of microalgae species from arid environments and evaluation of their potentials for biodiesel production

Twenty-five (25) strains of microalgae were isolated and screened for growth, lipid accumulation and biodiesel production from arid environments of North East Nigeria. Isolates that produced biomass concentration (≥ 1.50 g L -1 cell dry weight), accumulated high concentrations of lipids (≥ 18% of the cell biomass) and could be purified on agar plates were selected for further studies. Four strains morphologically identified as Oocystis IA1, Chlorella IA7, Chlorococcum KA9 and Botyrococcus YA5 were selected. The maximum biomass concentrations (g L -1 ) and lipid contents (%) were 3.02, 3.92, 3.59 and 2.89, and 57, 67.23, 63 and 65 dry cell weights for Oocystis IA1, Chlorella IA7, Chlorococcum KA9 and Botyrococcus YA5, respectively. The highest oil productivities (mg L -1 day -1 ) were 135.28 ± 3.32 ( Oocystis IA1), 165.22 ± 3.36 ( Chlorella IA7), 131.76 ± 1.11 ( Chlorococcum KA9) and 140.37 ± 2.13 ( Botyrococcus YA5). Maximum chlorophyll contents (g g -1 cell) were 34.97, 30.00, 39.71 and 32.27, respectively. Fatty acid methyl ester profiles indicated the presence of C16:0, C16:1, C18:0, C18:1, and C18:2. Oleic acid (C18: 1) was predominant, ranging between 73.3 and 85.6%. Biodiesel properties were within the ASTM standards. The present study suggested that the four isolates are good for biodiesel production. Keywords: Biodiesel, Chlorella , Chlorococcum , Botyrococcus sp., lipid accumulation, microalgae, Oocystis . Abbreviation: FAME, Fatty acids methyl esters.

Characterization of moulds associated with processed garri stored for 40 days at ambient temperature in Makurdi, Nigeria

Characterization of moulds associated with processed white and yellow garri stored at ambient temperature for 40 days was investigated. The moulds isolated from white garri (%) were: Aspergillus spp 35.3, Penicillium spp 23.53, Fusarium spp 2.94, Mucor spp 17.65, Alternaria spp 5.88, Cladosporium sp 2.94 and Rhizopus 11.76%. For yellow garri: Aspergillus spp 37.04, Penicillium spp 23.53, Fusarium spp 7.41, Mucor spp 18.52, Rhizopus spp 14.81, Alternaria spp 0% Cladosporium sp. and Aspergillus spp had the highest frequency of occurrence in both white and yellow garri. Higher moulds species were isolated from white garri (34) compared to yellow (27) samples. The mean total fungal counts from the three hostels were 6.22 × 10 3 , 7.22 × 10 4 and 9.67 × 10 5 CFUg -1 in white garri, and 3.56 × 10 3 , 4.22 × 10 4 and 5.78 × 10 5 CFUg -1 in yellow garri. There were significant differences in total mean fungal counts in the various dilutions of white and yellow garri at p < 0.05. Results also revealed that the longer the storage time, the higher the pH and moisture content. Proper storage is recommended owing to the public health concern due to mycotoxins, food safety, shelf life and biostability of this product. Keywords: Garri, moulds, storage, pH, moisture content African Journal of Biotechnology , Vol. 13(5), pp. 673-677, 29 January, 2014

Evaluation of Oil Producing Potential of a New Isolate— Chlorella lewinii SUB3545914 for Biodiesel Production under Heterotrophic Cultivation

Microalgae with high oil productivities are most desired in biodiesel production. Chlorella lewinii SUB3545914, was isolated and assessed for its growth rates, lipid productivities and fatty acid profiles under heterotrophic cultivation. The alga was isolated after enrichment in BG-11 medium (pH = 7.3) under a light intensity of approximately 17.5 μE·m-2·s-1 at 30°C ± 2°C. In addition to morphology, polymerase chain reaction (PCR) and metagenomics were used for isolate identification. The DNA was sequenced and multiple sequence alignment of the BLASTED results revealed 95% similarity to Chlorella lewinii. Maximum growth (3.15 ± 0.06 g·L-1), lipid content (44.0%) and lipid volumetric productivities (118.80 ± 3.02 mg·L-1·day-1) in glucose supplemented media were more appreciable in comparison with the glycerol counterparts. Similarly, the highest growth (2.03 ± 0.68 g·L-1), lipid content (31.47%) and lipid productivities (47.21 ± 2.08 mg·L-1·day-1) in glycerol supplemented media were more than those got under autotrophic cultivation. Chlorophyll contents did not vary remarkably in heterotrophic cultures. The major fatty acids obtained by Gas Chromatography Mass Spectrometry (GC-MS) were oleic and Octadecanoic acids for all the culture conditions. Chlorella lewinii is appropriate for accumulating lipids for biodiesel under heterotrophic cultivation on glucose because of high lipid volumetric productivities.

Effect of formaldehyde antimicrobial feed additive on the immune competence of chickens experimentally infected with a known Newcastle disease virus strain

Thirty-seven percent (37%) formaldehyde- possessing antimicrobial activity has been used in various forms as a fumigant for mould control and as a feed additive for feed preservation. The study evaluated the effects of formaldehyde-treated poultry feed on the immune response of birds to Newcastle disease virus (NDV) infection with Kudu 113 strain. A total of 100 chicks were acquired from Zartech Hatchery, Ibadan, Nigeria. They were randomly appropriated into A, B, C and D experimental groups, with each group containing 25 birds. Group A chicks were vaccinated, fed treated feed and infected with ND virus while group B chicks were vaccinated, fed untreated feed and infected with ND virus. Chicks in group C were not vaccinated but fed treated feed and infected with ND virus whereas chicks in group D were not vaccinated, fed untreated feed and infected with ND virus. The data generated were analysed with analysis of variance (ANOVA). Formaldehyde-treated feed had no significant effect on the PCV, antibody response to NDV, organ index and feed intake but significantly affected the body weights of the birds. Formaldehyde, despite the antimicrobial activities, may not prevent infection of Newcastle disease virus infection, when used as a feed additive.