Comparative evaluation of organic and inorganic fertilizers on total phenolic, total flavonoid, antioxidant activity and cyanogenic glycosides in cassava (Manihot esculenta)

The study evaluated the effects of fertilizer sources and varieties on total phenolic, total flavonoid, antioxidant activities and cyanogenic glycosides of cassava leaves and tuber. The main factor was fertilizer sources (vermicompost, empty fruit bunch compost, NPK 15:15:15) and sub-factor was based on cassava varieties (Medan and Sri Pontian). Treatments were arranged in a split plot design with three replications. Phytochemical compounds and the antioxidant activities in young leaves and tuber were carried out after harvesting. Total phenolic and flavonoid compounds were determined by using Folin-Ciocalteu assay and aluminium chloride colorimetric method, respectively. The fertilizer sources and varieties were found to have significant effect on phytochemical compounds. Fertilizer and variety interaction was significant in total phenolics, total flavonoid, 1,1-diphenyl-2-picryl-hydrazyl (DDPH) scavenging assay and ferric reducing antioxidant capacity (FRAP) scavenging assay for tuber and leaves. The phenolic and flavonoid content was significantly higher (P<0.01) in the vermicompost treatments compared to mineral fertilizer and EFB compost. Medan had higher antioxidant activities as well as total content of phenolics and flavonoid in comparison with Sri Pontian. Organic fertilizer application resulted in significantly lower cyanide content compared to inorganic fertilizer. The results indicate that the fertilizer sources change phytochemical compounds of cassava tuber and leaves.Keywords: Manihot esculenta, cassava tuber, cassava leaves, fertilizer sources, phytochemical compounds, antioxidant activityAfrican Journal of Biotechnology Vol. 12(18), pp. 2414-242

Production and characterization of cellulases by Bacillus pumilus EB3

Cellulase production from bacteria can be an advantage as the enzyme production rate is normally higher due to bacterial high growth rate. Screening of bacteria, optimisation of fermentation conditions and selection of substrates are important for the successful production of cellulase. This study is conducted to produce cellulase from our local isolate Bacillus pumilus EB3, using carboxymethyl cellulose (CMC) as substrate. Following that, cellulase produced from Bacillus pumilus EB3 was purified using ion exchange chromatography with anion exchanger (HiTrap QXL) for characterisation of the cellulase. Cellulase was successfully produced in 2L stirred tank reactor (STR) with the productivity of 0.53, 3.08 and 1.78 U/L.h and the maximum enzyme activity of 0.011, 0.079 and 0.038 U/mL for FPase, CMCase and β-glucosidase respectively. Purification of cellulase from Bacillus pumilus EB3 using ion exchange chromatography showed that 98.7% of total CMCase was recovered. Protein separation was however based on subtractive separation where the contaminants were bound to the column instead of CMCase. Characterisation of the enzyme found that CMCase from Bacillus pumilus EB3 has a molecular weight range from 30-65 kDa and was optimally active at pH 6.0 and temperature 60℃. The CMCase also retained its activity over a wide pH range (pH 5.0–9.0) and temperature range (30-70℃).Seminar on Engineering and Technology (SET2006), September 4-5, 2006, Putrajaya, Malaysi

Diversity of fusarium species associated with post-harvest fruit rot disease of tomato

Fusarium species is one of the common pathogens of post-harvest disease to cause rot on tomato and other perishable vegetable fruits. The objectives of this study were to determine the diversity of Fusarium isolated species from post-harvest diseases of tomato fruit, to identify the causal organisms by using phenotype characteristics and to verify the pathogens of Fusarium fruit of tomato based on pathogenicity test. Carnation leaf-piece agar (CLA) and potato dextrose agar (PDA) media were used for phenotype-based identification of the Fusarium isolates with emphasis for characterizations of the shapes and sizes of the macroconidia and microconidia, colony features, growth rates, conidiogenous cells and chlamydospores. A total of 180 Fusarium isolates were obtained from 13 locations throughout Selangor. Fusarium solani was most abundantly isolated (34%) followed by F. semitectum (31%) and F. oxysporum (31%), F. subglutinans (3%) while the least was F. equiseti (1%). Twenty seven isolates were tested for pathogenicity test by injecting 1 mL of the conidial suspension onto healthy tomatoes. All the tested Fusarium isolates were pathogenic on tomato with different severity levels. The non-inoculated controls showed no symptoms of fruit rot. The most virulent was F. oxysporum isolate B711T with DSI 93.75%, while the least were isolates of F. solani (B647T) and F. oxysporum (B727T) with DSI 37.5%. Majority of the isolated Fusarium species can potentially produce mycotoxins as their secondary metabolites. The potential production of mycotoxins by pathogenic isolates of Fusarium species in contaminated tomato fruits could pose health hazards when consumed

Prospecting Agro-waste Cocktail: Supplementation for Cellulase Production by a Newly Isolated Thermophilic B. licheniformis 2D55

Bacteria isolated from thermophilic environment that can produce cellulase as well as utilise agro-waste biomass have a high potential for developing thermostable cellulase required in the biofuel industry. The cost for cellulase represents a significant challenge in converting lignocellulose to fermentable sugars for biofuel production. Among three potential bacteria examined, Bacillus licheniformis 2D55 (accession no. KT799651) was found to produce the highest cellulolytic activity (CMCase 0.33 U/mL and FPase 0.09 U/mL) at 18-24 h fermentation when grown on microcrystalline cellulose (MCC) as a carbon source in shake flask at 50 °C. Cellulase production process was further conducted on the untreated and NaOH pretreated rice straw (RS), rice husk (RH), sugarcane bagasse (BAG) and empty fruit bunch (EFB). Untreated BAG produced the highest FPase (0.160 U/mL), while the highest CMCase (0.150 U/mL) was supported on the pretreated RH. The mixture of untreated BAG and pretreated RH as agro-waste cocktail has remarkably improved CMCase (3.7- and 1.4-fold) and FPase (2.5- and 11.5-fold) compared to the untreated BAG and pretreated RH, respectively. The mechanism of cellulase production explored through SEM analysis and the location of cellulase enzymes of the isolate was also presented. Agro-waste cocktail supplementation provides an alternative method for an efficient production of cellulase