The Correlation between Lipase Activity and the Production of Fatty Acids of PBC Cocoa Clone

A study was carried out to determine the correlation between lipase activity in cocoa beans and the presence of free fatty acids which could affect the aroma and flavour of cocoa. Lipase activity fell from 0.46 to 0.15 ~mol/min/mg protein during six days of fermentation. Changes in the pH from 6.6 to 5.1 in the cotyledon and the increase in temperature seems to have contributed to the decrease in lipase activity, although no consistent correlation was observed. Maximum acetic acid production was observed on the third day of fermentation, when the maximum temperature was attained by the cocoa beans. However, other fatty acids increased continuously until the fifth day of fermentation and declined thereafter

Isolation and characterization of an acrylamide-degrading yeast Rhodotorula sp. strain MBH23 KCTC 11960BP

As well as for chemical and environmental reasons, acrylamide is widely used in many industrial applications. Due to its carcinogenicity and toxicity, its discharge into the environment causes adverse effects on humans and ecology alike. In this study, a novel acrylamide-degrading yeast has been isolated. The isolate was identified as Rhodotorula sp. strain MBH23 using ITS rRNA analysis. The results showed that the best carbon source for growth was glucose at 1.0% (w/v). The optimum acrylamide concentration, being a nitrogen source for cellular growth, was at 500 mg l–1. The highest tolerable concentration of acrylamide was 1500 mg l–1 whereas growth was completely inhibited at 2000 mg l–1. At 500 mg l–1, the strain MBH completely degraded acrylamide on day 5. Acrylic acid as a metabolite was detected in the media. Strain MBH23 grew well between pH 6.0 and 8.0 and between 27 and 30 °C. Amides such as 2-chloroacetamide, methacrylamide, nicotinamide, acrylamide, acetamide, and propionamide supported growth. Toxic heavy metals such as mercury, chromium, and cadmium inhibited growth on acrylamide

Isolation, identification and characterization of elevated phenol degrading Acinetobactersp. Strain AQ5NOL 1

The increasing phenol and phenolic wastes necessitates the screening of bacteria that are able to degrade phenol. 115 bacterial isolates from several industrial sites and farms in Malaysia were screened for phenol degrading activity in minimal salt media (MSM) containing 0.5 gL-1 phenol. Thirty seven bacterial isolates exhibited phenol degrading activity and of this total, 6 isolates showed high phenol activity after 8 days of incubation. The isolate with the highest phenol degrading activity was subsequently identified as Acinetobacter sp. Strain AQ5NOL 1 based on BiologTM GN plates and partial 16S rDNA molecular phylogeny. The optimum conditions for achieving high phenol degradation were 0.04% (w/v) (NH4)2SO4, 0.01% (w/v) NaCl, pH 7, and temperature of 30°C. Acinetobacter sp. Strain AQ5NOL 1 was found to degrade phenol of up to 1500 mgL-1 concentrations under the optimized conditions. The isolation of Acinetobacter sp Strain AQ5NOL 1 provides an alternative for the bioremediation of phenol and phenolic wastes

A simple method to screen for azo-dye-degrading bacteria

A stab-culture method was adapted to screen for azo dyes-decolorizing bacteria from soil and water samples. Decolorized azo dye in the lower portion of the solid media indicates the presence of anaerobic azo dyes-decolorizing bacteria, while aerobic decolorizing bacteria decolorizes the surface portion of the solid media. Of twenty soil samples tested, one soil sample shows positive results for the decolourisation of two azo dyes; Biebrich scarlet (BS) and Direct blue 71 (DB) under anaerobic conditions. A gram negative and oxidase negative bacterial isolate was found to be the principal azo dyes degrader The isolate was identified by using the Biolog identification system as Serratia marcescens

Biological Remediation of Cyanide: A Review

Cyanide and its complexes are produced by industries all over the world as waste or effluents. Biodegradation is considered to be the cheapest and the most effective method to get rid of cyanide in the environment. Several studies on different types of microorganisms that can degrade cyanide in the environment have been carried out. Hydrolytic, oxidative, reductive, and substitutive/transfer reactions are some of the common pathways used by microorganisms in cyanide degradation. Biodegradation of cyanide can occur aerobically or an-aerobically depending on the environmental conditions. Immobilised enzymes or microorganisms prove to be very effective method of degradation. Microorganisms such as Klebsiella oxytoca, Corynebacterium nitrophilous, Brevibacterium nitrophilous, Bacillus spp., Pseudomonas spp. and Rhodococcus UKMP-5M have been reported to be very effective in biodegradation of cyanide

ISOLATION AND CHARACTERIZATION OF AN ACRYLAMIDE-DEGRADING Burkholderia sp. STRAIN DR.Y27

 ABSTRACT Several local bacteria have been isolated from glyphosate-contaminated soils at various locations throughout Malaysia. Quantitative monitoring of acrylamide degradation was performed using High Performance Liquid Chromatography (HPLC) whilst bacterial growth was carried out by plate counting. The isolate was tentatively identified as Burkholderia sp. strain DR.Y27 based on carbon utilization profiles using Biolog GN plates and partial 16s rDNA molecular phylogeny. Highest growth was obtained at acrylamide concentrations of between 100 to 2000 mg L-1.  Complete degradation of 850 mg L-1 of acrylamide occurs after ten days of incubation with concomitant cell growth. The isolate grew optimally in between pH 6.0 and 8.0. The effect of incubation temperature on the growth of this isolate shows an optimum growth at 30°C. Glucose, lactose, maltose, fructose, mannitol, citric acid and sucrose at an initial concentration of 1.0% (w/v) supported growth with glucose being the best carbon source. Aliphatic amides such as 2-chloroacetamide, methacrylamide, nicotinamide, acrylamide, acetamide, propionamide and urea supported growth with increasing assimilative capability from 2-chloroacetamide to urea. The characteristics of this isolate suggest that it would be useful in the bioremediation of acrylamide.  Keywords:  isolation, characterization, acrylamide-degrading, Bacteriu

Characterization of a diesel-degrading strain isolated from a hydrocarbon-contaminated site

A diesel-degrading bacterium has been isolated from a diesel-polluted site. The isolate was tentatively identified as Staphylococcus aureus strain DRY11 based on partial 16S rDNA molecular phylogeny and Biolog® GP microplate panels and Microlog® database. Isolate 11 showed an almost linear increase in cellular growth with respect to diesel concentrations with optimum growth occurring at 4% (v/v) diesel concentration. Optimization studies using different nitrogen sources showed that the best nitrogen source was potassium nitrite. Sodium nitrite was optimum at 1.2 g l-1 and higher concentrations were strongly inhibitory to cellular growth. The optimal pH that supported growth of the bacterium was between 7.5 to 8.0 and the isolate exhibited optimal broad temperature supporting growth on diesel from 27 to 37 °C. An almost complete removal of diesel components was seen from the reduction in hydrocarbon peaks observed using Solid Phase Microextraction Gas Chromatography analysis after 5 days of incubation. The characteristics of this bacterium suggest that it is suitable for bioremediation of diesel spills and pollutions in the tropics

Hexavalent molybdenum reduction to mo-blue by acinetobacter calcoaceticus

A local molybdenum-reducing bacterium was isolated and tentatively identified as Acinetobacter calcoaceticus strain Dr.Y12 based on carbon utilization profiles using Biolog GN plates and 16S rDNA comparative analysis. Molybdate reduction was optimized under conditions of low dissolved oxygen (37 degrees C and pH 6.5). Of the electron donors tested, glucose, fructose, maltose and sucrose supported molybdate reduction after 1 d of incubation, glucose and fructose supporting the highest Mo-blue production. Optimum Mo-blue production was reached at 20 mmol/L molybdate and 5 mmol/L phosphate; increasing the phosphate concentrations inhibited the production. An increase in an overall absorption profiles, especially at peak maximum at 865 nm and the shoulder at 700 nm, was observed in direct correlation with the increased in Mo-blue amounts. Metal ions, such as chromium, cadmium, copper, mercury and lead (2 mmol/L final concentration) caused approximately 88, 53, 80, 100, and 20 % inhibition, respectively. Respiratory inhibitors, such as antimycin A, rotenone, sodium azide and cyanide showed in this bacterium no inhibition of the Mo-blue production, suggesting that the electron transport system is not a site of molybdate reduction