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The investigation of media components for optimal metabolite production of Aspergillus terreus ATCC 20542

Abd Rahim MH, Lim EJ, Hasan H, Abbas A

J Microbiol Methods, 2019 09;164:105672.
PMID: 31326443 DOI: 10.1016/j.mimet.2019.105672

PURPOSE: This study aimed to assess the effect of nitrogen, salt and pre-culture conditions on the production of lovastatin in A. terreus ATCC 20542.
METHODS: Different combinations of nitrogen sources, salts and pre-culture combinations were applied in the fermentation media and lovastatin yield was analysed chromatographically.
RESULT: The exclusion of MnSO4 ·5H2O, CuSO4·5H2O and FeCl3·6H2O were shown to significantly improve lovastatin production (282%), while KH2PO4, MgSO4·7H2O, and NaCl and ZnSO4·7H2O were indispensable for good lovastatin production. Simple nitrogen source (ammonia) was unfavourable for morphology, growth and lovastatin production. In contrast, yeast extract (complex nitrogen source) produced the highest lovastatin yield (25.52 mg/L), while powdered soybean favoured the production of co-metabolites ((+)-geodin and sulochrin). Intermediate lactose: yeast extract (5:4) ratio produced the optimal lovastatin yield (12.33 mg/L) during pre-culture, while high (5:2) or low (5:6) lactose to yeast extract ratio produced significantly lower lovastatin yield (7.98 mg/L and 9.12 mg/L, respectively). High spore concentration, up to 107 spores/L was shown to be beneficial for lovastatin, but not for co-metabolite production, while higher spore age was shown to be beneficial for all of its metabolites.
CONCLUSION: The findings from these investigations could be used for future cultivation of A. terreus in the production of desired metabolites.

Matched MeSH terms: Microbiological Techniques/methods*
Three stage cultivation process of facultative strain of Chlorella sorokiniana for treating dairy farm effluent and lipid enhancement

Hena S, Fatihah N, Tabassum S, Ismail N

Water Res, 2015 Sep 1;80:346-56.
PMID: 26043271 DOI: 10.1016/j.watres.2015.05.001

Reserve lipids of microalgae are promising for biodiesel production. However, economically feasible and sustainable energy production from microalgae requires optimization of cultivation conditions for both biomass yield and lipid production of microalgae. Biomass yield and lipid production in microalgae are a contradictory problem because required conditions for both targets are different. Simultaneously, the mass cultivation of microalgae for biofuel production also depends extremely on the performance of the microalgae strains used. In this study a green unicellular microalgae Chlorella sorokiniana (DS6) isolated from the holding tanks of farm wastewater treatment plant using multi-step screening and acclimation procedures was found high-lipid producing facultative heterotrophic microalgae strain capable of growing on dairy farm effluent (DFE) for biodiesel feedstock and wastewater treatment. Morphological features and the phylogenetic analysis for the 18S rRNA identified the isolated strains. A novel three stage cultivation process of facultative strain of C. sorokiniana was examined for lipid production.

Matched MeSH terms: Microbiological Techniques/methods
Update on laboratory diagnosis of amoebiasis

Saidin S, Othman N, Noordin R

Eur J Clin Microbiol Infect Dis, 2019 Jan;38(1):15-38.
PMID: 30255429 DOI: 10.1007/s10096-018-3379-3

Amoebiasis, an enteric protozoan disease caused by Entamoeba histolytica, is a public health problem in many developing countries, causing up to 100,000 fatal cases annually. Detection of the pathogenic E. histolytica and its differentiation from the non-pathogenic Entamoeba spp. play a crucial role in the clinical management of patients. Laboratory diagnosis of intestinal amoebiasis in developing countries still relies on labour-intensive and insensitive methods involving staining of stool sample and microscopy. Newer and more sensitive methods include a variety of antigen detection ELISAs and rapid tests; however, their diagnostic sensitivity and specificity seem to vary between studies, and some tests do not distinguish among the Entamoeba species. Molecular detection techniques are highly sensitive and specific and isothermal amplification approaches may be developed into field-applicable tests; however, cost is still a barrier for their use as a routine laboratory test method in most endemic areas. Laboratory diagnosis of extraintestinal amoebiasis faces challenges of lack of definitive detection of current infection and commercially available point-of-care tests. For both types of amoebiasis, there is still a need for highly sensitive and specific tests that are rapid and cost-effective for use in developing countries where the disease is prevalent. In recent years, new molecules of diagnostic value are being discovered and new tests developed. The advances in 'omics' technologies are enabling discoveries of new biomarkers that may help distinguish between different infection stages.

Matched MeSH terms: Microbiological Techniques*
Fulltext Validation of wet mount microscopy against Trichomonas culture among women of reproductive age group in Western province, Sri Lanka

Banneheke H, Fernandopulle R, Gunasekara U, Barua A, Fernando N, Wickremasinghe R

Trop Biomed, 2015 Jun;32(2):192-7.
PMID: 26691246

Wet mount microscopy is the most commonly used diagnostic method for trichomoniasis in clinical diagnostic services all over the world including Sri Lanka due to its availability, simplicity and is relatively inexpensive. However, Trichomonas culture and PCR are the gold standard tests. Unfortunately, neither the culture nor PCR is available for the diagnosis of trichomoniasis in Sri Lanka. Thus, it is important to validate the wet mount microscopy as it is the only available diagnostic test and has not been validated to date in Sri Lanka. The objective was to evaluate the validity and reliability of wet mount microscopy against gold standard Trichomonas culture among clinic based population of reproductive age group women in Western province, Sri Lanka. Women attending hospital and institutional based clinics were enrolled. They were interviewed and high vaginal swabs were taken for laboratory diagnosis by culture and wet mount microscopy. There were 601 participants in the age group of 15-45 years. Wet mount microscopy showed 68% sensitivity, 100% specificity, 100% positive (PPV) and 98% negative predictive values (NPV) (P=0.001, kappa=0.803) respectively against the gold standard culture. The area under the ROC curve was 0.840. Sensitivity of wet mount microscopy is low. However it has high validity and reliability as a specific diagnostic test for trichomoniasis. If it is to be used among women of reproductive age group in Western province, Sri Lanka, a culture method could be adopted as a second test to confirm the negative wet mount for symptomatic patients.

Matched MeSH terms: Microbiological Techniques/methods*