77Tanakarn MONSHUPANEECheewanun Dachoupakan SIRISOMBOON78Increased bioplastic production in divergent photosynthetic microalgae: An efficient conversion of solar energy and carbon dioxide to bioplastic by Calothrix scytonemicola TISTR 8095(Project 2014)Early Detection of Ochratoxigenic Fungi on Green Coffee Beans by Near Infrared Spectroscopy(Project 2014)Poly(3-hydroxybutyrate) (PHB) is the thermostable and biodegradable plastic exhibiting material properties comparable to the petrochemical plastic polypropylene. PHB is also compatible to various human tissues, thus was used as artificial scaffold for tissue engineering. Approximate two-dozen species of photosynthetic microalgae in a group of cyanobacteria have been reported previously for the ability to produce PHB from abundant atmospheric CO2 and light energy as the sole substrates. In this study, the cellular PHB content was determined in 137 strains of cyanobacteria representing 88 species in 26 genera under six nutrient conditions. The 134 strains (86 species) were found to be PHB producers. The PHB contents of these 134 strains were subtle under normal nutrient condition, but were significantly increased in 63 strains under nitrogen-limited condition (–N), a higher frequency than with other nutrient conditions. A high level of PHB production was not associated with any particular evolutionary groups, but was strain specific. The filamentous algae Calothrix scytonemicola TISTR 8095 produced PHB at 356.5 ± 63.4 mg / liter of culture, under –N from a biomass of 1396.6 ± 66.1 mg / liter of culture, giving a PHB content of 25.4 ± 3.5% (PHB weight / cell dry weight). This PHB productivity is equivalent to the CO2 consumption of 729.2 ± 129.8 mg / liter of culture. The maximum energy conversion from solar energy to be stored in PHB obtained by C. scytonemicola TISTR 8095 was 1.42 ± 0.30%.Ochratoxin A (OTA) is a mycotoxin, produced by filamentous fungi, toxic to humans and animals and found in a wide range of different foods and agricultural products including green coffee beans. The early detection of ochratoxigenic fungi in green coffee beans at the beginning of the process is important for the elimination of OTA contamination. This research focuses on the possibilities to use near infrared spectroscopy (NIRS) for the detection of ochratoxigenic Aspergillus contamination in green coffee beans. The NIR spectral data and percentage of total fungal infection were obtained from 116 green coffee bean samples. Quantitative calibration models to detect the percentage of fungal infection were developed using the original and pretreated absorbance spectra in conjunction with partial least square regression (PLSR). The best model for predicting total fungal contamination was developed from the range normalization pretreated spectra with the correlation coefficient (r) of 0.835, standard error of prediction (SEP) and bias of 15.205%, and 0.718%, respectively. The best model for predicting Aspergillus section Nigri contamination was developed from the multiplicative scatter correction pretreated spectra (r = 0.865, SEP = 19.051%, bias = -1.478%). The best model for predicting Aspergillus section Circumdati contamination was developed from the second derivative by Savitzky-Golay method of 21 points pretreated spectra (r = 0.972, SEP = 7.704%, bias = 0.351%). For qualitative models, the classification model of Aspergillus section Circumdati contamination in green coffee bean samples developed using partial least square-discriminant analysis (PLS-DA) provided the highest percentage of overall correct classification of 100%. Results showed that NIRS technique had a great potential for the detection of ochratoxigenic fungal contamination in green coffee beans.64
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