Effect of Chlorella vulgaris as a biofertilizer on germination of tomato and cucumber seeds

Although inorganic fertilizers are known to raise environmental and health problems, the current agricultural practices are heavily dependent on the application of synthetic fertilizers and pesticides. In this study, we examined the effect of Chlorella vulgaris strain on germination of tomato and cucumber seeds. Seeds were germinated in culture medium containing algal strain and grown for 3, 6, 9 and 12 days to study its effect on growth parameters. As results, C. vulgaris suspension increased the seed growth compared to those of the control (sterilized culture medium) of seed germination. The best treatments were 0.17 and 0.25 g/L of algal suspension for the root and shoot lengths of tomato and cucumber seeds, respectively

Effects of culture conditions on biomass and pigment accumulations of three Chlorella species

Mass cultivation of microalgae for high value co-products is one of the developing fields in algal biotechnology. However, the accumulation of desired co-products such as pigments under optimum culture condition is often too low to be economically feasible. One of the approaches to counteract this problem is the use of stress conditions. The success of this strategy depends on an adequate understanding of the biosynthesis pattern and the functional roles of pigments in response to individual stress condition. The aim of this thesis study was to conduct a comprehensive literature review on pigment analysis in algae and to investigate the effects of different culture conditions on biomass and pigment accumulations of three Chlorella species. Prior to investigating the effects of culture conditions, we developed reliable methods for algal pigment analysis using HPLC and LC-MS instruments on the basis of extensive literature review. These methods were used to analyze all the data obtained in this study. When the species were grown in Kuhl, Bold's Basal and modified Chu-10 media, the highest contents of biomass and pigment were attained in Kuhl medium. Furthermore, when the cultures were grown under different pH ranges (7.0--10.0), the results v showed that C. vulgaris and C. pyrenoidosa could withstand a higher pH (8.0 or higher) and produce higher contents of biomass and pigments at alkaline pH than at neutral pH level. However, neutral pH (5.8 to 7.0) conditions were suitable for the growth and pigment accumulation of C. sorokiniana. These results suggested that C. vulgaris and C. pyrenoidosa are alkaline-tolerant strains and are suitable candidates for the outdoor cultivation without pH regulation. Moreover, these features are also economically beneficial for harvesting and anticontamination systems in large-scale production