Application of microalgal diversity in assessing the water quality of freshwater ponds.

The health of an ecosystem can be evaluated based on its ecological characteristics and intrinsic biological quality. Furthermore, as nutrients are easily accessible by the algal cells in an aquatic ecosystem, the biochemical composition of an algal cell also varies accordingly with the ecological condition of its habitat. This study was carried out to understand the impact of seasonal variation of physicochemical parameters on the microalgal diversity and composition of five freshwater ponds in Mangalore, India. The diversity indices, viz. Shannon's (0.88-3.42), Margalef's (0.16-3.6), and Simpson's dominance index (0.47-0.96), were analyzed using PAST. A prominent variation in both the abundance and diversity of species was observed during the study period. About 150 species of algae belonging to Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae, Xanthophyceae, and Rhodophyceae were recorded. Of these groups, Chlorophyceae, specifically, desmids formed the dominant flora. Zygnematales were dominant during monsoon, while Chroococcales was the most dominant group during the post-monsoon season. Ecological conditions like temperature, pH, dissolved gases, and inorganic salts were found to impact the growth and abundance of microalgae. The ecological parameters showed a prominent effect on microalgal diversity. The results indicated that site SR was the least polluted and most diverse among the lentic habitats studied. It also had lesser noxious algal species which could be attributed to its nutrient composition.

Isolation, partial characterization and in vitro digestion of starch from Ariopsis peltata and Lagenandra toxicaria tuber.

The starch from two aroid tuber viz. Ariopsis peltata and Lagenandra toxicaria were isolated and evaluated for their morphological, physical and chemical properties. The tubers of these plants are used as food and medicine by the indigenous communities. The starch yield from A. peltata tuber was 25 ± 1.7% with an amylose content of 10 ± 0.9%, while the tuber of L. toxicaria contained 28 ± 6.5% starch with 15 ± 0.5% of apparent amylose in it. The starch isolated from both the tubers was highly pure (99%) starch exhibiting an A-type X-ray diffraction pattern. The starch granules of L. toxicaria were of various shapes and exhibited a smooth surface without any cleft or break. While the starch granules of A. peltata were spherical with smooth surface, as well as rough surface. The breaks and clefts were apparent on the rough-surfaced granules. The gelatinization temperature range for A. peltata and L. toxicaria starch is approximately 23 °C and 19 °C respectively. A. peltata starch showed higher thermal stability compared to L. toxicaria starch and either of the starch was rapidly digestible as evident from in vitro digestion study. The physicochemical properties of both the starches render them stable to withstand extreme processing. Besides they also mimic simple sugar in digestibility. So it can be utilized as a substitute for simple sugars in brewing and pharmaceutical industries.

Algal and cyanobacterial biomass as potential dye biodecolorizing material: a review.

The considerable demand for dyes worldwide has triggered a surge in their production globally. The extensive application of dyes and inefficient dyeing processes has elevated the risk of environmental pollution. The effluents from dying industries contain toxic compounds that are dreadful to both the environment and living beings. Besides, conventional effluent treatment processes have proved ineffective in clearing the dye from the effluent. The sole way of tackling this problem would be by applying a more rational approach that would be sustainable and efficient. After a thorough study of the literature, we are convinced to say that cyanophyceae and algae could serve as one of the promising biodecolorizing agents substituting most other biosorbents used in conventional biological effluent treatment technology. To evidence this we compiled data from the literature, wherein, various algal biomasses capable of decolorizing dye effluents have been examined. This paper also gives comprehensive facts on the mechanism of decolorization, pretreatment, influencing factors, and toxicity of treated products.