Quality analysis of commercial Chlorella products used as dietary supplement in human nutrition

Abstract

Chlorella vulgaris is one of the best-studied phototrophic eukaryotes. From the 1950s on, C. vulgaris and some other algal species were cultivated in huge quantities to meet the growing demand for alternative protein sources. After drying, algal biomass can be merchandised as tablets, capsules, extract or powder with specific biochemical qualities. However, the products quality, e.g. the containing species, microbial contamination or content and quality of pigments varies enormously. In this study, commercial Chlorella products, unprocessed Chlorella powders and several production strains were investigated. Molecular analysis of the 18S rDNA confirmed either the existence of more than one species per product or only other green algae species in about half of the samples tested. Many of the examined samples contained critical amounts of bacterial contaminations. Furthermore, cyanobacteria were detected in some of the samples. The content of chlorophyll a varied greatly between the samples and pheophytin, a degradation product of chlorophyll, was detected in some samples in large concentrations. These data indicate that quality control of microalgal products is an important issue that should be addressed by the manufactures.

An investigation of Clostridium species present in nutraceutical preparations of Arthrospira platensis (Spirulina) for human consumption

“…It was recently suggested that the aseptic culture of microalgal biomass in industrial quantities is "impossible" and that classic culture techniques underestimate numbers of microbial contaminants. In addition, the presence of recalcitrant endospores in the processed biomass was highlighted as a concern (Görs et al 2010). Results presented here suggest the same for A. platensis bulk culture.…”

Integration of Chlorella protothecoides production in wastewater treatment plant: From lab measurements to process design

“…These experiments were carried out in vertical batch bubbling reactors of 250 mL of volume, illuminated with artificial continuous light (100 μmol m −2 s −1 ) and mixed by aeration enriched with CO 2 (5% v/v). Native microflora contamination was controlled by a non-specific plate counting method, as described in [24], by counting the CFU (colony forming units) of a sample of a given volume in LB medium. Petri plates were incubated at 37°C and the count was performed after 24 h.…”

The Potential for ‘Next-Generation’, Microalgae-Based Feed Ingredients for Salmonid Aquaculture in Context of the Blue Revolution

“…Lessons could be learned from the relatively niche, poorly regulated natural health food market for microalgae such as Chlorella. Görs et al [4] reported that quality control is poor for almost all Chlorella-based products on the global marketplace. For example, most are contaminated with bacteria, cyanobacteria and other unlisted algal species, contain highly variable levels of chlorophyll and/or its breakdown products and were greatly heterogeneous in biochemical and nutritional composition.…”