Looking for a substituent of spinach (Spinacia oleracea) chloroplasts

Spinach’s chloroplasts electron transport features are often adapted to build biofuel cells or biosensors for environment conservation. This approach may raise food security issues. The present study aimed to test on in vitro functional activity of chloroplasts from selected underutilized leaves of: Pandan (Pandanus amaryllifolius), oil palm (Elaeis guineensis) and water lettuce (Pistia stratiotes) in comparison with spinach (Spinacia oleracea). The leaves’ electrical conductivity was measured to evaluate the initial cell permeability. We applied Hill’s reaction to determine the photoreduction capacity of the chloroplasts. Initial electrical conductivity of leaves ranged from 11.5 to 18.5 µs/cm/g followed the order of water lettuce<oil palm frond=pandan<spinach which can be used as a simple quality marker for the leaves’ chloroplasts. Chloroplasts of oil palm frond and water lettuce showed low photoreduction rate of 14 to 22%. On the other hand, the chloroplasts of both spinach and pandan leaves exerted an initial photoreduction rate which was above 90%. The photoreduction rate of these chloroplasts remained to above 60% even after 30 day-storage at −20°C. In comparison with spinach, pandan leaves’ chloroplasts possessed similar in vitro functional activity and storage stability at 4°C and −20°C. This warrants further investigation on chloroplasts of pandan leaves for higher-value applications.