Abstract: The present disclosure provides a composition comprising: an extracellular polymeric substance produced by microalgae; plant growth promoting Gram-negative bacteria; and an agriculturally acceptable carrier. Also provided are an isolated biologically pure culture of Parachlorella kessleri Accession No. NCMA 202103001, a mutant thereof having all the identifying characteristics thereof, or a cell-free preparation or extracellular polymeric substance thereof, which may be used for plant enhancement and improving health of soil.

Abstract: The present disclosure relates to an agricultural composition comprising: a) plant growth promoting Gram-negative bacteria; b) a desiccation protectant selected from the group consisting of: a carboxyalkylcellulose or derivative or salt thereof, a hydroxyalkylcellulose or derivative or salt thereof, an alginate or derivative or salt thereof, trehalose or a derivative or salt thereof; tamarind seed gum, locust bean gum, xanthan gum, tara gum, guar gum, pectin, pullulan, psyllium seed gum, and carrageenan; and combinations thereof; and c) an agriculturally acceptable carrier. The disclosure also provides a method of increasing resistance to desiccation in plant growth promoting Gram-negative bacteria, the method comprising adding a desiccation protectant to the plant growth promoting Gram-negative bacteria.