ABSTRACTA preliminary investigation of the membrane lipid ofHalobacterium halobiumas a food additive. F. J. Post and N. F. Collins, Biology Department, Utah State University, Logan, Utah 84322.A study was made of the suitability of the diether phytanyl phosphatidyl glycerol phosphate lipid component of the cell membrane ofHalobacterium halobiumNRC 34003 as a potential food additive. The lipid was shown to be a possible emulsifier with a hydrophile‐lipophile balance (HLB) of7–8 producing a water in oil emulsion. Its use as a possible noncaloric fat substitute is also discussed. The lipid had a melting point at‐120to ‐150C and was nontoxic at an 0.8 g kg‐1, one‐dose exposure to mice either by feeding or by intraperitoneal injection. Some methods for increasing the yield of lipid a