Ó Springer 2005
acid production using Lactobacillus casei in solid-state
Pappy JohnRojan, Kesavan Madhavan Nampoothiri*, Athira Syamaprasad Nair & Ashok Pandey
Biotechnology Division, Regional Research Laboratory (CSIR), 695 019, Trivandrum, Kerala, India *Author for correspondence(Fax: +91-471-2491712; E-mail: firstname.lastname@example.org)
Received 27 May 2005; Revisions requested 15 June 2005 and 19 July 2005; Revisions received 14 July 2005 and 15 August 2005; Accepted 22 August2005
Key words: cassava bagasse starch hydrolysate, Lactobacillus casei, L-lactic acid, solid-state fermentation, sugarcane bagasse
Abstract Lactobacillus casei was grown at 37 °C on sugarcanebagasse (5 g) soaked with cassava starch hydrolysate (ﬁnal moistening volume 34 ml) containing 3 g reducing sugar in a solid-state condition. The maximum yield of L-lactic acid after various processoptimisations was 2.9 g/5 g initial substrate corresponding to 97% conversion of sugar to lactic acid with initial substrate moisture of 72%. Introduction Lactic acid and its derivatives have gainedprominence because of its many applications in food, pharmaceutical, cosmetic, textile and chemical industries (Vickroy 1985, Dimerci et al. 1993, Senthuran et al. 1997). Its use as a precursor for thebiodegradable plastic, polylactic acid (PLA), has received much consideration (Senthuran et al. 1997). Since only L(+)-lactic acid can be catabolised in humans, this isomer is preferred for foodapplications. By fermentation we can produce L(+)-, D())- or DL-lactic acid depending upon which organism is used. Solid state fermentation (SSF) has various advantages over submerged fermentations, such aslow capital investment, better product recovery, less water output etc. (Pandey et al. 2001). SSF carried out on inert solid material can provide good fermentation conditions and with a high purity...