Short commmunication The influence of tapioca on the growth, the activity of glucoamylase and pigment production of Monascus purpureus UKSW 40 in soybean-soaking wastewater Kris H. Timotius Satya Wacana Christian University, Salatiga, Indonesia, Tel.: 0062-298-321212, Fax: 0062-298-321433, E-mail: kh_timotius@uksw.edu Keywords: Food pigments, glucoamylase, Monascus purpureus, SSW, tapioca starch Summary The present study evaluates the usefulness of tapioca starch as additional carbon source for the growth of Monascus purpureus in soybean-soaking wastewater (SSW). The result revealed that M. purpureus grown on 2.0% (w/v) tapioca starch in SSW produced significantly (P < 0.05) higher amounts of biomass and production of the pigments (OD 400 and OD 500 ) when compared to those grown on glucose-or maltose-containing media. However, the glucoamylase activity of M. purpureus grown on the tapioca-SSW medium was not significantly increased when compared to those from the glucose-containing medium. Introduction Tapioca starch and soybean-soaking wastewater (SSW) are potentially cheap source of carbon and nitrogen for bioindustries in Java. These substrates are also available in large amounts throughout the year in Java (Handay- ani & Timotius 1998; Yongsmith 1998). Combinatory use of these substrates as growth medium for M. purpureus has never been reported. It is for these reasons that the present project was conducted to evaluate the effectiveness of this substrate on enzyme and pigment production by M. purpureus. SSW from tempe industries is not yet used as substrate for any kind of bio-based industry in Indonesia. At present SSW is only discarded into the rivers. Further- more, on preliminary investigation has revealed that soybean waste has a high nutrient content. It is estimated that over 3000 l of SSW is produced per day in Java. Thus, utilization of this substrate will reduced the level of pollution created by these discharges (Timotius & Utomo 1997; Timotius 1998). M. purpureus is a mould usually isolated from ‘‘Angkak’’ which is traditionally used as a food colorant in Asian Countries. A lot of work has been done on the chemistry and production aspects on solid and liquid culturing of ‘‘Angkak’’. This mould produces six pig- ments along with other secondary metabolites. Its pigments show considerable potential as food colorants (Lee et al. 1995; Sheu et al. 2000). The present study investigates the possible use of tapioca starch and SSW as substrates for the growth of M. purpureus and its production of glucoamylase and pigments. Materials and methods Source and growth of M. purpureus M. purpureus UKSW 40 was isolated from local ‘‘Angkak’’ and maintained on malt extract agar (MEA) slopes. Medium SSW was obtained from local tempe producers, and cooked for 10 min at 120 °C and then filtered to separate the insoluble materials before sterilization. The cooked and filtered SSW was diluted to 1.5% (v/v) Brix using a viscometer and adjusted to pH 6. The media was then sterilized by heating to 121 °C for 15 min. Test substrate Tapioca starch was obtained from the local manufac- turer (Salatiga). Glucose and maltose were obtained from Merck Chemical Company. Cultivation method Inoculum was prepared by culturing the mould in MEA. The spores were then harvested in physiological saline World Journal of Microbiology & Biotechnology (2005) 21:615–617 Ó Springer 2005 DOI 10.1007/s11274-004-1892-2