For the two-step processing procedure using lactic acid bacteria
and Bacillus sp. CS-1, the following experiment was conducted. To
obtain enough cell volume, pre-cultivation using lactic acid bacteria
was performed using each optimum medium as documented by
Chang et al. (2012b). Lignin and hemicellose degradation experiments
used 300 mL glass-stoppered Erlenmeyer flasks containing
100 mL of growth medium and 3 g of milled rice straw. Growth
medium had the following composition in 1000 mL of deionization
water: 3 g peptone; 15 g malt extracts; and 40 g glucose. Each precultivated
culture (0.25 mg protein mL1) of the two lactic acid
bacteria were inoculated in 100 mL of growth medium with milled
rice straw and incubated for 3 days at 120 rpm on a rotary shaker
at 30 C for the first processing procedure. Autoclaved growth
medium served as the control, with the pH of the growth medium
adjusted to 7 with NaOH (1.0 M) before autoclaving. Milled rice
straws were then separated by centrifugation (2180g for
15 min), rinsed with deionized water twice and reacted for a further
3 days in a BSGYP medium also containing Bacillus sp. CS-1
(the second processing procedure).