Correction to: Polymer Journal (2011) 43, 414–420; published online 19 January 2011; doi:10.1038/pj.2010.142

In the above article, unit given for x axis variables for Figure 8 line graph was wrong. It should have been cultivation time in number of days, as shown below.

Figure 8
figure 1

Biochemical oxygen demand-biodegradation test of the poly(γ-glutamic acid) (PGA) gel (solid line) and aniline (dashed line) using activated sludge at 25 °C. The PGA gel was prepared with 50 mg of PGA dissolved in 0.35 ml of 1.0-M NaOH, 17.7 mg of L-lysine·HCl dissolved in 0.08 ml of water and 1.0-M NaOH to adjust the pH to 8.9, and 54 mg of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride dissolved in 0.20 ml of water at 25 °C for 24 h.