How to get equations from zpk

Hey guys, I need some help. Please help me to separate zpk model to few parts

s = tf('s');

%Input density
Suu = -1.6/((s-4)*(s+4));

%Cospectral density
Sux = -0.8/((s+4)*(s-4)*(s^2 + 0.1*s + 1));

%Output density
Sxx = 0.3*(s - 4.163)*(s + 4.163)/((s+4)*(s-4)*(s^2 - 0.1*s + 1)*(s^2 + 0.1*s + 1));
Sxu = Sux';

SdxSxd = Sxx - (Sxu*Sux)/Suu; %Calculation of Sdx*Sxd
SdxSxd = zpk(SdxSxd);  

Zero/pole/gain:
               0.3
---------------------------------
(s^2 + 0.1s + 1) (s^2 - 0.1s + 1)

now I need to separate expressions of denominator and get smth like S1 = (s^2 + 0.1s + 1); S2 = (s^2 - 0.1s + 1); or S1 = [1 0.1 1]; S2 = [1 -0.1 1] how to extract zpk and do it right? thank you.