This work investigates a mechanism and degree for bubble interactions such as bubble clustering, coalescence and breakup to affect the liquid phase mass transfer coefficient k(L). Our previous k(L) data for a normal bubble column (NBC), internal loop airlift (ILBC) and external loop airlift (ELBC) are compared with k(LS) for single bubbles and k(L,BF) in the bubble flow (BF) at a fixed mean bubble diameter d(B). Our correlations of k(L)alpha epsilon(0.1)(G) (NBC and ILBC) and k(L)alpha epsilon(0.2)(G) (ELBC) have been found to arise from the relationship for gas holdup epsilon(G)=0.5(d(B)/l)(3), where l is the mean distance between the adjacent bubbles. The reported k(L),(BF) values were reproduced by the Higbie model with the average bubble slip velocity of (gd(B)/2)(0.5). A factor F=k(L,CTF)/k(L,BF) is defined to quantify an effect of the bubble interactions on k(L,CTF) in the churn-turbulent flow (CTF). The reported correlation gives F=0.5Eo(3/8), where Eo=gd(B)(2)rho(L)/sigma. Eo<6.4 and Eo>6.4 have been found to give the clustering regime and the coalescence and breakup regime, respectively. Our k(L),(CTF) data (NBC and ILBC) satisfied F=0.5Eo(3/8). F=(kL,ELBC)/k(L,BF) for the ELBC roughly correlates as F=1.3.