The aim of this paper is to deal with BiHom-alternative algebras which are a generalization of alternative and
Hom-alternative algebras, their structure is defined with two
commuting multiplicative linear maps. We study cohomology and
one-parameter formal deformation theory of left BiHom-alternative
algebras. Moreover, we study central and $T_\theta$-extensions of
BiHom-alternative algebras and their relationship with
cohomology.
Finally, we investigate generalized derivations and give some relevant results.