There isn't a built-in function to import biadjacency matrices. You can create an adjacency matrix A from the biadjacency matrix B as
0 B
BT 0
where BT is the transpose of B.
Then you can load it directly,
In [1]: import numpy as np
In [2]: import networkx as nx
In [3]: b = np.matrix([[1,0,1],[0,1,1]])
In [4]: r,s = b.shape
In [5]: a = np.vstack( (np.hstack((np.zeros((r,r)),b)), np.hstack((b.T,np.zeros((s,s)) ))) )
In [6]: G = nx.Graph(a)
In [7]: G.edges()
Out[7]: [(0, 2), (0, 4), (1, 3), (1, 4)]
The nodes are labeled 0,1 (part 1) and 2,3,4 (part 2).