Problem with Arduino (hc-05) and App Inventor

Hello
We have a CO2 sensor to do in high school with an Arduino and an application for see the data with App Inventor. But, the data collected on the Arduino is not transmitted by the hc-05 sur l'application.
Attached the Arduino code and the App Inventor.

Thank you for your help.

bluetooth.println(ppm);

Desinger
ClientBluetooth.DelimiterByte 10

ReceiverText
numberofbytes -1

Here an example