diff --git a/src/interpreter/env.rs b/src/interpreter/env.rs
index 9535445..2325da6 100644
--- a/src/interpreter/env.rs
+++ b/src/interpreter/env.rs
@@ -152,16 +152,15 @@ impl ModuleInstanceInterface for EnvModuleInstance {
 	}
 }
 
-pub fn env_module() -> Result<EnvModuleInstance, Error> {
-	let env_params = EnvParams::default();
-	debug_assert!(env_params.total_stack < env_params.total_memory);
-	debug_assert!((env_params.total_stack % LINEAR_MEMORY_PAGE_SIZE) == 0);
-	debug_assert!((env_params.total_memory % LINEAR_MEMORY_PAGE_SIZE) == 0);
+pub fn env_module(params: EnvParams) -> Result<EnvModuleInstance, Error> {
+	debug_assert!(params.total_stack < params.total_memory);
+	debug_assert!((params.total_stack % LINEAR_MEMORY_PAGE_SIZE) == 0);
+	debug_assert!((params.total_memory % LINEAR_MEMORY_PAGE_SIZE) == 0);
 	let builder = module()
 		// memory regions
 		.memory()
-			.with_min(env_params.total_memory / LINEAR_MEMORY_PAGE_SIZE)
-			.with_max(env_params.max_memory().map(|m| m / LINEAR_MEMORY_PAGE_SIZE))
+			.with_min(params.total_memory / LINEAR_MEMORY_PAGE_SIZE)
+			.with_max(params.max_memory().map(|m| m / LINEAR_MEMORY_PAGE_SIZE))
 			.build()
 			.with_export(ExportEntry::new("memory".into(), Internal::Memory(INDEX_MEMORY)))
 		// tables
@@ -174,13 +173,13 @@ pub fn env_module() -> Result<EnvModuleInstance, Error> {
 			.with_export(ExportEntry::new("STACK_BASE".into(), Internal::Global(INDEX_GLOBAL_STACK_BASE)))
 		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, true), InitExpr::new(vec![Opcode::I32Const(DEFAULT_STACK_BASE.transmute_into())])))
 			.with_export(ExportEntry::new("STACKTOP".into(), Internal::Global(INDEX_GLOBAL_STACK_TOP)))
-		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + env_params.total_stack).transmute_into())])))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + params.total_stack).transmute_into())])))
 			.with_export(ExportEntry::new("STACK_MAX".into(), Internal::Global(INDEX_GLOBAL_STACK_MAX)))
-		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + env_params.total_stack).transmute_into())])))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + params.total_stack).transmute_into())])))
 			.with_export(ExportEntry::new("DYNAMIC_BASE".into(), Internal::Global(INDEX_GLOBAL_DYNAMIC_BASE)))
-		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, true), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + env_params.total_stack).transmute_into())])))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, true), InitExpr::new(vec![Opcode::I32Const((DEFAULT_STACK_BASE + params.total_stack).transmute_into())])))
 			.with_export(ExportEntry::new("DYNAMICTOP_PTR".into(), Internal::Global(INDEX_GLOBAL_DYNAMICTOP_PTR)))
-			.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, env_params.allow_memory_growth), InitExpr::new(vec![Opcode::I32Const(env_params.total_memory.transmute_into())])))
+			.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, params.allow_memory_growth), InitExpr::new(vec![Opcode::I32Const(params.total_memory.transmute_into())])))
 			.with_export(ExportEntry::new("TOTAL_MEMORY".into(), Internal::Global(INDEX_GLOBAL_TOTAL_MEMORY)))
 		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, true), InitExpr::new(vec![Opcode::I32Const(0)])))
 			.with_export(ExportEntry::new("ABORT".into(), Internal::Global(INDEX_GLOBAL_ABORT)))
@@ -210,7 +209,7 @@ pub fn env_module() -> Result<EnvModuleInstance, Error> {
 			.build()
 			.with_export(ExportEntry::new("getTotalMemory".into(), Internal::Function(INDEX_FUNC_GET_TOTAL_MEMORY)));
 
-	EnvModuleInstance::new(env_params, builder.build())
+	EnvModuleInstance::new(params, builder.build())
 }
 
 impl Default for EnvParams {
diff --git a/src/interpreter/program.rs b/src/interpreter/program.rs
index 41141f8..33c179d 100644
--- a/src/interpreter/program.rs
+++ b/src/interpreter/program.rs
@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use parking_lot::RwLock;
 use elements::Module;
 use interpreter::Error;
-use interpreter::env::env_module;
+use interpreter::env::{self, env_module};
 use interpreter::module::{ModuleInstance, ModuleInstanceInterface};
 
 /// Program instance. Program is a set of instantiated modules.
@@ -21,8 +21,13 @@ pub struct ProgramInstanceEssence {
 impl ProgramInstance {
 	/// Create new program instance.
 	pub fn new() -> Result<Self, Error> {
+		ProgramInstance::with_env_params(env::EnvParams::default())
+	}
+
+	/// Create new program instance with custom env module params (mostly memory)
+	pub fn with_env_params(params: env::EnvParams) -> Result<Self, Error> {
 		Ok(ProgramInstance {
-			essence: Arc::new(ProgramInstanceEssence::new()?),
+			essence: Arc::new(ProgramInstanceEssence::with_env_params(params)?),
 		})
 	}
 
@@ -43,12 +48,16 @@ impl ProgramInstance {
 impl ProgramInstanceEssence {
 	/// Create new program essence.
 	pub fn new() -> Result<Self, Error> {
+		ProgramInstanceEssence::with_env_params(env::EnvParams::default())
+	}
+
+	pub fn with_env_params(env_params: env::EnvParams) -> Result<Self, Error> {
 		let mut modules = HashMap::new();
-		let env_module: Arc<ModuleInstanceInterface> = Arc::new(env_module()?);
+		let env_module: Arc<ModuleInstanceInterface> = Arc::new(env_module(env_params)?);
 		modules.insert("env".into(), env_module);
 		Ok(ProgramInstanceEssence {
 			modules: RwLock::new(modules),
-		})
+		})		
 	}
 
 	/// Get module reference.